%0 journal article %@ 0934-0866 %A Störmann, F., Roch, T., Lendlein, A., Wischke, C. %D 2024 %J Particle & Particle Systems Characterization %R doi:10.1002/ppsc.202300099 %T Microfluidic templating and initiator-free photocrosslinking of protein-loaded PCL microcapsules %U https://doi.org/10.1002/ppsc.202300099 %X Polymer network materials are interesting alternatives to thermoplastic polymers. Here, the preparation of polymer capsules is investigated, which are made from poly(ε-caprolactone) (PCL) networks and are compartmentalized in a crosslinked PCL shell and a core that is suitable to enclose payloads of interest. Aided by microfluidic templating, PCL network capsules with a narrow size distribution (176 ± 5 µm) and thin shells (≈7.5 µm) are formed from 4-arm star-shaped 12 kDa PCL precursors by photoinitiator-free UV light-induced radical polymerization of methacrylate end-groups. FITC-BSA is encapsulated as a model protein. The physicochemical characterization of the capsules indicated a partial crosslinking of methacrylate endgroups into netpoints. Microscopy revealed a fraction of collapsed capsules that are discussed in the context of network stability and mechanical stress created at the capsule interfaces during solvent removal. The incubation of particles with human embryonic kidney (HEK) cells showed good cell compatibility, suggesting their potential use in biosciences and beyond. %0 journal article %@ 1438-7492 %A Folikumah, M.Y., Behl, M., Lendlein, A., Neffe, A.T. %D 2023 %J Macromolecular Materials and Engineering %N 11 %P 2300146 %R doi:10.1002/mame.202300146 %T A 4-Arm PEG-Thiodepsipeptide Precursor Enables Gelatinase-promoted Hydrogel Formation %U https://doi.org/10.1002/mame.202300146 11 %X In situ hydrogelation of injectable precursors upon biological stimulus is relevant to generate hydrogels under mild conditions and, potentially, at a biological side of interest. Here, it is shown that hydrolytic enzymes can be used to initiate the formation of covalent hydrogel networks, realizing a cleavage-leading-to-gelation strategy. For this purpose, a two-component system is used, consisting of a 4-arm polyethylene glycol-thiodepsipeptide conjugate, PEG4TDPo containing the matrix metalloproteinases MMP-2- and MMP-9-cleavable Ac-Pro-Leu-Gly#SLeu-Leu-Gly- thiodepsipeptide sequence releasing a thiol upon hydrolysis, and a maleimide functionalized 4-armed PEG (PEG4MAL). PEG4TDPo is synthesized in a PEG-functionalization protocol involving convergent and divergent synthetic steps without the need for rigorous purification procedures. In a fluorometric assay, it is shown that the construct is in fact cleaved by both investigated MMPs. PEG4TDPo in the presence of 10 wt.% PEG4MAL formed hydrogels upon addition of MMP-2 or -9 with average gelation times of 28 and 40 min, respectively, as is investigated by rheology. The much faster gelation times compared to the enzyme-free system showed the specific input of the enzymatic reactions. The MMP-assisted activation and crosslinking strategy can potentially become useful by targeting tissues showing an increased expression of MMPs, such as cancers, or to detect MMPs. %0 journal article %@ 1944-8244 %A Xu, X., Wang, W., Zou, J., Kratz, K., Deng, Z., Lendlein, A., Ma, N. %D 2023 %J ACS Applied Materials and Interfaces %N 25 %P 29752–29766 %R doi:10.1021/acsami.3c01481 %T Histone modification of osteogenesis related genes triggered by substrate topography promotes human mesenchymal stem cell differentiation %U https://doi.org/10.1021/acsami.3c01481 25 %X The clinical success of orthopedic implants is closely related to their integration in the bone tissue promoted by rough device surfaces. The biological response of precursor cells to their artificial microenvironments plays a critical role in this process. In this study, we elucidated the relation between cell instructivity and surface microstructure of polycarbonate (PC)-based model substrates. The rough surface structure (hPC) with an average peak spacing (Sm) similar to the trabecular spacing of trabecular bone improved osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs), as compared to the smooth surface (sPC) and the surface with a moderate Sm value (mPC). The hPC substrate promoted the cell adhesion and assembling of F-actin and enhanced cell contractile force by upregulating phosphorylated myosin light chain (pMLC) expression. The increased cell contractile force led to YAP nuclear translocation and the elongation of cell nuclei, presenting higher levels of active form of Lamin A/C. The nuclear deformation alternated the histone modification profile, particularly the decrease of H3K27me3 and increase of H3K9ac on the promoter region of osteogenesis related genes (ALPL, RUNX2, and OCN). Mechanism study using inhibitors and siRNAs elucidated the role of YAP, integrin, F-actin, myosin, and nuclear membrane proteins in such a regulatory process of surface topography on stem cell fate. These mechanistical insights on the epigenetic level give a new perspective in understanding of the interaction of substrate and stem cells as well as provide valuable criteria for designing bioinstructive orthopedic implants. %0 journal article %@ 2196-7350 %A Nie, Y., Liu, Y., Xu, X., Wang, W., Scharnagl, N., Heuchel, M., Lendlein, A., Ma, N. %D 2023 %J Advanced Materials Interfaces %N 18 %P 2202509 %R doi:10.1002/admi.202202509 %T A model of using the asymmetric polydopamine thin film for mimicking epithelial folding in vitro %U https://doi.org/10.1002/admi.202202509 18 %X The basement membrane (BM) is a biointeractive ultrathin network with distinct composition and organization of its epithelial and stromal sides, which render BMs with asymmetric biofunctions and mechanical properties. There are difficulties in the recapitulation of the highly hierarchical structure and function of BM. Here, the interfacial assembly method for the generation of BM mimics is applied. Dopamine is the starting material for the polymerization and assembly of polydopamine (PDA) into asymmetric materials. Compared to the PDA coating formed at the solid/liquid interface (≈20 nm), the PDA film formed at the air/liquid interface displays a thickness of ≈100 nm. Moreover, it possesses an asymmetric surface topography and an apparent Young's modulus of ≈1.0 MPa, which is structurally and mechanically similar to natural BMs. Of interest, the airside and the waterside of the PDA film exhibit differences in their adhesion affinity to the human skin keratinocytes. With stronger active mechanical processes between living cells and the waterside of PDA film, epithelial folding could be mimicked. Together, the PDA film is able to recapitulate the structural and mechanical complexity of natural BMs, indicating the prospective future of using PDA films for in vitro modeling cell-BM interaction and tissue formation. %0 journal article %@ 2073-4360 %A Farhan, M., Hartstein, D.S., Pieper, Y., Behl, M., Lendlein, A., Neffe, A.T. %D 2023 %J Polymers %N 9 %P 2233 %R doi:10.3390/polym15092233 %T Bio-inspired magnetically controlled reversibly actuating multimaterial fibers %U https://doi.org/10.3390/polym15092233 9 %X Movements in plants, such as the coiling of tendrils in climbing plants, have been studied as inspiration for coiling actuators in robotics. A promising approach to mimic this behavior is the use of multimaterial systems that show different elastic moduli. Here, we report on the development of magnetically controllable/triggerable multimaterial fibers (MMFs) as artificial tendrils, which can reversibly coil and uncoil on stimulation from an alternating magnetic field. These MMFs are based on deformed shape-memory fibers with poly[ethylene-co-(vinyl acetate)] (PEVA) as their core and a silicone-based soft elastomeric magnetic nanocomposite shell. The core fiber provides a temperature-dependent expansion/contraction that propagates the coiling of the MMF, while the shell enables inductive heating to actuate the movements in these MMFs. Composites with mNP weight content ≥ 15 wt% were required to achieve heating suitable to initiate movement. The MMFs coil upon application of the magnetic field, in which a degree of coiling N = 0.8 ± 0.2 was achieved. Cooling upon switching OFF the magnetic field reversed some of the coiling, giving a reversible change in coiling ∆n = 2 ± 0.5. These MMFs allow magnetically controlled remote and reversible actuation in artificial (soft) plant-like tendrils, and are envisioned as fiber actuators in future robotics applications. %0 journal article %@ 0935-9648 %A Farhan, M., Klimm, F., Thielen, M., Rešetič, A., Bastola, A., Behl, M., Speck, T., Lendlein, A. %D 2023 %J Advanced Materials %N 2 %P 2211902 %R doi:10.1002/adma.202211902 %T Artificial tendrils mimicking plant movements by mismatching modulus and strain in core and shell %U https://doi.org/10.1002/adma.202211902 2 %X Motile organs have evolved in climbing plants enabling them to find a support and, after secure attachment, to reach for sunlight without investing in a self-supporting stem. Searching movements, the twining of stems, and the coiling of tendrils are involved in successful plant attachment. Such coiling movements have great potential in robotic applications, especially if they are reversible. Here, the underlying mechanism of tendril movement based on contractile fibers is reported, as illustrated by a function–morphological analysis of tendrils in several liana species and the encoding of such a principle in a core–shell multimaterial fiber (MMF) system. MMFs are composed of a shape-memory core fiber (SMCF) and an elastic shell. The shape-memory effect of the core fibers enables the implementation of strain mismatch in the MMF by physical means and provides thermally controlled reversible motion. The produced MMFs show coiling and/or uncoiling behavior, with a high reversible actuation magnitude of ≈400%, which is almost 20 times higher compared with similar stimuli for sensitive soft actuators. The movements in these MMFs rely on the crystallization/melting behavior of oriented macromolecules of SMCF. %0 journal article %@ 0264-1275 %A Wang, X., Behl, M., Lendlein, A., Balk, M. %D 2023 %J Materials & Design %P 111511 %R doi:10.1016/j.matdes.2022.111511 %T Responses to single and multiple temperature-, medium-, and pH-stimuli triggering reversible shape shifts in hydrogel actuators %U https://doi.org/10.1016/j.matdes.2022.111511 %X Adaptivity is an essential capability of creatures to develop skills for surviving and reproducing. Mimicking such behavior would enable the design of biologically inspired functions. Hydrogel actuators are promising candidate materials capable of stimuli-responsive movements via water uptake and release. Here, for the first time, the adaptive-like movement of reprogrammable hydrogel actuators is demonstrated by integrating two independent functions: a temperature-triggered actuation and a medium- and pH-based modulated swelling, into one multiphase network. Reversible crystallization of poly(ε-caprolactone) (PCL) provided bending movements up to 71° (realized by temperature changes between 5 °C and 40 °C). Changing solvent from water to ethanol increased swellability up to 240 vol%. Bending angles decreased by 32° as some PCL fractions are dissolved in ethanol and cannot participate in the crystallization-induced elongation guiding the movement. When the actuators were modified with acrylic acid moieties, a modulated swelling between 270 vol% at pH = 13 and 130 vol% at pH = 1 was achieved. The resulting swelling/deswelling response induced reversible bending movements up to 54°. In consequence, the coupled functionalities (actuation and modulated swelling) resulted in conditioned actuation behavior as an intermediate feature between stimuli-sensitivity and adaptivity. %0 journal article %@ 1616-301X %A Bhuvanesh, T., Nie, Y., Machatschek, R., Ma, N., Lendlein, A. %D 2023 %J Advanced Functional Materials %N 46 %P 2304268 %R doi:10.1002/adfm.202304268 %T Laminin - dynamic bonds enable multifunctionality in a biological 2D network %U https://doi.org/10.1002/adfm.202304268 46 %X A layer of laminins, assembled on a thin sheet of collagen type IV (Col-IV) forms the backbone of the basal lamina, which controls biological processes such as embryogenesis, tissue homeostasis, and development. Here, the dynamic functions of laminin-111 (Lam-111) in ultrathin films at the air–water interface are investigated. It is shown that the 2D confinement induces polymerization and that expansion via adlayer formation occurs only with extended growth time. The highly robust self-assembly enables the functionalization of surfaces with cross-linked 2D Lam-111 networks of defined thickness using little more than a beaker. The 2D laminin material also displays two dynamic functions required for the maintenance of tissues – the capability for self-renewal and self-healing. By assembling Lam-111 2D networks at the surface of Col-IV sheets, freestanding bilayers closely mimicking the basal lamina can be produced in vitro. There is a marked difference in miPSC spreading and adhesion force between Lam-111 sheets assembled in the presence or absence of Col-IV. These fundamental studies highlight the importance of dynamic functions, encoded into the molecular structure of the building blocks, for the assembly, maintenance, and functioning of the complex material systems found in natural tissues and can provide cues for the molecular design of resilient technical systems. %0 journal article %@ 2162-2531 %A Moradian, H., Roch, T., Anthofer, L., Lendlein, A., Gossen, M. %D 2022 %J Molecular Therapy Nucleic Acids %P 854-869 %R doi:10.1016/j.omtn.2022.01.004 %T Chemical modification of uridine modulates mRNA-mediated proinflammatory and antiviral response in primary human macrophages %U https://doi.org/10.1016/j.omtn.2022.01.004 %X In vitro transcribed (IVT)-mRNA has been accepted as a promising therapeutic modality. Advances in facile and rapid production technologies make IVT-mRNA an appealing alternative to protein- or virus-based medicines. Robust expression levels, lack of genotoxicity and their manageable immunogenicity benefit its clinical applicability. We postulated that innate immune responses of therapeutically relevant human cells can be tailored or abrogated by combinations of 5’-end and internal IVT-mRNA modifications. Using primary human macrophages as targets, our data show the particular importance of uridine modifications for IVT-mRNA performance. Among five nucleotide modification schemes tested, 5-methoxy-uridine outperformed other modifications up to 4-fold increased transgene expression, triggering moderate proinflammatory and non-detectable antiviral responses. Macrophage responses against IVT-mRNAs exhibiting high immunogenicity (e.g., pseudouridine) could be minimized upon HPLC purification. Conversely, 5’-end modifications, had only modest effects on mRNA expression and immune responses. Our results revealed how the uptake of chemically modified IVT-mRNA impacts human macrophages, responding with distinct patterns of innate immune responses concomitant with increased transient transgene expression. We anticipate our findings are instrumental to predictively address specific cell responses required for wide range of therapeutic applications from eliciting controlled immunogenicity in mRNA vaccines to, e.g., completely abrogating cell activation in protein replacement therapies. %0 journal article %@ 1386-0291 %A Lau, S., Gossen, M., Lendlein, A., Jung, F. %D 2022 %J Clinical Hemorheology and Microcirculation %N 3 %P 191-203 %R doi:10.3233/CH-211294 %T Differential sensitivity of assays for determining vein endothelial cell senescence %U https://doi.org/10.3233/CH-211294 3 %X In vivo endothelialization of polymer-based cardiovascular implant materials is a promising strategy to reduce the risk of platelet adherence and the subsequent thrombus formation and implant failure. However, endothelial cells from elderly patients are likely to exhibit a senescent phenotype that may counteract endothelialization. The senescence status of cells should therefore be investigated prior to implantation of devices designed to be integrated in the blood vessel wall. Here, human umbilical vein endothelial cells (HUVEC) were cultivated up to passage (P) 4, 10 and 26/27 to determine the population doubling time and the senescence status by four different methods. Determination of the senescence-associated β-galactosidase activity (SA-β-Gal) was carried out by colorimetric staining and microscopy (i), as well as by photometric quantification (ii), and the expression of senescence-associated nuclear proteins p16 and p21 as well as the proliferation marker Ki67 was assessed by immunostaining (iii), and by flow cytometry (iv). The population doubling time of P27-cells was remarkably greater (103±65 h) compared to P4-cells (24±3 h) and P10-cell (37±15 h). Among the four different methods tested, the photometric SA-β-Gal activity assay and the flow cytometric determination of p16 and Ki67 were most effective in discriminating P27-cells from P4- and P10-cells. These methods combined with functional endothelial cell analyses might aid predictions on the performance of implant endothelialization in vivo. %0 journal article %@ 1613-6810 %A Liu, Y., Gould, O., Kratz, K., Lendlein, A. %D 2022 %J Small %N 5 %P 2104621 %R doi:10.1002/smll.202104621 %T On Demand Sequential Release of (Sub)Micron Particles Controlled by Size and Temperature %U https://doi.org/10.1002/smll.202104621 5 %X Polymeric devices capable of releasing submicron particles (subMP) on demand are highly desirable for controlled release systems, sensors, and smart surfaces. Here, a temperature-memory polymer sheet with a programmable smooth surface served as matrix to embed and release polystyrene subMP controlled by particle size and temperature. subMPs embedding at 80 °C can be released sequentially according to their size (diameter D of 200 nm, 500 nm, 1 µm) when heated. The differences in their embedding extent are determined by the various subMPs sizes and result in their distinct release temperatures. Microparticles of the same size (D ≈ 1 µm) incorporated in films at different programming temperatures Tp (50, 65, and 80 °C) lead to a sequential release based on the temperature-memory effect. The change of apparent height over the film surface is quantified using atomic force microscopy and the realization of sequential release is proven by confocal laser scanning microscopy. The demonstration and quantification of on demand subMP release are of technological impact for assembly, particle sorting, and release technologies in microtechnology, catalysis, and controlled release. %0 journal article %@ 0884-2914 %A Machatschek, R., Heuchel, M., Lendlein, A. %D 2022 %J Journal of Materials Research %N 1 %P 67-76 %R doi:10.1557/s43578-021-00339-7 %T Thin-layer studies on surface functionalization of polyetherimide: Hydrolysis versus amidation %U https://doi.org/10.1557/s43578-021-00339-7 1 %X Among the high-performance and engineering polymers, polyimides and the closely related polyetherimide (PEI) stand out by their capability to react with nucleophiles under relatively mild conditions. By targeting the phthalimide groups in the chain backbone, post-functionalization offers a pathway to adjust surface properties such as hydrophilicity, solvent resistance, and porosity. Here, we use ultrathin PEI films on a Langmuir trough as a model system to investigate the surface functionalization with ethylene diamine and tetrakis(4-aminophenyl)porphyrin as multivalent nucleophiles. By means of AFM, Raman spectroscopy, and interfacial rheology, we show that hydrolysis enhances the chemical and mechanical stability of ultrathin films and allows for the formation of EDC/NHS-activated esters. Direct amidation of PEI was achieved in the presence of a Lewis acid catalyst, resulting in free amine groups rather than cross-linking. When comparing amidation with hydrolysis, we find a greater influence of the latter on material properties. %0 journal article %@ 2329-2237 %A Tarazona, N., Machatschek, R., Balcucho, J., Castro-Mayorga, J., Saldarriaga, J., Lendlein, A. %D 2022 %J MRS Energy & Sustainability %P 28-34 %R doi:10.1557/s43581-021-00015-7 %T Opportunities and challenges for integrating the development of sustainable polymer materials within an international circular (bio)economy concept %U https://doi.org/10.1557/s43581-021-00015-7 %X Leading-edge polymer-based materials for consumer and advanced applications are necessary to achieve sustainable development at a global scale. It is essential to understand how sustainability can be incorporated in these materials via green chemistry, the integration of bio-based building blocks from biorefineries, circular bioeconomy strategies, and combined smart and functional capabilities. %0 journal article %@ 2059-8521 %A Zhou, S., Xu, X., Ma, N., Jung, F., Lendlein, A. %D 2022 %J MRS Advances %P 354-359 %R doi:10.1557/s43580-021-00132-y %T Prediction of the epichlorohydrin derived cytotoxic substances from the eluent of poly(glycerol glycidyl ether) films %U https://doi.org/10.1557/s43580-021-00132-y %X Glycerol-based epoxy networks have great potential for surface functionalization, providing anti-microbial and protein repellant function. However, the synthesis of glycerol glycidyl ether (GGE) monomer often requires excessive epichlorohydrin (ECH). ECH derived organochloride containing byproducts from monomer production maybe present in the eluent of the polymer networks prepared by cationic ring-opening polymerization. Here, the cytotoxicity analysis revealed cell damages in contact with the polyGGE eluent. The occurrence of organochlorides, which was predicted based on the data from high-performance liquid chromatography/electrospray ionization mass spectrometry, as confirmed by a constant chloride level in GGE and polyGGE, and by a specific peak of C–Cl in infrared spectra of GGE. The resulting polyGGE was densely crosslinked, which possibly contribute to the trapping of organochlorides. These results provide a valuable information for exploring the toxins leaching from polyGGE and propose a feasible strategy for minimizing the cytotoxicity via reducing their crosslink density. %0 journal article %@ 2196-7350 %A Tartivel, L., Blocki, A., Braune, S., Jung, F., Behl, M., Lendlein, A. %D 2022 %J Advanced Materials Interfaces %N 6 %P 2101588 %R doi:10.1002/admi.202101588 %T An Inverse Shape-Memory Hydrogel Scaffold Switching Upon Cooling in a Tissue-Tolerated Temperature Range %U https://doi.org/10.1002/admi.202101588 6 %X Tissue reconstruction has an unmet need for soft active scaffolds that enable gentle loading with regeneration-directing bioactive components by soaking up but also provide macroscopic dimensional stability. Here microporous hydrogels capable of an inverse shape-memory effect (iSME) are described, which in contrast to classical shape-memory polymers (SMPs) recover their permanent shape upon cooling. These hydrogels are designed as covalently photo cross-linked polymer networks with oligo(ethylene glycol)-oligo(propylene glycol)-oligo(ethylene glycol) (OEG-OPG-OEG) segments. When heated after deformation, the OEG-OPG-OEG segments form micelles fixing the temporary shape. Upon cooling, the micelles dissociate again, the deformation is reversed and the permanent shape is obtained. Applicability of this iSME is demonstrated by the gentle loading of platelet-rich plasma (PRP) without causing any platelet activation during this process. PRP is highly bioactive and is widely acknowledged for its regenerative effects. Hence, the microporous inverse shape-memory hydrogel (iSMH) with a cooling induced pore-size effect represents a promising candidate scaffold for tissue regeneration for potential usage in minimally invasive surgery applications. %0 journal article %@ 2352-4928 %A Mazurek-Budzyńska, M., Behl, M., Neumann, R., Lendlein, A. %D 2022 %J Materials Today Communications %P 102966 %R doi:10.1016/j.mtcomm.2021.102966 %T 4D-actuators by 3D-printing combined with water-based curing %U https://doi.org/10.1016/j.mtcomm.2021.102966 %X The shape and the actuation capability of state of the art robotic devices typically relies on multimaterial systems from a combination of geometry determining materials and actuation components. Here, we present multifunctional 4D-actuators processable by 3D-printing, in which the actuator functionality is integrated into the shaped body. The materials are based on crosslinked poly(carbonate-urea-urethane) networks (PCUU), synthesized in an integrated process, applying reactive extrusion and subsequent water-based curing. Actuation capability could be added to the PCUU, prepared from aliphatic oligocarbonate diol, isophorone diisocyanate (IPDI) and water, in a thermomechanical programming process. When programmed with a strain of εprog = 1400% the PCUU networks exhibited actuation apparent by reversible elongation ε'rev of up to 22%. In a gripper a reversible bending ε'rev(bend) in the range of 37–60% was achieved when the actuation temperature (Thigh) was varied between 45 °C and 49 °C. The integration of actuation and shape formation could be impressively demonstrated in two PCUU-based reversible fastening systems, which were able to hold weights of up to 1.1 kg. In this way, the multifunctional materials are interesting candidate materials for robotic applications where a freedom in shape design and actuation is required as well as for sustainable fastening systems. %0 journal article %@ 1616-301X %A Tung, W.T., Maring, J.A., Xu, X., Liu, Y., Becker, M., Somesh, D.B., Klose, K., Wang, W., Sun, X., Ullah, I., Kratz, K., Neffe, A.T., Stamm, C., Ma, N., Lendlein, A. %D 2022 %J Advanced Functional Materials %N 31 %P 2110179 %R doi:10.1002/adfm.202110179 %T In Vivo Performance of a Cell and Factor Free Multifunctional Fiber Mesh Modulating Postinfarct Myocardial Remodeling %U https://doi.org/10.1002/adfm.202110179 31 %X Guidance of postinfarct myocardial remodeling processes by an epicardial patch system may alleviate the consequences of ischemic heart disease. As macrophages are highly relevant in balancing immune response and regenerative processes their suitable instruction would ensure therapeutic success. A polymeric mesh capable of attracting and instructing monocytes by purely physical cues and accelerating implant degradation at the cell/implant interface is designed. In a murine model for myocardial infarction the meshes are compared to those either coated with extracellular matrix or loaded with induced cardiomyocyte progenitor cells. All implants promote macrophage infiltration and polarization in the epicardium, which is verified by in vitro experiments. 6 weeks post-MI, especially the implantation of the mesh attenuates left ventricular adverse remodeling processes as shown by reduced infarct size (14.7% vs 28–32%) and increased wall thickness (854 µm vs 400–600 µm), enhanced angiogenesis/arteriogenesis (more than 50% increase compared to controls and other groups), and improved heart function (ejection fraction = 36.8% compared to 12.7–31.3%). Upscaling as well as process controls is comprehensively considered in the presented mesh fabrication scheme to warrant further progression from bench to bedside. %0 journal article %@ 2059-8521 %A Zhang, S., Liu, Y., Machatschek, R., Lendlein, A. %D 2022 %J MRS Advances %N 4 %P 56-62 %R doi:10.1557/s43580-021-00160-8 %T Ultrathin collagen type I films formed at the air-water interface %U https://doi.org/10.1557/s43580-021-00160-8 4 %X Collagen-based biomaterials with oriented fibrils have shown great application potential in medicine. However, it is still challenging to control the type I collagen fibrillogenesis in ultrathin films. Here, we report an approach to produce cohesive and well-organized type I collagen ultrathin films of about 10 nm thickness using the Langmuir-Blodgett technique. Ellipsometry, rheology, and Brewster angle microscopy are applied to investigate in situ how the molecules behave at the air-water interface, both at room temperature and 37 °C. The interfacial storage modulus observed at room temperature vanishes upon heating, indicating the existence and disappearance of the network structure in the protein nanosheet. The films were spanning over holes as large as 1 mm diameter when transferred at room temperature, proving the strong cohesive interactions. A highly aligned and fibrillar structure was observed by atomic force microscopy (AFM) and optical microscopy. %0 journal article %@ 2159-6859 %A Moradian, H., Gossen, M., Lendlein, A. %D 2022 %J MRS Communications %P 145-153 %R doi:10.1557/s43579-021-00128-7 %T Co-delivery of genes can be confounded by bicistronic vector design %U https://doi.org/10.1557/s43579-021-00128-7 %X Maximizing the efficiency of nanocarrier-mediated co-delivery of genes for co-expression in the same cell is critical for many applications. Strategies to maximize co-delivery of nucleic acids (NA) focused largely on carrier systems, with little attention towards payload composition itself. Here, we investigated the effects of different payload designs: co-delivery of two individual “monocistronic” NAs versus a single bicistronic NA comprising two genes separated by a 2A self-cleavage site. Unexpectedly, co-delivery via the monocistronic design resulted in a higher percentage of co-expressing cells, while predictive co-expression via the bicistronic design remained elusive. Our results will aid the application-dependent selection of the optimal methodology for co-delivery of genes. %0 journal article %@ 2399-7532 %A Mazzolai, B., Mondini, A., Del Dottore, E., Margheri, L., Carpi, F., Suzumori, K., Cianchetti, M., Speck, T., Smoukov, S.K., Burgert, I., Keplinger, T., Siqueira, G.D.F., Vanneste, F., Goury, O., Duriez, C., Nanayakkara, T., Vanderborght, B., Brancart, J., Terryn, S., Rich, S.I., Liu, R., Fukuda, K., Someya, T., Calisti, M., Laschi, C., Sun, W., Wang, G., Wen, L., Baines, R., Patiballa, S.K., Kramer-Bottiglio, R., Rus, D., Fischer, P., Simmel, F.C., Lendlein, A. %D 2022 %J Multifunctional Materials %N 3 %P 032001 %R doi:10.1088/2399-7532/ac4c95 %T Roadmap on soft robotics: multifunctionality, adaptability and growth without borders %U https://doi.org/10.1088/2399-7532/ac4c95 3 %X Soft robotics aims at creating systems with improved performance of movement and adaptability in unknown, challenging, environments and with higher level of safety during interactions with humans. This Roadmap on Soft Robotics covers selected aspects for the design of soft robots significantly linked to the area of multifunctional materials, as these are considered a fundamental component in the design of soft robots for an improvement of their peculiar abilities, such as morphing, adaptivity and growth. The roadmap includes different approaches for components and systems design, bioinspired materials, methodologies for building soft robots, strategies for the implementation and control of their functionalities and behaviour, and examples of soft-bodied systems showing abilities across different environments. For each covered topic, the author(s) describe the current status and research directions, current and future challenges, and perspective advances in science and technology to meet the challenges. %0 journal article %@ 0884-2914 %A Hoffmann, F., Machatschek, R., Lendlein, A. %D 2022 %J Journal of Materials Research %P 1093-1101 %R doi:10.1557/s43578-022-00495-4 %T Analytical model and Monte Carlo simulations of polymer degradation with improved chain cut statistics %U https://doi.org/10.1557/s43578-022-00495-4 %X The degradation of polymers is described by mathematical models based on bond cleavage statistics including the decreasing probability of chain cuts with decreasing average chain length. We derive equations for the degradation of chains under a random chain cut and a chain end cut mechanism, which are compared to existing models. The results are used to predict the influence of internal molecular parameters. It is shown that both chain cut mechanisms lead to a similar shape of the mass or molecular mass loss curve. A characteristic time is derived, which can be used to extract the maximum length of soluble fragments l of the polymer. We show that the complete description is needed to extract the degradation rate constant k from the molecular mass loss curve and that l can be used to design polymers that lose less mechanical stability before entering the mass loss phase. %0 conference lecture %@ %A Maring, J., Becker, M., Tung, W., Gossen, M., Stamm, C., Ma, N., Lendlein, A. %D 2022 %J 40. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheologie e.V. %T Immune response to electrospun PEEU fiber meshes %U %X %0 conference lecture %@ %A Behl, M., Tartivel, L., You, Z., Balk, M., Blocki, A., Lendlein, A. %D 2022 %J MRS Spring Meeting 2022 %T Sequential coupling of functions in hydrogels enables shape-memory hydrogels with pH; enzyme- or an inverse temperature sensitivity %U %X %0 conference lecture %@ %A Liu, Y., Kratz, K., Lendlein, A. %D 2022 %J MRS Spring Meeting 2022 %T Actuating micro-bowls with a temperature-memory %U %X %0 conference lecture %@ %A Farhan, M., Behl, M., Kreatz, K., Lendlein, A. %D 2022 %J MRS Spring Meeting 2022 %T Origami hand for soft robotics driven by thermally controlled polymeric fiber actuators %U %X %0 journal article %@ 1386-0291 %A Ullah, I., Wang, W., Ma, N., Lendlein, A. %D 2022 %J Clinical Hemorheology and Microcirculation %N 3 %P 327-341 %R doi:10.3233/CH-211264 %T Multiblock copolymers type PDC- a family of multifunctional biomaterials for regenerative medicine %U https://doi.org/10.3233/CH-211264 3 %X Multiblock copolymers type PDC are polyetheresterurethanes composed of poly(ɛ-caprolactone) and poly(p-dioxanone) segments. They were designed as degradadable shape-memory polymers for medical devices, which can be implanted minimally-invasively. While providing structural support in the initial phase after implantation, they are capable to modulate soft tissue regeneration while degradation. In this perspective, we elucidate cell-material interactions, compatibility both in-vitro and in-vivo and biofunctionality of PDC, which represents a promising candidate biomaterial family especially for cardiovascular applications. %0 journal article %@ 1999-4923 %A Altabal, O., Wischke, C., Lendlein, A. %D 2022 %J Pharmaceutics %N 12 %P 2611 %R doi:10.3390/pharmaceutics14122611 %T Design of Reservoirs Enabling Stress-Induced Sequential Release Systems %U https://doi.org/10.3390/pharmaceutics14122611 12 %X Mechanical stress is recognized as a principle for opening enclosed compartments through compression, stretching, or shear, eventually resulting in the onset of a diffusion-controlled release. Here, we hypothesized that the geometrical design of cavities (cut-outs) introduced as containers in elastic polymer substrates and sealed with a brittle coating layer would enable a pre-defined release of different compounds by stress concentration phenomena. Design criteria such as cut-out shapes, orientations, and depths were initially assessed for suitably different stress concentrations in computational models. In substrates fabricated from polydimethylsiloxane by photolithographic techniques, the local strains at horizontal rectangular, circular, and vertical rhombus-shaped cut-outs systematically increased under horizontal stretching as proposed. When filled with model compounds and coated with poly(n-butyl cyanoacrylate), a pre-defined induced breakage of the coating and compound release was confirmed upon continuous uniaxial stretching. This proof of concept demonstrates how device design and functions interlink and may motivate further exploration in technology and medicine for deformation-induced on-demand dosage applications. %0 journal article %@ 2667-1093 %A Tarazona, N., Wei, R., Brott, S., Pfaff, L., Bornscheuer, U., Lendlein, A., Machatschek, R. %D 2022 %J Chem Catalysis %N 12 %P 3573-3589 %R doi:10.1016/j.checat.2022.11.004 %T Rapid depolymerization of poly(ethylene terephthalate) thin films by a dual-enzyme system and its impact on material properties %U https://doi.org/10.1016/j.checat.2022.11.004 12 %X Enzymatic hydrolysis holds great promise for plastic waste recycling and upcycling. The interfacial catalysis mode, and the variability of polymer specimen properties under different degradation conditions, add to the complexity and difficulty of understanding polymer cleavage and engineering better biocatalysts. We present a systemic approach to studying the enzyme-catalyzed surface erosion of poly(ethylene terephthalate) (PET) while monitoring/controlling operating conditions in real time with simultaneous detection of mass loss and changes in viscoelastic behavior. PET nanofilms placed on water showed a porous morphology and a thickness-dependent glass transition temperature (Tg) between 40°C and 44°C, which is >20°C lower than the Tg of bulk amorphous PET. Hydrolysis by a dual-enzyme system containing thermostabilized variants of Ideonella sakaiensis PETase and MHETase resulted in a maximum depolymerization of 70% in 1 h at 50°C. We demonstrate that increased accessible surface area, amorphization, and Tg reduction speed up PET degradation while simultaneously lowering the threshold for degradation-induced crystallization. %0 conference lecture %@ %A Lau, S., Gossen, M., Lendlein, A., Jung, F. %D 2022 %J 40. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheologie (DGKMH) %T Differential sensitivity of assays for determining vein endothelial cell senescence %U %X %0 conference poster %@ %A Machatschek, R., Sahabudeen, H., Lendlein, A. %D 2022 %J MRS Spring Meeting 2022 %T In situ mechanical characterization and degradation of 2D MOFs %U %X %0 conference poster %@ %A Ullah, I., Nie, Y., Gossen, M., Kurtz, A., Ma, N., Lendlein, A. %D 2022 %J 40. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheologie e.V. %T A simple approach towards the efficient generation of 3D blood vessels organoids %U %X %0 journal article %@ 2352-9407 %A Sauter, T., Kratz, K., Farhan, M., Heuchel, M., Lendlein, A. %D 2022 %J Applied Materials Today %P 101562 %R doi:10.1016/j.apmt.2022.101562 %T Design and fabrication of fiber mesh actuators %U https://doi.org/10.1016/j.apmt.2022.101562 %X Soft actuator performance can be tuned by chemistry or mechanical manipulation, but this adjustability is limited especially in view of their growing technological relevance. Inspired from textile engineering, we designed and fabricated fiber mesh actuators and introduced new features like anisotropic behavior and soft-tissue like elastic deformability. Design criteria for the meshes are the formation of fiber bundles, the angle between fiber bundles in different stacked layers and covalent crosslinks forming within and between fibers at their interfacial contact areas. Through crosslinking the interfiber bond strength increased from a bond transmitting neither axial nor rotational loads (pin joint) to a bond strength capable of both (welded joint). For non-linear elastic stiffening, stacked fiber bundles with four embracing fibers were created forming microstructural rhombus shapes. Loading the rhombus diagonally allowed generation of “soft tissue”-like mechanics. By adjustment of stacking angles, the point of strong increase in stress is tuned. While the highest stresses are observed in aligned and crosslinked fiber mats along the direction of the fiber, the strongest shape-memory actuation behavior is found in randomly oriented fiber mats. Fiber mesh actuators controlled by temperature are of high significance as soft robot skins and as for active patches supporting tissue regeneration. %0 conference lecture %@ %A Tarazona, N., Machatschek, R., Lendlein, A. %D 2022 %J MRS Spring Meeting 2022 %T Decreasing the glass transition temperature (Tg) of poly(ethylene terephthalate) films at the air-water interface by reducing sample dimensions %U %X %0 journal article %@ 2159-6859 %A Xu, X., Nie, Y., Wang, W., Ma, N., Lendlein, A. %D 2021 %J MRS Communications %N 4 %P 425-431 %R doi:10.1557/s43579-021-00049-5 %T Periodic thermomechanical modulation of toll-like receptor expression and distribution in mesenchymal stromal cells %U https://doi.org/10.1557/s43579-021-00049-5 4 %X Toll-like receptor (TLR) can trigger an immune response against virus including SARS-CoV-2. TLR expression/distribution is varying in mesenchymal stromal cells (MSCs) depending on their culture environments. Here, to explore the effect of periodic thermomechanical cues on TLRs, thermally controlled shape-memory polymer sheets with programmable actuation capacity were created. The proportion of MSCs expressing SARS-CoV-2-associated TLRs was increased upon stimulation. The TLR4/7 colocalization was promoted and retained in the endoplasmic reticula. The TLR redistribution was driven by myosin-mediated F-actin assembly. These results highlight the potential of boosting the immunity for combating COVID-19 via thermomechanical preconditioning of MSCs. %0 journal article %@ 1742-5689 %A Bastola, A., Soffiatti, P., Behl, M., Lendlein, A., Rowe, N. %D 2021 %J Journal of the Royal Society Interface %N 178 %P 20210040 %R doi:10.1098/rsif.2021.0040 %T Structural performance of a climbing cactus: making the most of softness %U https://doi.org/10.1098/rsif.2021.0040 178 %X Climbing plants must reach supports and navigate gaps to colonize trees. This requires a structural organization ensuring the rigidity of so-called ‘searcher’ stems. Cacti have succulent stems adapted for water storage in dry habitats. We investigate how a climbing cactus Selenicereus setaceus develops its stem structure and succulent tissues for climbing. We applied a ‘wide scale’ approach combining field-based bending, tensile and swellability tests with fine-scale rheological, compression and anatomical analyses in laboratory conditions. Gap-spanning ‘searcher’ stems rely significantly on the soft cortex and outer skin of the stem for rigidity in bending (60–94%). A woody core contributes significantly to axial and radial compressive strength (80%). Rheological tests indicated that storage moduli were consistently higher than loss moduli indicating that the mucilaginous cortical tissue behaved like a viscoelastic solid with properties similar to physical or chemical hydrogels. Rheological and compression properties of the soft tissue changed from young to old stages. The hydrogel–skin composite is a multi-functional structure contributing to rigidity in searcher stems but also imparting compliance and benign failure in environmental situations when stems must fail. Soft tissue composites changing in function via changes in development and turgescence have a great potential for exploring candidate materials for technical applications. %0 journal article %@ 1525-7797 %A Folikumah, M., Behl, M., Lendlein, A. %D 2021 %J Biomacromolecules %N 5 %P 1875-1884 %R doi:10.1021/acs.biomac.0c01690 %T Thiol–Thioester Exchange Reactions in Precursors Enable pH-Triggered Hydrogel Formation %U https://doi.org/10.1021/acs.biomac.0c01690 5 %X Bio-interactive hydrogel formation in situ requires sensory capabilities toward physiologically relevant stimuli. Here, we report on pH-controlled in situ hydrogel formation relying on latent cross-linkers, which transform from pH sensors to reactive molecules. In particular, thiopeptolide/thio-depsipeptides were capable of pH-sensitive thiol–thioester exchange reactions to yield α,ω-dithiols, which react with maleimide-functionalized multi-arm polyethylene glycol to polymer networks. Their water solubility and diffusibility qualify thiol/thioester-containing peptide mimetics as sensory precursors to drive in situ localized hydrogel formation with potential applications in tissue regeneration such as treatment of inflamed tissues of the urinary tract. %0 journal article %@ 0884-2914 %A Neffe, A., Zhang, Q., Hommes-Schattmann, P., Wang, W., Xu, X., Ahmad, B., Williams, G., Lendlein, A. %D 2021 %J Journal of Materials Research %N 14 %P 2995-3009 %R doi:10.1557/s43578-021-00260-z %T Functionalizable coaxial PLLA/PDLA nanofibers with stereocomplexes at the internal interface %U https://doi.org/10.1557/s43578-021-00260-z 14 %X Multifunctionality of electrospun polylactic acid (PLA) nonwovens was generated by the morphological design of nanofibers. Coaxial fibers with a lower number average molar mass Mn PLLA core and a higher Mn PDLA shell form PDLA–PLLA stereocrystals at the interface, induced by annealing. In tensile tests under physiological conditions, the core–shell fibers with higher crystallinity (22% compared to 11–14%) had lower Young’s moduli E (9 ± 1 MPa) and lower elongation at break εb (26 ± 3%) than PDLA alone (E = 31 ± 9 MPa, εb = 80 ± 5%), which can be attributed to simultaneous crystallization and relaxation effects. Gelatin incorporated in the PDLA phase was presented on the outer surface providing a biointerface putatively favorable for cell adherence. Gelatin incorporation did not influence the crystallization behavior but slightly lowered Tg (60 → 54 °C). Employing exclusively polymers established in the clinic, multifunctionality was generated by design. %0 journal article %@ 2159-6859 %A Farhan, M., Behl, M., Kratz, K., Lendlein, A. %D 2021 %J MRS Communications %N 4 %P 476-482 %R doi:10.1557/s43579-021-00058-4 %T Origami hand for soft robotics driven by thermally controlled polymeric fiber actuators %U https://doi.org/10.1557/s43579-021-00058-4 4 %X Active fibers can serve as artificial muscles in robotics or components of smart textiles. Here, we present an origami hand robot, where single fibers control the reversible movement of the fingers. A recovery/contracting force of 0.2 N with a work capacity of 0.175 kJ kg−1 was observed in crosslinked poly[ethylene-co-(vinyl acetate)] (cPEVA) fibers, which could enable the bending movement of the fingers by contraction upon heating. The reversible opening of the fingers was attributed to a combination of elastic recovery force of the origami structure and crystallization-induced elongation of the fibers upon cooling. %0 journal article %@ 2059-8521 %A Rodriguez, N., Bastola, A., Behl, M., Soffiatti, P., Rowe, N., Lendlein, A. %D 2021 %J MRS Advances %N 25 %P 625-630 %R doi:10.1557/s43580-021-00081-6 %T Approaches of combining a 3D-printed elastic structure and a hydrogel to create models for plant-inspired actuators %U https://doi.org/10.1557/s43580-021-00081-6 25 %X Inspired by the interesting functional traits of a climbing cactus, Selenicereus setaceus, found in the forest formations of Southeastern Brazil, we formulated a hypothesis that we can directly learn from the plants to develop multi-functional artificial systems by means of a multi-disciplinary approach. In this context, our approach is to take advantage of 3D-printing techniques and shape-memory hydrogels synergistically to mimic the functional traits of the cactus. This work reports on the preliminary investigation of cactus-inspired artificial systems. First, we 3D-printed soft polymeric materials and characterized them, which defines the structure and is a passive component of a multi-material system. Second, different hydrogels were synthesized and characterized, which is an active component of a multi-material system. Finally, we investigated how the hydrogel can be integrated into the 3D-printed constructs to develop artificial functional systems. %0 journal article %@ 2059-8521 %A Izraylit, V., Heuchel, M., Kratz, K., Lendlein, A. %D 2021 %J MRS Advances %N 33 %P 781-785 %R doi:10.1557/s43580-021-00063-8 %T Non-woven shape-memory polymer blend actuators %U https://doi.org/10.1557/s43580-021-00063-8 33 %X The hierarchical design approach provides various opportunities to adjust the structural performance of polymer materials. Electrospinning processing techniques give access to molecular orientation as a design parameter, which we consider here in view of the shape-memory actuation performance. The aim of this work is to investigate how the reversible strain ε′rev can be affected by a morphology change from a bulk material to an electrospun mesh. ε′rev could be increased from 5.5 ± 0.5% to 15 ± 1.8% for a blend from a multiblock copolymer with poly(ε-caprolactone) (PCL) and poly(L-lactide) (PLLA) segments with oligo(D-lactide) (ODLA). This study demonstrates an effective design approach for enhancing soft actuator performance, which can be broadly applied in soft robotics and medicine. %0 journal article %@ 2159-6859 %A Folikumah, M., Behl, M., Lendlein, A. %D 2021 %J MRS Communications %N 4 %P 402-410 %R doi:10.1557/s43579-021-00041-z %T Reaction behaviour of peptide-based single thiol-thioesters exchange reaction substrate in the presence of externally added thiols %U https://doi.org/10.1557/s43579-021-00041-z 4 %X Identification of patterns in chemical reaction pathways aids in the effective design of molecules for specific applications. Here, we report on model reactions with a water-soluble single thiol-thioester exchange (TTE) reaction substrate, which was designed taking in view biological and medical applications. This substrate consists of the thio-depsipeptide, Ac-Pro-Leu-Gly-SLeu-Leu-Gly-NEtSH (TDP) and does not yield foul-smelling thiol exchange products when compared with aromatic thiol containing single TTE substrates. TDP generates an α,ω-dithiol crosslinker in situ in a ‘pseudo intramolecular’ TTE. Competitive intermolecular TTE of TDP with externally added “basic” thiols increased the crosslinker concentration whilst “acidic” thiols decreased its concentration. TDP could potentially enable in situ bioconjugation and crosslinking applications. %0 journal article %@ 2059-8521 %A Liang, X., Behl, M., Luetzow, K., Lendlein, A. %D 2021 %J MRS Advances %P 764-768 %R doi:10.1557/s43580-021-00082-5 %T Cooligomers from morpholine-2,5-dione and para-dioxanone and catalyst complex SnOct2/2-hydroxyethyl sulfide %U https://doi.org/10.1557/s43580-021-00082-5 %X Complexes from catalysts and initiator can be used to insert a specific number of additional chemical functional groups in (co)polymers prepared by ring-opening polymerization (ROP) of lactones. We report on the synthesis of cooligomers from sec-butyl-morpholine-2,5-dione (SBMD) and para-dioxanone (PDX) by ROP with varied feed ratios in the bulk using the catalyst complex SnOct2/2-hydroxyethyl sulfide. Mn of the cooligomers (determined by GPC) decreased with decreasing SBMD feed ratio from 4200 ± 420 to 800 ± 80 g mol−1. When the feed ratio was reduced from 80 to 50 mol% the molar ratio of SBMD of the cooligomers (determined by 1H-NMR) remained nearly unchanged between 81 and 86 mol% and was attributed to a higher reactivity of SBMD. This assumption was confirmed by fractionation of GPC, in which an increase of SBMD with increasing molecular weight was observed. The catalyst/initiator system provides a high potential to create orthogonal building blocks by cleavage of the sulfide bond. %0 journal article %@ 2159-6859 %A Bäckemo, J., Liu, Y., Lendlein, A. %D 2021 %J MRS Communications %N 4 %P 462-469 %R doi:10.1557/s43579-021-00056-6 %T Bio-inspired and computer-supported design of modulated shape changes in polymer materials %U https://doi.org/10.1557/s43579-021-00056-6 4 %X The Venus flytrap is a fascinating plant with a finely tuned mechanical bi-stable system, which can switch between mono- and bi-stability. Here, we combine geometrical design of compliant mechanics and the function of shape-memory polymers to enable switching between bi- and mono-stable states. Digital design and modelling using the Chained Beam Constraint Model forecasted two geometries, which were experimentally realized as structured films of cross-linked poly[ethylene-co-(vinyl acetate)] supported by digital manufacturing. Mechanical evaluation confirmed our predicted features. We demonstrated that a shape-memory effect could switch between bi- and mono-stability for the same construct, effectively imitating the Venus flytrap. %0 journal article %@ 1386-0291 %A Xu, X., Nie, Y., Wang, W., Ullah, I., Tung, W., Ma, N., Lendlein, A. %D 2021 %J Clinical Hemorheology and Microcirculation %N 1 %P 217-230 %R doi:10.3233/CH-219111 %T Generation of 2.5D lung bud organoids from human induced pluripotent stem cells %U https://doi.org/10.3233/CH-219111 1 %X Human induced pluripotent stem cells (hiPSCs) are a promising cell source to generate the patient-specific lung organoid given their superior differentiation potential. However, the current 3D cell culture approach is tedious and time-consuming with a low success rate and high batch-to-batch variability. Here, we explored the establishment of lung bud organoids by systematically adjusting the initial confluence levels and homogeneity of cell distribution. The efficiency of single cell seeding and clump seeding was compared. Instead of the traditional 3D culture, we established a 2.5D organoid culture to enable the direct monitoring of the internal structure via microscopy. It was found that the cell confluence and distribution prior to induction were two key parameters, which strongly affected hiPSC differentiation trajectories. Lung bud organoids with positive expression of NKX 2.1, in a single-cell seeding group with homogeneously distributed hiPSCs at 70% confluence (SC_70%_hom) or a clump seeding group with heterogeneously distributed cells at 90% confluence (CL_90%_het), can be observed as early as 9 days post induction. These results suggest that a successful lung bud organoid formation with single-cell seeding of hiPSCs requires a moderate confluence and homogeneous distribution of cells, while high confluence would be a prominent factor to promote the lung organoid formation when seeding hiPSCs as clumps. 2.5D organoids generated with defined culture conditions could become a simple, efficient, and valuable tool facilitating drug screening, disease modeling and personalized medicine. %0 journal article %@ 0884-2914 %A Machatschek, R., Heuchel, M., Lendlein, A. %D 2021 %J Journal of Materials Research %N 14 %P 2987-2994 %R doi:10.1557/s43578-021-00267-6 %T Hydrolytic stability of polyetherimide investigated in ultrathin films %U https://doi.org/10.1557/s43578-021-00267-6 14 %X Increasing the surface hydrophilicity of polyetherimide (PEI) through partial hydrolysis of the imide groups while maintaining the length of the main-chain was explored for adjusting its function in biomedical and membrane applications. The outcome of the polymer analogous reaction, i.e., the degree of ring opening and chain cleavage, is difficult to address in bulk and microstructured systems, as these changes only occur at the interface. Here, the reaction was studied at the air–water interface using the Langmuir technique, assisted by atomic force microscopy and vibrational spectroscopy. Slow PEI hydrolysis sets in at pH > 12. At pH = 14, the ring opening is nearly instantaneous. Reduction of the layer viscosity with time at pH = 14 suggested moderate chain cleavage. No hydrolysis was observed at pH = 1. Hydrolyzed PEI films had a much more cohesive structure, suggesting that the nanoporous morphology of PEI can be tuned via hydrolysis. %0 journal article %@ 2059-8521 %A Deng, Z., Wang, W., Xu, X., Ma, N., Lendlein, A. %D 2021 %J MRS Advances %P 739-744 %R doi:10.1557/s43580-021-00091-4 %T Polydopamine-based biofunctional substrate coating promotes mesenchymal stem cell migration %U https://doi.org/10.1557/s43580-021-00091-4 %X Rapid migration of mesenchymal stem cells (MSCs) on device surfaces could support in vivo tissue integration and might facilitate in vitro organoid formation. Here, polydopamine (PDA) is explored as a biofunctional coating to effectively promote MSC motility. It is hypothesized that PDA stimulates fibronectin deposition and in this way enhances integrin-mediated migration capability. The random and directional cell migration was investigated by time-lapse microscopy and gap closure assay respectively, and analysed with softwares as computational tools. A higher amount of deposited fibronectin was observed on PDA substrate, compared to the non-coated substrate. The integrin β1 activation and focal adhesion kinase (FAK) phosphorylation at Y397 were enhanced on PDA substrate, but the F-actin cytoskeleton was not altered, suggesting MSC migration on PDA was regulated by integrin initiated FAK signalling. This study strengthens the biofunctionality of PDA coating for regulating stem cells and offering a way of facilitating tissue integration of devices. %0 journal article %@ 0884-2914 %A Friess, F., Lendlein, A., Wischke, C. %D 2021 %J Journal of Materials Research %P 3248-3257 %R doi:10.1557/s43578-021-00295-2 %T Size control of shape switchable micronetworks by fast two-step microfluidic templating %U https://doi.org/10.1557/s43578-021-00295-2 %X Shape-memory polymer micronetworks (MN) are micrometer-sized objects that can switch their outer shape upon external command. This study aims to scale MN sizes to the low micrometer range at very narrow size distributions. In a two-step microfluidic strategy, the specific design of coaxial class capillary devices allowed stabilizing the thread of the dispersed phase to efficiently produce precursor particles in the tip-streaming regime at rates up to ~ 170 kHz and final sizes down to 4 µm. In a subsequent melt-based microfluidic photocrosslinking of the methacrylate-functionalized oligo(ɛ-caprolactone) precursor material, MN could be produced without particle aggregation. A comprehensive analysis of MN properties illustrated successful crosslinking, semi-crystalline morphology, and a shape-switching functionality for all investigated MN sizes (4, 6, 9, 12, 22 µm). Such functional micronetworks tailored to and below the dimension of cells can enable future applications in technology and medicine like controlling cell interaction. %0 journal article %@ 2399-7532 %A Sahabudeen, H., Machatschek, R., Lendlein, A. %D 2021 %J Multifunctional Materials %N 4 %P 042001 %R doi:10.1088/2399-7532/ac1e7d %T Multifunctionality as design principle for contact lens materials %U https://doi.org/10.1088/2399-7532/ac1e7d 4 %X From synthesis through storage to disposal, contact lenses (CLs) interact with different system environments throughout their functional life cycle. To fulfill their therapeutic purpose, they need to exhibit a distinct behavior in each of them, which is achieved through a combination of different material functions. As such, CL materials are a showcase of highly advanced and mass-produced multifunctional biomaterials. Their great relevance and long history mean that a vast amount of work has gone into the implementation of ever more advanced functions. From understanding the approaches used to achieve multifunctionality in CLs, a lot of inspiration for the design of other multifunctional medical devices can be drawn. Therefore, here, we provide a systematic overview of the different functions that are combined in today's CL materials, together with their quantification methods, chemical design principles and fabrication techniques. We further provide an outlook on the functions that are currently under investigation for the next generation of commercial CLs. %0 journal article %@ 2059-8521 %A Nie, Y., Wang, W., Xu, X., Ma, N., Lendlein, A. %D 2021 %J MRS Advances %P 745-749 %R doi:10.1557/s43580-021-00110-4 %T The response of human induced pluripotent stem cells to cyclic temperature changes explored by BIO-AFM %U https://doi.org/10.1557/s43580-021-00110-4 %X Human induced pluripotent stem cells (hiPSCs) are highly sensitive to extrinsic physical and biochemical signals from their extracellular microenvironments. In this study, we analyzed the effect of cyclic temperature changes on hiPSCs behaviors, especially by means of scanning force microscopy (BIO-AFM). The alternation in cellular mechanics, as well as the secretion and pattern of deposition of extracellular matrix (ECM) protein in hiPSCs were evaluated. The arrangement of the actin cytoskeleton changed with the variation of the temperature. The rearranged cytoskeleton architecture led to the subsequent changes in cell mechanics (Young's modulus of hiPSCs). With the exposure to the cyclic cold stimuli, an increase in the average surface roughness (Ra) and roughness mean square (RMS) was detected. This observation might be at least in part due to the upregulated secretion of Laminin α5 during repeated temporary cooling. The expression of pluripotent markers, NANOG and SOX2, was not impaired in hiPSCs, when exposed to the cyclic cold stimuli for 24 h. Our findings provide an insight into the effect of temperature on the hiPSC behaviors, which may contribute to a better understanding of the application of locally controlled therapeutic hypothermia. %0 journal article %@ 2159-6859 %A Lau, S., Liu, Y., Maier, A., Braune, S., Gossen, M., Neffe, A., Lendlein, A. %D 2021 %J MRS Communications %N 5 %P 559-567 %R doi:10.1557/s43579-021-00072-6 %T Establishment of an in vitro thrombogenicity test system with cyclic olefin copolymer substrate for endothelial layer formation %U https://doi.org/10.1557/s43579-021-00072-6 5 %X In vitro thrombogenicity test systems require co-cultivation of endothelial cells and platelets under blood flow-like conditions. Here, a commercially available perfusion system is explored using plasma-treated cyclic olefin copolymer (COC) as a substrate for the endothelial cell layer. COC was characterized prior to endothelialization and co-cultivation with platelets under static or flow conditions. COC exhibits a low roughness and a moderate hydrophilicity. Flow promoted endothelial cell growth and prevented platelet adherence. These findings show the suitability of COC as substrate and the importance of blood flow-like conditions for the assessment of the thrombogenic risk of drugs or cardiovascular implant materials. %0 conference lecture (invited) %@ %A Izraylit, V., Kratz, K., Heuchel, M., Lendlein, A. %D 2021 %J Seminar am Kurchatov Complex of NBICS-nature-like Technologies; National Research Centre Kurchatov Institute %T Shape-memory actuator blends by stereocomplexation of PLA %U %X %0 editorial %@ 0014-3057 %A van Bochove, B., Grijpma, D., Lendlein, A., Seppälä, J. %D 2021 %J European Polymer Journal %P 110573 %R doi:10.1016/j.eurpolymj.2021.110573 %T Designing advanced functional polymers for medicine %U https://doi.org/10.1016/j.eurpolymj.2021.110573 %X %0 conference poster %@ %A Folikumah, M., Behl, M., Lendlein, A. %D 2021 %J 2021 Virtual MRS Spring Meeting %T A peptide based latent crosslinker activated by thiol-thioester exchange reaction %U %X %0 journal article %@ 1422-0067 %A Lau, S., Maier, A., Braune, S., Gossen, M., Lendlein, A. %D 2021 %J International Journal of Molecular Sciences %N 13 %P 7006 %R doi:10.3390/ijms22137006 %T Effect of Endothelial Culture Medium Composition on Platelet Responses to Polymeric Biomaterials %U https://doi.org/10.3390/ijms22137006 13 %X Near-physiological in vitro thrombogenicity test systems for the evaluation of blood-contacting endothelialized biomaterials requires co-cultivation with platelets (PLT). However, the addition of PLT has led to unphysiological endothelial cell (EC) detachment in such in vitro systems. A possible cause for this phenomenon may be PLT activation triggered by the applied endothelial cell medium, which typically consists of basal medium (BM) and nine different supplements. To verify this hypothesis, the influence of BM and its supplements was systematically analyzed regarding PLT responses. For this, human platelet rich plasma (PRP) was mixed with BM, BM containing one of nine supplements, or with BM containing all supplements together. PLT adherence analysis was carried out in six-channel slides with plasma-treated cyclic olefin copolymer (COC) and poly(tetrafluoro ethylene) (PTFE, as a positive control) substrates as part of the six-channel slides in the absence of EC and under static conditions. PLT activation and aggregation were analyzed using light transmission aggregometry and flow cytometry (CD62P). Medium supplements had no effect on PLT activation and aggregation. In contrast, supplements differentially affected PLT adherence, however, in a polymer- and donor-dependent manner. Thus, the use of standard endothelial growth medium (BM + all supplements) maintains functionality of PLT under EC compatible conditions without masking the differences of PLT adherence on different polymeric substrates. These findings are important prerequisites for the establishment of a near-physiological in vitro thrombogenicity test system assessing polymer-based cardiovascular implant materials in contact with EC and PLT. %0 journal article %@ 1386-0291 %A Zhou, S., Di Luca, M., Xu, X., Ma, N., Jung, F., Lendlein, A. %D 2021 %J Clinical Hemorheology and Microcirculation %N 4 %P 609-623 %R doi:10.3233/CH-211250 %T Defeating antibiotic-resistant bacteria with protein-resistant polyGGE film %U https://doi.org/10.3233/CH-211250 4 %X Biofouling on medical device surfaces, which is initiated by protein adsorption and adhesion of microbes especially the antibiotic-resistant bacteria, attracts global attention for centuries due to its enduring challenges in healthcare. Here, the antifouling effect of hydrophilic poly(glycerol glycidyl ether) (polyGGE) film is explored in comparison to hemocompatible and protein-resistant control polymers. The chemical and thermomechanical stability of polyGGE in hydrated conditions at body temperature was achieved via adjusting UV curing and KOH quenching time. The polyGGE surface is inert to the plasma protein adsorption and interfered the metabolism conditions, biofilm formation and growth of both Gram negative (Gram–) and antibiotic-resistant Gram positive (Gram+) bacteria. These results indicate the potential application of polyGGE for combating the risk of hospital-acquired infections and preventing drug-resistant superbug spreading. %0 journal article %@ 1386-0291 %A Zhou, S., Xu, X., Ma, N., Jung, F., Lendlein, A. %D 2021 %J Clinical Hemorheology and Microcirculation %N 4 %P 597-608 %R doi:10.3233/CH-211241 %T Influence of sterilization conditions on sulfate-functionalized polyGGE %U https://doi.org/10.3233/CH-211241 4 %X Sulfated biomolecules are known to influence numerous biological processes in all living organisms. Particularly, they contribute to prevent and inhibit the hypercoagulation condition. The failure of polymeric implants and blood contacting devices is often related to hypercoagulation and microbial contamination. Here, bioactive sulfated biomacromolecules are mimicked by sulfation of poly(glycerol glycidyl ether) (polyGGE) films. Autoclaving, gamma-ray irradiation and ethylene oxide (EtO) gas sterilization techniques were applied to functionalized materials. The sulfate group density and hydrophilicity of sulfated polymers were decreased while chain mobility and thermal degradation were enhanced post autoclaving when compared to those after EtO sterilization. These results suggest that a quality control after sterilization is mandatory to ensure the amount and functionality of functionalized groups are retained. %0 conference lecture %@ %A Liang, X., Behl, M., Lendlein, A. %D 2021 %J Virtual MRS Spring Meeting %T Teroligomers from Morpholine-2;5-Diones providing a large variety of repeating unit sequences %U %X %0 journal article %@ 1944-8244 %A Deng, Z., Wang, W., Xu, X., Nie, Y., Liu, Y., Gould, O., Ma, N., Lendlein, A. %D 2021 %J ACS Applied Materials and Interfaces %N 9 %P 10748-10759 %R doi:10.1021/acsami.0c22565 %T Biofunction of Polydopamine Coating in Stem Cell Culture %U https://doi.org/10.1021/acsami.0c22565 9 %X High levels of reactive oxygen species (ROS) during stem cell expansion often lead to replicative senescence. Here, a polydopamine (PDA)-coated substrate was used to scavenge extracellular ROS for mesenchymal stem cell (MSC) expansion. The PDA-coated substrate could reduce the oxidative stress and mitochondrial damage in replicative senescent MSCs. The expression of senescence-associated β-galactosidase of MSCs from three human donors (both bone marrow- and adipose tissue-derived) was suppressed on PDA. The MSCs on the PDA-coated substrate showed a lower level of interleukin 6 (IL-6), one of the senescence-associated inflammatory components. Cellular senescence-specific genes, such as p53 and p21, were downregulated on the PDA-coated substrate, while the stemness-related gene, OCT4, was upregulated. The PDA-coated substrate strongly promoted the proliferation rate of MSCs, while the stem cell character and differentiation potential were retained. Large-scale expansion of stem cells would greatly benefit from the PDA-coated substrate. %0 conference lecture (invited) %@ %A Kratz, K., Izraylit, V., Heuchel, M., Lendlein, A. %D 2021 %J Virtual MRS Spring Meeting 2021 %T Shape-memory actuator blends by stereocomplexation of PLA %U %X %0 journal article %@ 0014-3057 %A Behl, M., Balk, M., Lützow, K., Lendlein, A. %D 2021 %J European Polymer Journal %P 110207 %R doi:10.1016/j.eurpolymj.2020.110207 %T Impact of block sequence on the phase morphology of multiblock copolymers obtained by high-throughput robotic synthesis %U https://doi.org/10.1016/j.eurpolymj.2020.110207 %X The chemical nature, the number length of integrated building blocks, as well as their sequence structure impact the phase morphology of multiblock copolymers (MBC) consisting of two non-miscible block types. We hypothesized that a strictly alternating sequence should favour phase segregation and in this way the elastic properties. A library of well-defined MBCs composed of two different hydrophobic, semi-crystalline blocks providing domains with well-separated melting temperatures (Tms) were synthesized from the same type of precursor building blocks as strictly alternating (MBCsalt) or random (MBCsran) MBCs and compared. Three different series of MBCsalt or MBCsran were synthesized by high-throughput synthesis by coupling oligo(ε-caprolactone) (OCL) of different molecular weights (2, 4, and 8 kDa) with oligotetrahydrofuran (OTHF, 2.9 kDa) via Steglich esterification in which the molar ratio of the reaction partners was slightly adjusted. Maximum of weight average molecular weight (Mw) were 65,000 g∙mol−1, 165,000 g∙mol−1, and 168,000 g∙mol−1 for MBCsalt and 80,500 g∙mol−1, 100,000 g∙mol−1, and 147,600 g∙mol−1 for MBCsran. When Mw increased, a decrease of both Tms associated to the melting of the OCL and OTHF domains was observed for all MBCs. Tm (OTHF) of MBCsran was always higher than Tm (OTHF) of MBCsalt, which was attributed to a better phase segregation. In addition, the elongation at break of MBCsalt was almost half as high when compared to MBCsran. In this way this study elucidates role of the block length and sequence structure in MBCs and enables a quantitative discussion of the structure-function relationship when two semi-crystalline block segments are utilized for the design of block copolymers. %0 conference lecture %@ %A Xu, X., Wang, W., Nie, Y., Ma, N., Lendlein, A. %D 2021 %J 2021 Virtual MRS Spring Meeting %T Thermomechanical modulation of Toll-like receptor internalization and expression profile in mesenchymal stromal cells %U %X %0 journal article %@ 1438-7492 %A Farhan, M., Chaudhary, D., Nöchel, U., Behl, K., Kratz, K., Lendlein, A. %D 2021 %J Macromolecular Materials and Engineering %N 2 %P 2000579 %R doi:10.1002/mame.202000579 %T Electrical Actuation of Coated and Composite Fibers Based on Poly[ethylene‐co‐(vinyl acetate)] %U https://doi.org/10.1002/mame.202000579 2 %X Robots are typically controlled by electrical signals. Resistive heating is an option to electrically trigger actuation in thermosensitive polymer systems. In this study electrically triggerable poly[ethylene‐co‐(vinyl acetate)] (PEVA)‐based fiber actuators are realized as composite fibers as well as polymer fibers with conductive coatings. In the coated fibers, the core consists of crosslinked PEVA (cPEVA), while the conductive coating shell is achieved via a dip coating procedure with a coating thickness between 10 and 140 µm. The conductivity of coated fibers σ = 300–550 S m−1 is much higher than that of the composite fibers σ = 5.5 S m−1. A voltage (U) of 110 V is required to heat 30 cm of coated fiber to a targeted temperature of ≈ 65 °C for switching in less than a minute. Cyclic electrical actuation investigations reveal ε′rev = 5 ± 1% reversible change in length for coated fibers. The fabrication of such electro‐conductive polymeric actuators is suitable for upscaling so that their application potential as artificial muscles can be explored in future studies. %0 journal article %@ 0014-3057 %A Neffe, A., Garcia Cruz, D., Roch, T., Lendlein, A. %D 2021 %J European Polymer Journal %P 110148 %R doi:10.1016/j.eurpolymj.2020.110148 %T Microparticles from glycidylmethacrylated gelatin as cell carriers prepared in an aqueous two-phase system %U https://doi.org/10.1016/j.eurpolymj.2020.110148 %X Encapsulation by polymeric biomaterials can provide mechanical protection of cells and shielding from the immune system of the host when implanted as cell therapy. At the same time, free exchange of nutrients and metabolites including bioactive molecules guiding regenerative processes is facilitated. Here, glycidylmethacrylated gelatin (GMA-gelatin) is explored as matrix material for adherent (L929 mouse fibroblasts) or non-adherent (Ramos blue) cells by an integrated process of shaping and chemical crosslinking. Microparticle formation was driven by a water-in-water-emulsion technique, which allowed simultaneous irradiation with light of 365 nm in the presence of the photosensitizer irgacure 2959. Suitable photopolymerization conditions were determined in experiments with GMA-gelatin and cells. More than 85% of the cells survived this procedure, and an encapsulation efficiency of up to 75 ± 2% was reached. Diffusivity of molecules up to a molar mass of 150 kg·mol−1 in the matrix was shown by the release of co-encapsulated FITC-labelled dextran. L929 as well as Ramos blue cells proliferated in the microparticle matrix after encapsulation and released enzymes that could be detected in the cell culture medium in an active form. L929 showed the ability to escape the particles over time. Altogether, the presented cell encapsulation system based on a material that is stable to hydrolytic degradation for several weeks is generally suitable for cell based therapy or in vitro test systems. %0 journal article %@ 1438-7492 %A Behl, M., Balk, M., Mansfeld, U., Lendlein, A. %D 2021 %J Macromolecular Materials and Engineering %N 3 %P 2000672 %R doi:10.1002/mame.202000672 %T Phase Morphology of Multiblock Copolymers Differing in Sequence of Blocks %U https://doi.org/10.1002/mame.202000672 3 %X The chemical nature, the number length of integrated building blocks, as well as their sequence structure impact the phase morphology of multiblock copolymers (MBC) consisting of two non‐miscible block types. It is hypothesized that a strictly alternating sequence should impact phase segregation. A library of well‐defined MBC obtained by coupling oligo(ε‐caprolactone) (OCL) of different molecular weights (2, 4, and 8 kDa) with oligotetrahydrofuran (OTHF, 2.9 kDa) via Steglich esterification results in strictly alternating (MBCalt) or random (MBCran) MBC. The three different series has a weight average molecular weight (Mw) of 65 000, 165 000, and 168 000 g mol−1 for MBCalt and 80 500, 100 000, and 147 600 g mol−1 for MBCran. When the chain length of OCL building blocks is increased, the tendency for phase segregation is facilitated, which is attributed to the decrease in chain mobility within the MBC. Furthermore, it is found that the phase segregation disturbs the crystallization by causing heterogeneities in the semi‐crystalline alignment, which is attributed to an increase of the disorder of the OCL semi‐crystalline alignment. %0 journal article %@ 0014-3057 %A Liang, X., Behl, M., Lendlein, A. %D 2021 %J European Polymer Journal %P 110189 %R doi:10.1016/j.eurpolymj.2020.110189 %T Dihydroxy terminated teroligomers from morpholine-2,5-diones %U https://doi.org/10.1016/j.eurpolymj.2020.110189 %X Oligodepsipeptides (ODPs) attract increasing attention as degradable materials in controlled drug delivery or as building blocks for nano-carriers. Their strong intermolecular interactions provide high stability. Tailoring the side groups of the amino acid repeating units to achieve a strong affinity to particular drugs allows a high drug-loading capacity. Here we describe synthesis and characterization of dihydroxy terminated teroligodepsipeptides (ter-ODPs) by ring-opening copolymerization (ROP) of three different morpholine-2,5-diones (MDs) in bulk in order to provide a set of teroligomers with structural variation for drug release or transfection. Ter-ODPs with equivalent co-monomer feed ratios were prepared as well as ter-ODPs, in which the co-monomer feed ratio was varied between 9 mol% and 78 mol%. Ter-ODPs were synthesized by ROP using 1,1,10,10-tetra-n-butyl-1,10-distanna-2,9,11,18-tetraoxa-5,6,14,15-tetrasulfur-cyclodecane (tin(IV) alkoxide) that was obtained by the reaction of dibutyl tin(II) oxide with 2-hydroxyethyl disulfide. The number average molecular weight (Mn) of ter-ODPs, determined by 1H NMR and gel permeation chromatography (GPC), ranged between 4000 g·mol−1 and 8600 g·mol−1. Co-monomer compositions in ter-ODPs could be controlled by changing the feed ratio of co-monomers as observed by 1H NMR spectroscopy and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The amount of remaining monomers as determined by 1H NMR could be kept below 1 wt%. Macrocycles as main sources of byproducts as determined from MALDI-TOF-MS measurements were significantly lower as compared to polymerization by Sn(Oct)2. Glass-transition temperature (Tg) of ter-ODPs ranged between 59 °C and 70 °C. %0 journal article %@ 1022-1352 %A Zhang, P., Rešetic, A., Behl, M., Lendlein, A. %D 2021 %J Macromolecular Chemistry and Physics %N 3 %P 2000394 %R doi:10.1002/macp.202000394 %T Multifunctionality in Polymer Networks by Dynamic of Coordination Bonds %U https://doi.org/10.1002/macp.202000394 3 %X The need for multifunctional materials is driven by emerging technologies and innovations, such as in the field of soft robotics and tactile or haptic systems, where minimizing the number of operational components is not only desirable, but can also be essential for realizing such devices. This study report on designing a multifunctional soft polymer material that can address a number of operating requirements such as solvent resistance, reshaping ability, self‐healing capability, fluorescence stimuli‐responsivity, and anisotropic structural functions. The numerous functional abilities are associated to rhodium(I)–phosphine coordination bonds, which in a polymer network act with their dynamic and non‐covalently bonded nature as multifunctional crosslinks. Reversible aggregation of coordination bonds leads to changes in fluorescence emission intensity that responds to chemical or mechanical stimuli. The fast dynamics and diffusion of rhodium–phosphine ions across and through contacting areas of the material provide for reshaping and self‐healing abilities that can be further exploited for assembly of multiple pieces into complex forms, all without any loss to material‐sensing capabilities. %0 journal article %@ 1386-0291 %A Braune, S., Bäckemo, J., Lau, S., Heuchel, M., Kratz, K., Jung, F., Reinthaler, M., Lendlein, A. %D 2021 %J Clinical Hemorheology and Microcirculation %N 4 %P 367-380 %R doi:10.3233/CH-201029 %T The influence of different rewetting procedures on the thrombogenicity of nanoporous poly(ether imide) microparticles %U https://doi.org/10.3233/CH-201029 4 %X Nanoporous microparticles prepared from poly(ether imide) (PEI) are discussed as candidate adsorber materials for the removal of uremic toxins during apheresis. Polymers exhibiting such porosity can induce the formation of micro-gas/air pockets when exposed to fluids. Such air presenting material surfaces are reported to induce platelet activation and thrombus formation. Physical or chemical treatments prior to implantation are discussed to reduce the formation of such gas nuclei. Here, we report about the influence of different rewetting procedures – as chemical treatments with solvents – on the thrombogenicity of hydrophobic PEI microparticles and PEI microparticles hydrophilized by covalent attachment of poly(vinyl pyrrolidone) (PVP) of two different chain lengths. Autoclaved dry PEI particles of all types with a diameter range of 200 – 250 μm and a porosity of about 84% ±2% were either rewetted directly with phosphate buffered saline (24 h) or after immersion in an ethanol-series. Thrombogenicity of the particles was studied in vitro using human sodium citrated whole blood (60 min, 5 rpm vertical rotation). Numbers of non-adherent platelets were quantified, and adhesion of blood cells was qualitatively analyzed by bright field microscopy. Platelet activation (percentage of CD62P positive platelets and amounts of soluble P-Selectin) and platelet function (PFA100 closure times) were analysed. Retention of blood platelets on the particles was similar for all particle types and both rewetting procedures. Non-adherent platelets were less activated after contact with ethanol-treated particles of all types compared to those rewetted with phosphate buffered saline as assessed by a reduced number of CD62P-positive platelets and reduced amounts of secreted P-Selectin (P < 0.05 each). Interestingly, the hydrophilic surfaces significantly increased the number of activated platelets compared to hydrophobic PEI regardless of the rewetting agent. This suggests that, apart from wettability, other material properties might be more important to regulate platelet activation. PFA100 closure times were reduced and within the reference ranges in the ethanol group, however, significantly increased in the saline group. No substantial difference was detected between the tested surface modifications. In summary, rewetting with ethanol resulted in a reduced thrombogenicity of all studied microparticles regardless of their wettability, most likely resulting from the evacuation of air from the nanoporous particles. %0 conference lecture %@ %A Farhan, M., Rešetič, A., Bastola, A., Behl, M., Lendlein, A. %D 2021 %J 2021 Virtual MRS Spring Meeting %T Artificial tendrils mimicking plant movements by mismatching modulus and length in multimaterial polymeric systems %U %X %0 journal article %@ 2196-7350 %A Machatschek, R., Saretia, S., Lendlein, A. %D 2021 %J Advanced Materials Interfaces %N 6 %P 2001926 %R doi:10.1002/admi.202001926 %T Assessing the Influence of Temperature‐Memory Creation on the Degradation of Copolyesterurethanes in Ultrathin Films %U https://doi.org/10.1002/admi.202001926 6 %X Copolyesterurethanes (PDLCLs) based on oligo(ε‐caprolactone) (OCL) and oligo(ω‐pentadecalactone) (OPDL) segments are biodegradable thermoplastic temperature‐memory polymers. The temperature‐memory capability in these polymers with crystallizable control units is implemented by a thermomechanical programming process causing alterations in the crystallite arrangement and chain organization. These morphological changes can potentially affect degradation. Initial observations on the macroscopic level inspire the hypothesis that switching of the controlling units causes an accelerated degradation of the material, resulting in programmable degradation by sequential coupling of functions. Hence, detailed degradation studies on Langmuir films of a PDLCL with 40 wt% OPDL content are carried out under enzymatic catalysis. The temperature‐memory creation procedure is mimicked by compression at different temperatures. The evolution of the chain organization and mechanical properties during the degradation process is investigated by means of polarization‐modulated infrared reflection absorption spectroscopy, interfacial rheology and to some extend by X‐ray reflectivity. The experiments on PDLCL Langmuir films imply that degradability is not enhanced by thermal switching, as the former depends on the temperature during cold programming. Nevertheless, the thin film experiments show that the leaching of OCL segments does not induce further crystallization of the OPDL segments, which is beneficial for a controlled and predictable degradation. %0 journal article %@ 1422-0067 %A Lau, S., Gossen, M., Lendlein, A., Jung, F. %D 2021 %J International Journal of Molecular Sciences %N 2 %P 978 %R doi:10.3390/ijms22020978 %T Venous and Arterial Endothelial Cells from Human Umbilical Cords: Potential Cell Sources for Cardiovascular Research %U https://doi.org/10.3390/ijms22020978 2 %X Although cardiovascular devices are mostly implanted in arteries or to replace arteries, in vitro studies on implant endothelialization are commonly performed with human umbilical cord-derived venous endothelial cells (HUVEC). In light of considerable differences, both morphologically and functionally, between arterial and venous endothelial cells, we here compare HUVEC and human umbilical cord-derived arterial endothelial cells (HUAEC) regarding their equivalence as an endothelial cell in vitro model for cardiovascular research. No differences were found in either for the tested parameters. The metabolic activity and lactate dehydrogenase, an indicator for the membrane integrity, slightly decreased over seven days of cultivation upon normalization to the cell number. The amount of secreted nitrite and nitrate, as well as prostacyclin per cell, also decreased slightly over time. Thromboxane B2 was secreted in constant amounts per cell at all time points. The Von Willebrand factor remained mainly intracellularly up to seven days of cultivation. In contrast, collagen and laminin were secreted into the extracellular space with increasing cell density. Based on these results one might argue that both cell types are equally suited for cardiovascular research. However, future studies should investigate further cell functionalities, and whether arterial endothelial cells from implantation-relevant areas, such as coronary arteries in the heart, are superior to umbilical cord-derived endothelial cells. %0 journal article %@ 2196-7350 %A Saretia, S., Machatschek, R., Bhuvanesh, T., Lendlein, A. %D 2021 %J Advanced Materials Interfaces %N 7 %P 2001940 %R doi:10.1002/admi.202001940 %T Effect of Water on Crystallization and Melting of Telechelic Oligo(ε‐caprolactone)s in Ultrathin Films %U https://doi.org/10.1002/admi.202001940 7 %X The thermal behavior of ultrathin, semi‐crystalline films of oligo(ε‐caprolactone)s (OCLs) with hydroxy or methacrylate end groups, is studied by the Langmuir technique in dependence on mean molecular areas and crystallization temperatures. The films on solid substrate as obtained by Langmuir–Schaefer transfer exhibit different lamellar thicknesses, crystal number densities, and lateral sizes. The melting temperature of OCL single crystals at the water and solid surface is proportional to the inverse crystal thickness and generally lower than in bulk PCL. An influence of OCL end groups on the melting behavior is observed mainly at the air–solid interface, where methacrylate end capped OCL melts at lower temperatures than hydroxy end capped OCL. Comparing the underlying substrate, melting/recrystallization of OCL ultrathin films is achievable at lower temperatures at the air–water interface than at the air–solid interface, where recrystallization is not identifiable. Recrystallization at the air–water interface generally occurs at higher temperature than the initial crystallization temperature. The surface pressure, as an additional thermodynamic variable, seems to further affect the crystallization behavior, with crystal thickness and lateral growth rate increasing with surface pressure. The results presented here are important when designing temperature‐sensitive or active nanostructured materials or interfaces based on OCL. %0 journal article %@ 1422-0067 %A Schulz, C., Krüger-Genge, A., Lendlein, A., Küpper, J., Jung, F. %D 2021 %J International Journal of Molecular Sciences %N 3 %P 1493 %R doi:10.3390/ijms22031493 %T Potential Effects of Nonadherent on Adherent Human Umbilical Venous Endothelial Cells in Cell Culture %U https://doi.org/10.3390/ijms22031493 3 %X The adherence and shear-resistance of human umbilical venous endothelial cells (HUVEC) on polymers is determined in vitro in order to qualify cardiovascular implant materials. In these tests, variable fractions of HUVEC do not adhere to the material but remain suspended in the culture medium. Nonadherent HUVEC usually stop growing, rapidly lose their viability and can release mediators able to influence the growth and function of the adherent HUVEC. The aim of this study was the investigation of the time dependent behaviour of HUVEC under controlled nonadherent conditions, in order to gain insights into potential influences of these cells on their surrounding environment in particular adherent HUVEC in the context of in vitro biofunctionality assessment of cardiovascular implant materials. Data from adherent or nonadherent HUVEC growing on polystyrene-based cell adhesive tissue culture plates (TCP) or nonadhesive low attachment plates (LAP) allow to calculate the number of mediators released into the culture medium either from adherent or nonadherent cells. Thus, the source of the inflammatory mediators can be identified. For nonadherent HUVEC, a time-dependent aggregation without further proliferation was observed. The rate of apoptotic/dead HUVEC progressively increased over 90% within two days. Concomitant with distinct blebbing and loss of membrane integrity over time, augmented releases of prostacyclin (PGI2, up to 2.91 ± 0.62 fg/cell) and platelet-derived growth factor BB (PDGF-BB, up to 1.46 ± 0.42 fg/cell) were detected. The study revealed that nonadherent, dying HUVEC released mediators, which can influence the surrounding microenvironment and thereby the results of in vitro biofunctionality assessment of cardiovascular implant materials. Neglecting nonadherent HUVEC bears the risk for under- or overestimation of the materials endothelialization potential, which could lead to the loss of relevant candidates or to uncertainty with regard to their suitability for cardiac applications. One approach to minimize the influence from nonadherent endothelial cells could be their removal shortly after observing initial cell adhesion. However, this would require an individual adaptation of the study design, depending on the properties of the biomaterial used. %0 journal article %@ 0264-1275 %A Sauter, T., Kratz, K., Heuchel, M., Lendlein, A. %D 2021 %J Materials & Design %P 109546 %R doi:10.1016/j.matdes.2021.109546 %T Fiber diameter as design parameter for tailoring the macroscopic shape-memory performance of electrospun meshes %U https://doi.org/10.1016/j.matdes.2021.109546 %X Fibrous shape-memory polymer (SMP) scaffolds were investigated considering the fiber as basic microstructural feature. By reduction of the fiber diameter in randomly oriented electrospun polyetherurethane (PEU) meshes from the micro- to the nano-scale, we observed changes in the molecular orientation within the fibers and its impact on the structural and shape-memory performance. It was assumed that a spatial restriction by reduction of the fiber diameter increases molecular orientation along the orientation of the fiber. The stress-strain relation of random PEU scaffolds is initially determined by the 3D arrangement of the fibers and thus is independent of the molecular orientation. Increasing the molecular orientation with decreasing single fiber diameter in scaffolds composed of randomly arranged fibers did not alter the initial stiffness and peak stress but strongly influenced the elongation at break and the stress increase above the Yield point. Reduction of the single fiber diameter also distinctly improved the shape-memory performance of the scaffolds. Fibers with nanoscale diameters (< 100 nm) possessed an almost complete shape recovery, high recovery stresses and fast relaxation kinetics, while the shape fixity was found to decrease with decreasing fiber diameter. Hence, the fiber diameter is a relevant design parameter for SMP. %0 journal article %@ 1438-7492 %A Sauter, T., Kratz, K., Madbouly, S., Klein, F., Heuchel, M., Lendlein, A. %D 2021 %J Macromolecular Materials and Engineering %N 4 %P 2000730 %R doi:10.1002/mame.202000730 %T Anisotropy Effects in the Shape‐Memory Performance of Polymer Foams %U https://doi.org/10.1002/mame.202000730 4 %X Isotropic and anisotropic shape‐memory polymer foams are prepared by supercritical carbon dioxide foaming from a multiblock copolymer (PDLCL) consisting of poly(ω‐pentadecalactone) and poly(ε‐caprolactone) segments. Analysis by micro‐computed tomography reveals for the anisotropic PDLCL foam cells a high shape anisotropy ratio of R = 1.72 ± 0.62 with a corresponding Young's compression moduli ratio between longitudinal and transversal direction of 4.3. The experimental compression data in the linear elastic range can be well described by the anisotropic open foam model of Gibson and Ashby. A micro‐morphological analysis for single pores using scanning electron microscopy images permits the correlation between the macroscopic stress‐compression behavior and microscale structural changes. %0 conference lecture %@ %A Nie, Y., Wang, W., Xu, X., Ma, N., Lendlein, A. %D 2021 %J 2021 Virtual MRS Spring Meeting %T The response of human induced pluripotent stem cells to cyclic cold shock %U %X %0 conference lecture %@ %A Hoffmann, F., Machatschek, R., Lendlein, A. %D 2021 %J 2021 Virtual MRS Spring Meeting %T Predicting polymer degradation by combining Monte Carlo Simulations and analytical models %U %X %0 conference lecture %@ %A Bastola, A., Behl, M., Soffiatti, P., Rowe, N., Lendlein, A. %D 2021 %J Virtual MRS Spring Meeting 2021 %T Evolutionary Design of Cactus-inspired Soft Robotics Based on 3D-printed Multimaterial Construct %U %X %0 journal article %@ 1422-0067 %A Neffe, A., Löwenberg, C., Julich-Gruner, K., Behl, M., Lendlein, A. %D 2021 %J International Journal of Molecular Sciences %N 11 %P 5892 %R doi:10.3390/ijms22115892 %T Thermally-Induced Shape-Memory Behavior of Degradable Gelatin-Based Networks %U https://doi.org/10.3390/ijms22115892 11 %X Shape-memory hydrogels (SMH) are multifunctional, actively-moving polymers of interest in biomedicine. In loosely crosslinked polymer networks, gelatin chains may form triple helices, which can act as temporary net points in SMH, depending on the presence of salts. Here, we show programming and initiation of the shape-memory effect of such networks based on a thermomechanical process compatible with the physiological environment. The SMH were synthesized by reaction of glycidylmethacrylated gelatin with oligo(ethylene glycol) (OEG) α,ω-dithiols of varying crosslinker length and amount. Triple helicalization of gelatin chains is shown directly by wide-angle X-ray scattering and indirectly via the mechanical behavior at different temperatures. The ability to form triple helices increased with the molar mass of the crosslinker. Hydrogels had storage moduli of 0.27–23 kPa and Young’s moduli of 215–360 kPa at 4 °C. The hydrogels were hydrolytically degradable, with full degradation to water-soluble products within one week at 37 °C and pH = 7.4. A thermally-induced shape-memory effect is demonstrated in bending as well as in compression tests, in which shape recovery with excellent shape-recovery rates Rr close to 100% were observed. In the future, the material presented here could be applied, e.g., as self-anchoring devices mechanically resembling the extracellular matrix. %0 conference lecture %@ %A Moradian, H., Lendlein, A., Gossen, M. %D 2021 %J Virtual MRS Spring Meeting 2021 %T Effect of nucleotide chemistry on expression of in vitro transcribed mRNA %U %X %0 conference lecture %@ %A Moradian, H., Lendlein, A., Gossen, M. %D 2021 %J Virtual MRS Spring Meeting 2021 %T Nucleic acid co-delivery: How to modulate protein co-expression by formulation of payload %U %X %0 journal article %@ 2079-4991 %A Neffe, A., Izraylit, V., Hommes-Schattmann, P., Lendlein, A. %D 2021 %J Nanomaterials %N 6 %P 1472 %R doi:10.3390/nano11061472 %T Soft, Formstable (Co)Polyester Blend Elastomers %U https://doi.org/10.3390/nano11061472 6 %X High crystallization rate and thermomechanical stability make polylactide stereocomplexes effective nanosized physical netpoints. Here, we address the need for soft, form-stable degradable elastomers for medical applications by designing such blends from (co)polyesters, whose mechanical properties are ruled by their nanodimensional architecture and which are applied as single components in implants. By careful controlling of the copolymer composition and sequence structure of poly[(L-lactide)-co-(ε-caprolactone)], it is possible to prepare hyperelastic polymer blends formed through stereocomplexation by adding poly(D-lactide) (PDLA). Low glass transition temperature Tg ≤ 0 °C of the mixed amorphous phase contributes to the low Young’s modulus E. The formation of stereocomplexes is shown in DSC by melting transitions Tm > 190 °C and in WAXS by distinct scattering maxima at 2θ = 12° and 21°. Tensile testing demonstrated that the blends are soft (E = 12–80 MPa) and show an excellent hyperelastic recovery Rrec = 66–85% while having high elongation at break εb up to >1000%. These properties of the blends are attained only when the copolymer has 56–62 wt% lactide content, a weight average molar mass >140 kg·mol−1, and number average lactide sequence length ≥4.8, while the blend is formed with a content of 5–10 wt% of PDLA. The devised strategy to identify a suitable copolymer for stereocomplexation and blend formation is transferable to further polymer systems and will support the development of thermoplastic elastomers suitable for medical applications. %0 journal article %@ 2059-8521 %A Saretia, S., Machatschek, R., Lendlein, A. %D 2021 %J MRS Advances %N 33 %P 790-795 %R doi:10.1557/s43580-021-00067-4 %T Degradation kinetics of oligo(ε-caprolactone) ultrathin films: Influence of crystallinity %U https://doi.org/10.1557/s43580-021-00067-4 33 %X The potential of using crystallinity as morphological parameter to control polyester degradation in acidic environments is explored in ultrathin films by Langmuir technique. Films of hydroxy or methacrylate end-capped oligo(ε-caprolactone) (OCL) are prepared at the air–water interface as a function of mean molecular area (MMA). The obtained amorphous, partially crystalline or highly crystalline ultrathin films of OCL are hydrolytically degraded at pH ~ 1.2 on water surface or on silicon surface as-transferred films. A high crystallinity reduces the hydrolytic degradation rate of the films on both water and solid surfaces. Different acceleration rates of hydrolytic degradation of semi-crystalline films are achieved either by crystals complete melting, partially melting, or by heating them below their melting temperatures. Semi-crystalline OCL films transferred via water onto a solid surface retain their crystalline morphology, degrade in a controlled manner, and are of interest as thermoswitchable coatings for cell substrates and medical devices. %0 conference lecture %@ %A Neffe, A., Zhang, Q., Hommes-Schattmann, P., Wang, W., Xu, X., Ahmad, B., Williams, G., Lendlein, A. %D 2021 %J Virtual MRS Spring Meeting %T Multifunctionality by Core/Shell Design of PLLA/PDLA Nanofibres %U %X %0 conference lecture %@ %A Machatschek, R., Heuchel, M., Lendlein, A. %D 2021 %J Virtual MRS Spring Meeting %T Cross-linking of polyetherimide by bi- and tetrafunctional nucleophiles in ultrathin layers %U %X %0 conference lecture %@ %A Lau, S., Liu, Y., Maier, A., Braune, S., Gossen, M., Lendlein, A. %D 2021 %J Virtual MRS Spring Meeting %T In vitro assessment of polymer thrombogenicity: the effect of endothelial culture conditions on platelet responses %U %X %0 conference lecture %@ %A Bäckemo, J., Liu, Y., Lendlein, A. %D 2021 %J 2021 Virtual MRS Spring Meeting %T Amplification and Modulation of Compliant Mechanisms by Shape Memory Polymers %U %X %0 journal article %@ 2059-8521 %A Neffe, A., Zhang, Q., Hommes-Schattmann, P., Lendlein, A. %D 2021 %J MRS Advances %N 33 %P 786-789 %R doi:10.1557/s43580-021-00058-5 %T Ethylene oxide sterilization of electrospun poly(l-lactide)/poly(d-lactide) core/shell nanofibers %U https://doi.org/10.1557/s43580-021-00058-5 33 %X The application of polymers in medicine requires sterilization while retaining material structure and properties. This demands detailed analysis, which we show exemplarily for the sterilization of PLLA/PDLA core–shell nanofibers with ethylene oxide (EtO). The electrospun patch was exposed to EtO gas (6 vol% in CO2, 1.7 bar) for 3 h at 45 °C and 75% rel. humidity, followed by degassing under pressure/vacuum cycles for 12 h. GC–MS analysis showed that no residual EtO was retained. Fiber diameters (~ 520 ± 130 nm) of the patches remained constant as observed by electron microscopy. Young’s modulus slightly increased and the elongation at break slightly decreased, determined at 37 °C. No changes were detected in 1H-NMR spectra, in molar mass distribution (GPC) or in crystallinity measured for annealed samples with comparable thermal history (Wide Angle X-Ray Scattering). Altogether, EtO emerged as suitable sterilization method for polylactide nanofibers with core–shell morphology. %0 journal article %@ 0264-1275 %A Bastola, A., Rodriguez, N., Behl, M., Soffiatti, P., Rowe, N., Lendlein, A. %D 2021 %J Materials & Design %P 109515 %R doi:10.1016/j.matdes.2021.109515 %T Cactus-inspired design principles for soft robotics based on 3D printed hydrogel-elastomer systems %U https://doi.org/10.1016/j.matdes.2021.109515 %X Plants have evolved many capabilities to anchor, position their stems and leaves favourably, and adapt themselves to different environmental conditions by virtue of growing. Selenicereus setaceus is a cactus and is an impressive example of a climbing plant found mostly in the Atlantic forest formations of southern Brazil. This cactus displays striking changes in stem geometry along different stages of growth: older parts are circular while the younger parts are star-like in shape. Such a transformation in shape optimizes its flexural rigidity and allows the cactus to search in three-dimensionally complex environments. Its organisation offers novel schemes for the design of plant-inspired soft robotic systems. In this paper, we have created multi-material systems for soft robotics that display controlled movements as well as mimicking the cactus stem geometries from star-like to circular. The unique star-shaped geometry is 3D printed using a soft elastomer and hydrogel is used as an actuating component. Through anisotropic swelling, the hydrogel-elastomer system adjusts its configuration and shows a controlled movement. Furthermore, the isotropic swelling of the hydrogel of the artificial cactus multi-material system result in the change in shape from star-like to circular as the cactus does naturally in the tropical forest. %0 journal article %@ 1386-0291 %A Brunacci, N., Wischke, C., Naolou, T., Patzelt, A., Lademann, J., Neffe, A., Lendlein, A. %D 2021 %J Clinical Hemorheology and Microcirculation %N 2 %P 201-219 %R doi:10.3233/CH-200977 %T Formulation of drug-loaded oligodepsipeptide particles with submicron size %U https://doi.org/10.3233/CH-200977 2 %X The size of particulate carriers is key to their transport and distribution in biological systems, and needs to be tailored in the higher submicron range to enable follicular uptake for dermal treatment. Oligodepsipeptides are promising nanoparticulate carrier systems as they can be designed to exhibit enhanced interaction with drug molecules. Here, a fabrication scheme for drug-loaded submicron particles from oligo[3-(S)-sec-butylmorpholine-2,5-dione]diol (OBMD) is presented based on an emulsion solvent evaporation method with cosolvent, surfactant, and polymer concentration as variable process parameters. The particle size (300–950 nm) increased with lower surfactant concentration and higher oligomer concentration. The addition of acetone increased the particle size at low surfactant concentration. Particle size remained stable upon the encapsulation of models compounds dexamethasone (DXM) and Nile red (NR), having different physicochemical properties. DXM was released faster compared to NR due to its higher water solubility. Overall, the results indicated that both drug-loading and size control of OBMD submicron particles can be achieved. When applied on porcine ear skin samples, the NR-loaded particles have been shown to allow NR penetration into the hair follicle and the depth reached with the 300 nm particles was comparable to the one reached with the cream formulation. A potential benefit of the particles compared to a cream is their sustained release profile. %0 conference lecture %@ %A Saretia, S., Machatschek, R., Lendlein, A. %D 2021 %J 2021 Virtual MRS Spring Meeting %T Degradation kinetics of oligo(ε-caprolactone) ultrathin films: Influence of crystallinity %U %X %0 conference lecture %@ %A Tarazona, N., Machatschek, R., Castro-Mayorga, J., Salcedo-Galán, F., Lendlein, A. %D 2021 %J 2021 Virtual MRS Spring Meeting %T Plastics in view of sustainability – an international initiative towards education and training of young scientists %U %X %0 conference lecture (invited) %@ %A Wang, W., Deng, Z., Xu, X., Ma, N., Lendlein, A. %D 2021 %J 2021 Virtual MRS Spring Meeting %T Multifunctional biomaterials for directing and orchestrating behavior and functions of stem cells via mechanical cues %U %X %0 journal article %@ 1386-0291 %A Maring, J., Becker, M., Tung, W., Stamm, C., Ma, N., Lendlein, A. %D 2021 %J Clinical Hemorheology and Microcirculation %N 1 %P 205-216 %R doi:10.3233/CH-219114 %T Cellular response of blood-borne immune cells to PEEU fiber meshes %U https://doi.org/10.3233/CH-219114 1 %X As PEEUm only elicits a minimal response from naïve monocytes but not from monocytes, peripheral blood mononuclear cells (PBMCs) or T cells, the slight improvement in response to PEEUm + E might not justify the additional effort of coating with a human ECM. %0 conference poster %@ %A Nie, Y., Xu, X., Wang, W., Ma, N., Lendlein, A. %D 2021 %J Advanced Functional Polymers for Medicine (AFPM) %T Freestanding biohybrid systems made of polydopamine film and human keratinocytes %U %X %0 journal article %@ 2159-6859 %A Izraylit, V., Liu, Y., Tarazona, N., Machatschek, R., Lendlein, A. %D 2021 %J MRS Communications %N 6 %P 850-855 %R doi:10.1557/s43579-021-00107-y %T Crystallization and degradation behaviour of multiblock copolyester blends in Langmuir monolayers %U https://doi.org/10.1557/s43579-021-00107-y 6 %X Supporting the wound healing of soft tissues requires fixation devices becoming more elastic while degrading. To address this unmet need, we designed a blend of degradable multiblock copolymers, which is cross-linked by PLA stereocomplexation combining two soft segments differing substantially in their hydrolytic degradation rate. The degradation path and concomitant structural changes are predicted by Langmuir monolayer technique. The fast hydrolysis of one soft segment leads to a decrease of the total polymer mass at constant physical cross-linking density. The corresponding increase of the average spacing between the network nodes suggests the targeted increase of the blend’s flexibility. %0 conference lecture (invited) %@ %A Behl, M., Lendlein, A. %D 2021 %J Living Machines 2021; The International Conference on Biomimentic and Biohybrid Systems %T Bio-inspired polymer-based actuators for soft robots %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2021 %J The ICRS-PAT 2021 Joint Workshop (Controlled Release Society (CRS) & Polymers for Advanced Technologies Society (PAT)) %T Polymer-based soft actuators for robotics and medicine %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2021 %J 59th Tutzing Symposium 2021 Polymers for a better life and circular economy %T Predicting polymer degradation: current methods and challenges %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2021 %J Berufsorientierung Vicco-von-Bülow-Gymnasium Stahnsdorf 2021 %T Kunststoffe sind mehr als nur Mikroplastik – Verwendung in der Medizin; Berufe in der Biomaterialforschung %U %X %0 journal article %@ 1744-683X %A Friess, F., Lendlein, A., Wischke, C. %D 2021 %J Soft Matter %N 41 %P 9326-9331 %R doi:10.1039/d1sm00947h %T Switching microobjects from low to high aspect ratios using a shape-memory effect %U https://doi.org/10.1039/d1sm00947h 41 %X Spherical particles from shape-memory polymers (SMP) can be stretched to ellipsoids with high aspect ratio (AR) and temporarily stabilized. They can switch back to low AR upon thermal stimulation. Here, the creation of an alternative shape-switching capability of particles from low to high AR is introduced, where a SMP matrix from polyvinyl alcohol (PVA) is used to create crosslinked high AR particles and to program the embedded micrometer-sized particles from a second SMP (oligo(ε-caprolactone) micronetworks, MN) with a low switching temperature Tsw. This programming proceeds through shape-recovery of the PVA matrix, from which the MN are harvested by PVA matrix dissolution. The use of a dissolvable SMP matrix may be a general strategy to efficiently create systems with complex moving capabilities. %0 conference lecture %@ %A Lendlein, A., Schroeter, M. %D 2021 %J Girls & Boys Day 2021 %T Forschung bei Hereon - Polymere in der Medizin %U %X %0 conference poster %@ %A Machatschek, R., Saretia, S., Lendlein, A. %D 2021 %J MRS Fall Meeting 2021 %T Degradation of 2D Materials Formed by Crosslinking of Hydrophilic Macromolecules %U %X %0 conference poster %@ %A Nie, Y., Xu, X., Wang, W., Bellomo, B., Ma, N., Lendlein, A. %D 2021 %J MRS Fall Meeting 2021 %T The anti-aging effects of polydopamine particles in human skin epithelial keratinocytes %U %X %0 journal article %@ 2373-9878 %A Krüger-Genge, A., Hauser, S., Neffe, A., Liu, Y., Lendlein, A., Pietzsch, J., Jung, F. %D 2021 %J ACS Biomaterials Science & Engineering %N 2 %P 527-540 %R doi:10.1021/acsbiomaterials.0c01432 %T Response of Endothelial Cells to Gelatin-Based Hydrogels %U https://doi.org/10.1021/acsbiomaterials.0c01432 2 %X The establishment of confluent endothelial cell (EC) monolayers on implanted materials has been identified as a concept to avoid thrombus formation but is a continuous challenge in cardiovascular device engineering. Here, material properties of gelatin-based hydrogels obtained by reacting gelatin with varying amounts of lysine diisocyanate ethyl ester were correlated with the functional state of hydrogel contacting venous EC (HUVEC) and HUVEC’s ability to form a monolayer on these hydrogels. The density of adherent HUVEC on the softest hydrogel at 37 °C (G’ = 1.02 kPa, E = 1.1 ± 0.3 kPa) was significantly lower (125 mm–1) than on the stiffer hydrogels (920 mm–1; G’ = 2.515 and 5.02 kPa, E = 4.8 ± 0.8 and 10.3 ± 1.2 kPa). This was accompanied by increased matrix metalloprotease activity (9 pmol·min–2 compared to 0.6 pmol·min–2) and stress fiber formation, while cell-to-cell contacts were comparable. Likewise, release of eicosanoids (e.g., prostacyclin release of 1.7 vs 0.2 pg·mL–1·cell–1) and the pro-inflammatory cytokine MCP-1 (8 vs <1.5 pg·mL–1·cell–1) was higher on the softer than on the stiffer hydrogels. The expressions of pro-inflammatory markers COX-2, COX-1, and RAGE were slightly increased on all hydrogels on day 2 (up to 200% of the control), indicating a weak inflammation; however, the levels dropped to below the control from day 6. The study revealed that hydrogels with higher moduli approached the status of a functionally confluent HUVEC monolayer. The results indicate the promising potential especially of the discussed gelatin-based hydrogels with higher G’ as biomaterials for implants foreseen for the venous system. %0 journal article %@ 1386-0291 %A Krüger-Genge, A., Tondera, C., Hauser, S., Braune, S., Görs, J., Roch, T., Klopfleisch, R., Neffe, A., Lendlein, A., Pietzsch, J., Jung, F. %D 2021 %J Clinical Hemorheology and Microcirculation %N 3 %P 335-350 %R doi:10.3233/CH-201028 %T Immunocompatibility and non-thrombogenicity of gelatin-based hydrogels %U https://doi.org/10.3233/CH-201028 3 %X Immunocompatibility and non-thrombogenicity are important requirements for biomedical applications such as vascular grafts. Here, gelatin-based hydrogels formed by reaction of porcine gelatin with increasing amounts of lysine diisocyanate ethyl ester were investigated in vitro in this regard. In addition, potential adverse effects of the hydrogels were determined using the “Hen’s egg test on chorioallantoic membrane” (HET-CAM) test and a mouse model. The study revealed that the hydrogels were immunocompatible, since complement activation was absent and a substantial induction of reactive oxygen species generating monocytes and neutrophils could not be observed in whole human blood. The density as well as the activation state of adherent thrombocytes was comparable to medical grade polydimethylsiloxane, which was used as reference material. The HET-CAM test confirmed the compatibility of the hydrogels with vessel functionality since no bleedings, thrombotic events, or vessel destructions were observed. Only for the samples synthesized with the highest LDI amount the number of growing blood vessels in the CAM was comparable to controls and significantly higher than for the softer materials. Implantation into mice showed the absence of adverse or toxic effects in spleen, liver, or kidney, and only a mild lymphocytic activation in the form of a follicular hyperplasia in draining lymph nodes (slightly increased after the implantation of the material prepared with the lowest LDI content). These results imply that candidate materials prepared with mid to high amounts of LDI are suitable for the coating of the blood contacting surface of cardiovascular implants. %0 journal article %@ 1422-0067 %A Lau, S., Gossen, M., Lendlein, A. %D 2021 %J International Journal of Molecular Sciences %N 23 %P 13120 %R doi:10.3390/ijms222313120 %T Designing Cardiovascular Implants Taking in View the Endothelial Basement Membrane %U https://doi.org/10.3390/ijms222313120 23 %X Insufficient endothelialization of cardiovascular grafts is a major hurdle in vascular surgery and regenerative medicine, bearing a risk for early graft thrombosis. Neither of the numerous strategies pursued to solve these problems were conclusive. Endothelialization is regulated by the endothelial basement membrane (EBM), a highly specialized part of the vascular extracellular matrix. Thus, a detailed understanding of the structure–function interrelations of the EBM components is fundamental for designing biomimetic materials aiming to mimic EBM functions. In this review, a detailed description of the structure and functions of the EBM are provided, including the luminal and abluminal interactions with adjacent cell types, such as vascular smooth muscle cells. Moreover, in vivo as well as in vitro strategies to build or renew EBM are summarized and critically discussed. The spectrum of methods includes vessel decellularization and implant biofunctionalization strategies as well as tissue engineering-based approaches and bioprinting. Finally, the limitations of these methods are highlighted, and future directions are suggested to help improve future design strategies for EBM-inspired materials in the cardiovascular field. %0 journal article %@ 2059-8521 %A Saretia, S., Machatschek, R., Lendlein, A. %D 2021 %J MRS Advances %N 10 %P 283-290 %R doi:10.1557/s43580-021-00020-5 %T Highly crystalline PCL ultrathin films as thermally switchable biomaterial coatings %U https://doi.org/10.1557/s43580-021-00020-5 10 %X Semi-crystalline oligomers are explored as functionalized thermoswitchable coatings for modification of biomaterials surface. Highly crystalline oligo(ε-caprolactone) (OCL) films are prepared at the air–water interface by the Langmuir technique, which consist of tightly packed single crystals. Their morphology and melting temperature can be tuned by the chemical structure of the OCL end-groups (hydroxy or methacrylate) and by the crystallization temperature (12 or 21 °C) as physical parameter. This demand of high crystallite density and adjustable morphology of coatings is not met by conventional methodologies for preparing thin films, e.g., spin coating, spray coating, or solvent evaporation. The high crystallinity reduces the enzymatic degradation rate of the films on both water and solid surfaces. The high density of methacrylate end-groups at the crystal surfaces enables post-functionalization, which was demonstrated using fluorescein dimethacrylate as chemically linked label. The thermoswitching behavior (melting and recrystallization) of fluorescein functionalized, highly crystalline OCL films shows temperature-dependent distribution of the chemically linked fluorescein moieties, which are accumulated on the surfaces of crystals, and homogeneously dispersed when the crystals are molten. Thermally switchable highly crystalline films are relevant for cell substrates modulating adhesion at the biointerface or for coatings as barrier layer influencing the degradation rate. %0 conference poster %@ %A Sahabudeen, H., Machatschek, R., Liu, Y., Lendlein, A. %D 2021 %J Advanced Functional Polymers for Medicine (AFPM) %T Non-destructive mechanical testing of freestanding 2D MOF by interfacial rheology %U %X %0 journal article %@ 2059-8521 %A Neffe, A., Löwenberg, C., Lendlein, A. %D 2021 %J MRS Advances %N 33 %P 796-800 %R doi:10.1557/s43580-021-00136-8 %T Hydrogel networks by aliphatic dithiol Michael addition to glycidylmethacrylated gelatin %U https://doi.org/10.1557/s43580-021-00136-8 33 %X Functionalization of gelatin with glycidylmethacrylate (GMA-gelatin) enables network formation employing the double bond, so that the reaction is orthogonal to the inherent functional groups in the biomacromolecule. Here, network formation by crosslinking of GMA-gelatin with hexane 1,6-dithiol or nonane 1,9-dithiol to tailor properties and enable a shape-memory effect is shown by 1H NMR and FT-IR spectroscopy. Hydrogel swelling (460–1900 vol%) and mechanical properties (Young’s modulus E = 59–512 kPa, elongation at break εb = 44–127%) depended on the molecular composition of the networks and temperature. Increased crosslinker length, thiol:methacrylate molar ratio, and precursor concentrations led to denser networks. Change of properties with temperature suggested adoption of triple helices by gelatin chains, forming physical netpoints at lower temperatures (< 20 °C). However, the limited freedom of the gelatin chains to move allowed only a minimal extent of triple helices formation, as it became apparent from the related signal in wide-angle X-ray scattering and the thermal transition associated to triple helices in some networks by DSC. The presented strategy is likely transferable to other biomacromolecules, and the results suggest that too short crosslinkers may result in a significant amount of grafting rather than network formation. %0 journal article %@ 2374-7951 %A Lendlein, A., Heuchel, M. %D 2021 %J ACS Central Science %N 10 %P 1599-1601 %R doi:10.1021/acscentsci.1c01032 %T Shape-Memory Polymers Designed in View of Thermomechanical Energy Storage and Conversion Systems %U https://doi.org/10.1021/acscentsci.1c01032 10 %X one-way shape-memory polymers. %0 journal article %@ 1944-8244 %A Balk, M., Behl, M., Nöchel, U., Lendlein, A. %D 2021 %J ACS Applied Materials and Interfaces %N 7 %P 8095-8101 %R doi:10.1021/acsami.1c00466 %T Enzymatically Triggered Jack-in-the-Box-like Hydrogels %U https://doi.org/10.1021/acsami.1c00466 7 %X Enzymes can support the synthesis or degradation of biomacromolecules in natural processes. Here, we demonstrate that enzymes can induce a macroscopic-directed movement of microstructured hydrogels following a mechanism that we call a “Jack-in-the-box” effect. The material’s design is based on the formation of internal stresses induced by a deformation load on an architectured microscale, which are kinetically frozen by the generation of polyester locking domains, similar to a Jack-in-the-box toy (i.e., a compressed spring stabilized by a closed box lid). To induce the controlled macroscopic movement, the locking domains are equipped with enzyme-specific cleavable bonds (i.e., a box with a lock and key system). As a result of enzymatic reaction, a transformed shape is achieved by the release of internal stresses. There is an increase in entropy in combination with a swelling-supported stretching of polymer chains within the microarchitectured hydrogel (i.e., the encased clown pops-up with a pre-stressed movement when the box is unlocked). This utilization of an enzyme as a physiological stimulus may offer new approaches to create interactive and enzyme-specific materials for different applications such as an optical indicator of the enzyme’s presence or actuators and sensors in biotechnology and in fermentation processes. %0 conference lecture %@ %A Gossen, M., Lau, S., Moradian, H., Behl, M., Lendlein, A. %D 2021 %J 2nd Joint Meeting of The European Society for Clinical Hemorheology and Microcirculation; The International Society for Clinical Hemorheology; and The International Society of Biorheology (ESCHM-ISCHM-ISB) %T Nanoparticle-mediated delivery of nucleic acids in primary human endothelial cells %U %X %0 conference poster %@ %A Folikumah, M., Behl, M., Lendlein, A. %D 2021 %J Advanced Functional Polymers for Medicine (AFPM) %T Design and synthesis of 3-arm MMP-sensitive thio-depsipeptide hydrogel precursor %U %X %0 conference poster %@ %A Nie, Y., Wang, W., Xu, X., Ma, N., Lendlein, A. %D 2021 %J 2nd Joint Meeting of The European Society for Clinical Hemorheology and Microcirculation; The International Society for Clinical Hemorheology; and The International Society of Biorheology (ESCHM-ISCHM-ISB) %T Stiffening of human keratinocytes in response to cyclic temperature changes %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2021 %J Advanced Functional POlymers for Medicine (AFPM) %T Stimuli-Responsiveness in Hydrogels by Translating Processes from the Molecular Level via Porous Microstructures to the Macroscopic Scale %U %X %0 conference lecture (invited) %@ %A Heuchel, M., Lendlein, A. %D 2021 %J XXIX International Materials Research Congress (IMRC) %T Design Criteria and Fabrication Schemes for Fiber-Based Actuators %U %X %0 conference poster %@ %A Tung, W., Wang, W., Ma, N., Lendlein, A. %D 2021 %J Advanced Functional Polymers for Medicine (AFPM) %T Macrophage driven degradation of electrospun PEEU fibers %U %X %0 journal article %@ 2059-8521 %A Tung, W., Sun, X., Wang, W., Xu, X., Ma, N., Lendlein, A. %D 2021 %J MRS Advances %N 10 %P 276-282 %R doi:10.1557/s43580-020-00001-0 %T Structure, mechanical properties and degradation behavior of electrospun PEEU fiber meshes and films %U https://doi.org/10.1557/s43580-020-00001-0 10 %X The capability of a degradable implant to provide mechanical support depends on its degradation behavior. Hydrolytic degradation was studied for a polyesteretherurethane (PEEU70), which consists of poly(p-dioxanone) (PPDO) and poly(ε-caprolactone) (PCL) segments with a weight ratio of 70:30 linked by diurethane junction units. PEEU70 samples prepared in the form of meshes with average fiber diameters of 1.5 µm (mesh1.5) and 1.2 µm (mesh1.2), and films were sterilized and incubated in PBS at 37 °C with 5 vol% CO2 supply for 1 to 6 weeks. Degradation features, such as cracks or wrinkles, became apparent from week 4 for all samples. Mass loss was found to be 11 wt%, 6 wt%, and 4 wt% for mesh1.2, mesh1.5, and films at week 6. The elongation at break decreased to under 20% in two weeks for mesh1.2. In case of the other two samples, this level of degradation was achieved after 4 weeks. The weight average molecular weight of both PEEU70 mesh and film samples decreased to below 30 kg/mol when elongation at break dropped below 20%. The time period of sustained mechanical stability of PEEU70-based meshes depends on the fiber diameter and molecular weight. %0 journal article %@ 0266-3538 %A Wong, T., Behl, M., Yusoff, N., Li, T., Wahit, M., Ismail, A., Zhao, Q., Lendlein, A. %D 2020 %J Composites Science and Technology %P 108138 %R doi:10.1016/j.compscitech.2020.108138 %T Bio-based composites from plant based precursors and hydroxyapatite with shape-memory capability %U https://doi.org/10.1016/j.compscitech.2020.108138 %X A series of bio-based composites consisting of degradable thermoset poly[xylitol-(1,12-dodecanedioate)] (PXD) and hydroxyapatite microparticles (HA) was prepared. Equimolar amounts of xylitol and 1,12-dodecanedioic acid were reacted under catalyst-free polyesterification and the synthesized composites (PXDHCy) consist HA particles ranging between 0 wt% and 20 wt%. Crystallinity of the polymer matrix decreased at low content of HA (5 wt%) as the microparticles hindered crystallization of 1,12-dodecanedioate segment and then increased when the content of HA was raised (from 10 wt% to 20 wt%) as the polymer chains crystallized on surface of microparticles. All PXD and PXDHCy are able to hydrolytically degrade with around 7 wt% to 20 wt% mass loss after 16 weeks incubation in water (rate depends on HA content). The capability of PXD and PXDHCy composites to keep a temporary shape after a deformation process correlated with the polymer crystallinity whereas the shape recovery was 99%. The switching temperatures of PXD and PXDHCy composites ranged around 50 °C (and correlated to the melting-transition temperature) and did not vary with the loading of HA. A prototype of PXDHCy composite smart fixation plug was demonstrated and showed excellent potential to be used as bio-based fixation device for household appliances. %0 conference lecture %@ %A Nie, Y., Xu, X., Wang, W., Ma, N., Lendlein, A. %D 2020 %J 39. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheoligie (DGKMH) %T Spheroid formation of human keratinocyte: balancing between cell-substrate and cell-cell interaction %U %X %0 conference lecture %@ %A Nie, Y., Xu, X., Wang, W., Ma, N., Lendlein, A. %D 2020 %J 39. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheoligie (DGKMH) %T The effects of oscillatory temperature on HaCaT keratinocytes behaviors %U %X %0 journal article %@ 1525-7797 %A Löwenberg, C., Julich-Gruner, K., Neffe, A., Behl, M., Lendlein, A. %D 2020 %J Biomacromolecules %N 6 %P 2024-2031 %R doi:10.1021/acs.biomac.9b01753 %T Salt-Induced Shape-Memory Effect in Gelatin-Based Hydrogels %U https://doi.org/10.1021/acs.biomac.9b01753 6 %X Hydrophilic biopolymers display a strong tendency for self-organization into stable secondary, tertiary, and quaternary structures in aqueous environments. These structures are sensitive to changes in external conditions, such as temperature, pH or ions/salts, which may lead to molecular and/or macroscopic transitions. Here, we report on biopolymer-based stimuli-sensitive switchable matrices showing a shape-memory function as an output being alternatively switched by two different input signals, such as environmental changes in salt concentration or temperature. This was realized by implementing a shape-memory function in hydrogels based on the coil-to-helix transition of protein chains in gelatin-based networks. The hydrogels exhibited mechanical properties similar to that of soft tissue (storage modulus G′ = 1–100 kPa) and high swelling capabilities (Q = 1000–3000 vol %). In these gelatin-based networks, the covalent netpoints defined the permanent shape while after deformation helicalization of the gelatin acted as reversible stimuli-sensitive switches providing additional crosslinks capable of fixing the deformed temporary shape. By using either chaotropic salts to suppress gelatin helicalization or kosmotropic salts to support conformational changes of gelatin toward a helical orientation, these additional crosslinks could be cleaved or formed. In bending experiments, the strain fixity (Rf) and strain recovery ratios (Rr) were determined. While Rf ranged from 65 to 95% and was depending on the network composition, Rr were independent of the hydrogel composition with values about 100%. In addition, Rf and Rr were independent of the type of chaotropic salt that was used in this study, showing equal Rf and Rr values for MgCl2, NaSCN, and Mg(SCN)2. %0 journal article %@ 1386-0291 %A Nie, Y., Xu, X., Wang, W., Ma, N., Lendlein, A. %D 2020 %J Clinical Hemorheology and Microcirculation %N 2 %P 317-327 %R doi:10.3233/CH-209208 %T The effects of oscillatory temperature on HaCaT keratinocyte behaviors %U https://doi.org/10.3233/CH-209208 2 %X ΔT conditions resulted in the re-arrangement of the cytoskeleton in HaCaT cells, which showed similarity to the temperature-induced disassemble and re-assemble of cytoskeletons in keratinocyte in vivo. The altered cytoskeleton arrangement resulted in the cell enlargement and stiffening, which reflected the changes in cellular functions. The application of oscillatory temperature in the in vitro culture of keratinocytes provides a way to gain more insights into the role of skin in response to environmental stimuli and maintaining its homeostasis in vivo. %0 journal article %@ 0014-3057 %A Izraylit, V., Hommes-Schattmann, P., Neffe, A., Gould, O., Lendlein, A. %D 2020 %J European Polymer Journal %P 109908 %R doi:10.1016/j.eurpolymj.2020.109908 %T Alkynyl-functionalized chain-extended PCL for coupling to biological molecules %U https://doi.org/10.1016/j.eurpolymj.2020.109908 %X Chemical functionalization of poly(ε-caprolactone) (PCL) enables a molecular integration of additional function. Here, we report an approach to incorporate reactive alkynyl side-groups by synthesizing a chain-extended PCL, where the reactive site is introduced through the covalently functionalizable chain extender 3-(prop-2-yn-1-yloxy)propane-1,2-diol (YPD). Chain-extended PCL with Mw of 101 to 385 kg·mol−1 were successfully synthesized in a one-pot reaction from PCL-diols with various molar masses, L-lysine ethyl ester diisocyanate (LDI) or trimethyl(hexamethylene)diisocyanate (TMDI), and YPD, in which the density of functionalizable groups and spacing between them can be controlled by the composition of the polymer. The employed diisocyanate compounds and YPD possess an asymmetric structure and form a non-crystallizable segment leaving the PCL crystallites to dominate the material’s mechanical properties. The mixed glass transition temperature Tg = −60 to −46 °C of the PCL/polyurethane amorphous phase maintains the synthesized materials in a highly elastic state at ambient and physiological conditions. Reaction conditions for covalent attachment in copper(I)-catalyzed azide-alkyne-cycloaddition reactions (CuAAC) in solution were optimized in a series of model reactions between the alkyne moieties of the chain-extended PCL and benzyl azide, reaching conversions over 95% of the alkyne moieties and with yields of up to 94% for the purified functionalized PCL. This methodology was applied for reaction with the azide-functionalized cell adhesion peptide GRGDS. The required modification of the peptide provides selectivity in the coupling reactions. The obtained results suggest that YPD could potentially be employed as versatile molecular unit for the creation of a variety of functionalizable polyesters as well as polyurethanes and polycarbonates offering efficient and selective click-reactions. %0 journal article %@ 1438-7492 %A Liu, Y., Gould, O., Rudolph, T., Fang, L., Kratz, K., Lendlein, A. %D 2020 %J Macromolecular Materials and Engineering %N 10 %P 2000333 %R doi:10.1002/mame.202000333 %T Polymeric Microcuboids Programmable for Temperature‐Memory %U https://doi.org/10.1002/mame.202000333 10 %X Microobjects with programmable mechanical functionality are highly desirable for the creation of flexible electronics, sensors, and microfluidic systems, where fabrication/programming and quantification methods are required to fully control and implement dynamic physical behavior. Here, programmable microcuboids with defined geometries are prepared by a template‐based method from crosslinked poly[ethylene‐co‐(vinyl acetate)] elastomers. These microobjects could be programmed to exhibit a temperature‐memory effect or a shape‐memory polymer actuation capability. Switching temperatures Tsw during shape recovery of 55 ± 2, 68 ± 2, 80 ± 2, and 86 ± 2 °C are achieved by tuning programming temperatures to 55, 70, 85, and 100 °C, respectively. Actuation is achieved with a reversible strain of 2.9 ± 0.2% to 6.7 ± 0.1%, whereby greater compression ratios and higher separation temperatures induce a more pronounced actuation. Micro‐geometry change is quantified using optical microscopy and atomic force microscopy. The realization and quantification of microparticles, capable of a tunable temperature responsive shape‐change or reversible actuation, represent a key development in the creation of soft microscale devices for drug delivery or microrobotics. %0 journal article %@ 0946-2716 %A Moradian, H., Lendlein, A., Gossen, M. %D 2020 %J Journal of Molecular Medicine %P 1767-1779 %R doi:10.1007/s00109-020-01956-1 %T Strategies for simultaneous and successive delivery of RNA %U https://doi.org/10.1007/s00109-020-01956-1 %X Advanced non-viral gene delivery experiments often require co-delivery of multiple nucleic acids. Therefore, the availability of reliable and robust co-transfection methods and defined selection criteria for their use in, e.g., expression of multimeric proteins or mixed RNA/DNA delivery is of utmost importance. Here, we investigated different co- and successive transfection approaches, with particular focus on in vitro transcribed messenger RNA (IVT-mRNA). Expression levels and patterns of two fluorescent protein reporters were determined, using different IVT-mRNA doses, carriers, and cell types. Quantitative parameters determining the efficiency of co-delivery were analyzed for IVT-mRNAs premixed before nanocarrier formation (integrated co-transfection) and when simultaneously transfecting cells with separately formed nanocarriers (parallel co-transfection), which resulted in a much higher level of expression heterogeneity for the two reporters. Successive delivery of mRNA revealed a lower transfection efficiency in the second transfection round. All these differences proved to be more pronounced for low mRNA doses. Concurrent delivery of siRNA with mRNA also indicated the highest co-transfection efficiency for integrated method. However, the maximum efficacy was shown for successive delivery, due to the kinetically different peak output for the two discretely operating entities. Our findings provide guidance for selection of the co-delivery method best suited to accommodate experimental requirements, highlighting in particular the nucleic acid dose-response dependence on co-delivery on the single-cell level. %0 conference poster %@ %A Machatschek, R., Lendlein, A. %D 2020 %J Controlled Release Society - CRS 2020 Virtual Annual Meeting %T Monolayer studies as tool to predict the degradation behavior of (co)polyester matrices %U %X %0 conference lecture %@ %A Lendlein, A., Tarazona, N., Machatschek, R. %D 2020 %J Controlled Release Society - CRS 2020 Virtual Annual Meeting %T Influence of enzymes on the degradation behavior of polyhydroxyalkanoates determined in Langmuir degradation studies %U %X %0 conference poster %@ %A Liu, Y., Gould, O., Kratz, K., Lendlein, A. %D 2020 %J Virtual MRS Spring/Fall Meeting 2020 %T Reversible Shape-Memory Actuation of Individual Micro-/Nanofibers %U %X %0 conference lecture %@ %A Behl, M., Zhao, Q., Lendlein, A. %D 2020 %J Virtual MRS Spring/Fall Meeting 2020 %T Glucose-responsive shape-memory cryogels %U %X %0 journal article %@ 2196-7350 %A Tarazona, N., Machatschek, R., Lendlein, A. %D 2020 %J Advanced Materials Interfaces %N 17 %P 2000872 %R doi:10.1002/admi.202000872 %T Influence of Depolymerases and Lipases on the Degradation of Polyhydroxyalkanoates Determined in Langmuir Degradation Studies %U https://doi.org/10.1002/admi.202000872 17 %X Microbially produced polyhydroxyalkanoates (PHAs) are polyesters that are degradable by naturally occurring enzymes. Albeit PHAs degrade slowly when implanted in animal models, their disintegration is faster compared to abiotic hydrolysis under simulated physiological environments. Ultrathin Langmuir‐Blodgett (LB) films are used as models for fast in vitro degradation testing, to predict enzymatically catalyzed hydrolysis of PHAs in vivo. The activity of mammalian enzymes secreted by pancreas and liver, potentially involved in biomaterials degradation, along with microbial hydrolases is tested toward LB‐films of two model PHAs, poly(3‐R‐hydroxybutyrate) (PHB) and poly[(3‐R‐hydroxyoctanoate)‐co‐(3‐R‐hydroxyhexanoate)] (PHOHHx). A specific PHA depolymerase from Streptomyces exfoliatus, used as a positive control, is shown to hydrolyze LB‐films of both polymers regardless of their side‐chain‐length and phase morphology. From amorphous PHB and PHOHHx, ≈80% is eroded in few hours, while mass loss for semicrystalline PHB is 25%. Surface potential and interfacial rheology measurements show that material dissolution is consistent with a random‐chain‐scission mechanism. Degradation‐induced crystallization of semicrystalline PHB LB‐films is also observed. Meanwhile, the surface and the mechanical properties of both LB‐films remain intact throughout the experiments with lipases and other microbial hydrolases, suggesting that non‐enzymatic hydrolysis could be the predominant factor for acceleration of PHAs degradation in vivo. %0 conference poster %@ %A Hoffmann, F., Machatschek, R., Barbirz, S., Lendlein, A. %D 2020 %J Virtual MRS Spring/Fall Meeting %T Molecular modeling of biomaterial degradation in two dimensions %U %X %0 online contribution %@ %A Benner, S., Lendlein, A. %D 2020 %J Faszination Chemie - Die Informationsplattform der GDCh %T Formgedächtnispolymere - von Wärmeschrumpfartikeln zu künstlichen Muskeln %U %X %0 conference poster %@ %A Saretia, S., Machatschek, R., Lendlein, A. %D 2020 %J 2020 Virtual MRS Spring/Fall Meeting %T Highly crystalline PCL ultrathin films as thermally switchable biomaterial coatings %U %X %0 journal article %@ 1386-0291 %A Haase, T., Klopfleisch, R., Krost, A., Sauter, T., Kratz, K., Peter, J., Jung, F., Lendlein, A., Zohlnhöfer, D., Rüder, C. %D 2020 %J Clinical Hemorheology and Microcirculation %N 2 %P 163-176 %R doi:10.3233/CH-190748 %T In vivo biocompatibility study of degradable homo- versus multiblock copolymers and their (micro)structure compared to an established biomaterial %U https://doi.org/10.3233/CH-190748 2 %X Copolyetheresterurethane (PDC) is a biodegradable, shape-memory biomaterial, which has been shown to be of low toxicity and pro-angiogenic in vitro. In the present study we examined the in vivo compatibility of PDC as a compression molded film and as electrospun scaffolds and its well established constituent, the homopolymer poly(p-dioxanone) (PPDO), which were compared with the clinically used poly[(vinylidene fluoride)-co-hexafluoropropene] (PVDF) as reference material. The materials were implanted in the subcutaneous tissue of mice and the host responses were analyzed histologically 7 and 28 days after implantation. All materials induced a foreign body response (FRB) including the induction of foreign body giant cells and a peripheral fibrous capsule. PDC, PPDO and PVDF films showed no signs of degradation after 28 days. PDC films showed a significantly reduced associated macrophage layer and fibrous capsule on their surface. Few fragments of PDC and PPDO scaffolds were present at the implantation site, while PVDF scaffolds were still present in large amounts at day 28. Especially aligned electrospun PDC scaffold induced a significantly thinner fibrous and a slightly reduced inflammatory response after 28 days of implantation. In addition, only PDC aligned fibrous scaffold structures induced a significant increase in angiogenesis. In summary, PDC films outperformed PPDO and PVDF films in terms of compatibility, especially in capsule and macrophage layer thickness. Through microstructuring of PDC and PPDO into scaffolds an almost complete degradation was observed after 28 days, while their respective films remained almost unchanged. However, the capsule thickness of all scaffolds was comparable to the films after 28 days. Finally, the parallel arrangement of PDC fibers enabled a strong enhancement of angiogenesis within the scaffold. Hence, material chemistries influence overall compatibility in vivo, while angiogenesis could be influenced more strongly by microstructural parameters than chemical ones. %0 journal article %@ 2059-8521 %A Deng, Z., Wang, W., Xu, X., Ma, N., Lendlein, A. %D 2020 %J MRS Advances %N 46 - 47 %P 2381-2390 %R doi:10.1557/adv.2020.235 %T Modulation of Mesenchymal Stem Cell Migration using Programmable Polymer Sheet Actuators %U https://doi.org/10.1557/adv.2020.235 46 - 47 %X Recruitment of mesenchymal stem cells (MSCs) to damaged tissue is a crucial step to modulate tissue regeneration. Here, the migration of human adipose-derived stem cells (hADSCs) responding to thermal and mechanical stimuli was investigated using programmable shape-memory polymer actuator (SMPA) sheets. Changing the temperature repetitively between 10 and 37 °C, the SMPA sheets are capable of reversibly changing between two different pre-defined shapes like an artificial muscle. Compared to non-actuating sheets, the cells cultured on the programmed actuating sheets presented a higher migration velocity (0.32 ± 0.1 vs. 0.57 ± 0.2 μm/min). These results could motivate the next scientific steps, for example, to investigate the MSCs pre-loaded in organoids towards their migration potential. %0 journal article %@ 2059-8521 %A Hoffmann, F., Machatschek, R., Lendlein, A. %D 2020 %J MRS Advances %N 52 - 53 %P 2737-2749 %R doi:10.1557/adv.2020.386 %T Understanding the impact of crystal lamellae organization on small molecule diffusion using a Monte Carlo approach %U https://doi.org/10.1557/adv.2020.386 52 - 53 %X Many physicochemical processes depend on the diffusion of small molecules through solid materials. While crystallinity in polymers is advantageous with respect to structure performance, diffusion in such materials is difficult to predict. Here, we investigate the impact of crystal morphology and organization on the diffusion of small molecules using a lattice Monte Carlo approach. Interestingly, diffusion determined with this model does not depend on the internal morphology of the semi-crystalline regions. The obtained insight is highly valuable for developing predictive models for all processes in semi-crystalline polymers involving mass transport, like polymer degradation or drug release, and provide design criteria for the time-dependent functional behavior of multifunctional polymer systems. %0 journal article %@ 0884-2914 %A Behl, M., Zhao, Q., Lendlein, A. %D 2020 %J Journal of Materials Research %N 18 %P 2396-2404 %R doi:10.1557/jmr.2020.204 %T Glucose-responsive shape-memory cryogels %U https://doi.org/10.1557/jmr.2020.204 18 %X Boronic ester bonds can be reversibly formed between phenylboronic acid (PBA) and triol moieties. Here, we aim at a glucose-induced shape-memory effect by implementing such bonds as temporary netpoints, which are cleavable by glucose and by minimizing the volume change upon stimulation by a porous cryogel structure. The polymer system consisted of a semi-interpenetrating network (semi-IPN) architecture, in which the triol moieties were part of the permanent network and the PBA moieties were located in the linear polymer diffused into the semi-IPN. In an alkaline medium (pH = 10), the swelling ratio was approximately 35, independent of Cglu varied between 0 and 300 mg/dL. In bending experiments, shape fixity Rf ≈ 80% and shape recovery Rr ≈ 100% from five programming/recovery cycles could be determined. Rr was a function of Cglu in the range from 0 to 300 mg/dL, which accords with the fluctuation range of Cglu in human blood. In this way, the shape-memory hydrogels could play a role in future diabetes treatment options. %0 journal article %@ 1616-5187 %A Löwenberg, C., Tripodo, G., Julich-Gruner, K., Neffe, A., Lendlein, A. %D 2020 %J Macromolecular Bioscience %N 10 %P 2000221 %R doi:10.1002/mabi.202000221 %T Supramolecular Gelatin Networks Based on Inclusion Complexes %U https://doi.org/10.1002/mabi.202000221 10 %X Hydrogel forming physical networks based on gelatin are an attractive approach toward multifunctional biomaterials with the option of reshaping, self‐healing, and stimuli‐sensitivity. However, it is challenging to design such gelatin‐based hydrogels to be stable at body temperature. Here, gelatin functionalized with desaminotyrosine (DAT) or desaminotyrosyl tyrosine (DATT) side chains is crosslinked with cyclodextrin (CD) dimers under formation of inclusions complexes. The supramolecular networks displayed at room temperature decreased water uptake (200–600 wt% for DAT‐based systems, 200 wt% for DATT based systems), and increased storage moduli up to 25.6 kPa determined by rheology compared to DAT(T) gelatin. The gel–sol transition temperature increased from 33 up to 42 °C. The presented system that is completely based on natural building blocks may form the basis for materials that may potentially respond by dissolution or changes of properties to changes in environmental conditions or to the presence of CD guest molecules. %0 journal article %@ 0014-3057 %A Izraylit, V., Hommes-Schattmann, P., Neffe, A., Gould, O., Lendlein, A. %D 2020 %J European Polymer Journal %P 109916 %R doi:10.1016/j.eurpolymj.2020.109916 %T Polyester urethane functionalizable through maleimide side-chains and cross-linkable by polylactide stereocomplexes %U https://doi.org/10.1016/j.eurpolymj.2020.109916 %X Sustainable multifunctional alternatives to fossil-derived materials, which can be functionalized and are degradable, can be envisioned by combining naturally derived starting materials with an established polymer design concept. Modularity and chemical flexibility of polyester urethanes (PEU) enable the combination of segments bearing functionalizable moieties and the tailoring of the mechanical and thermal properties. In this work, a PEU multiblock structure was synthesized from naturally derived L-lysine diisocyanate ethyl ester (LDI), poly(L-lactide) diol (PLLA) and N-(2,3-dihydroxypropyl)-maleimide (MID) in a one-step reaction. A maleimide side-chain (MID) provided a reactive site for the catalyst-free coupling of thiols shown for L-cysteine with a yield of 94%. Physical cross-links were generated by blending the PEU with poly(D-lactide) (PDLA), upon which the PLLA segments of the PEU and the PDLA formed stereocomplexes. Stereocomplexation occurred spontaneously during solution casting and was investigated with WAXS and DSC. Stereocomplex crystallites were observed in the blends, while isotactic PLA crystallization was not observed. The presented material platform with tailorable mechanical properties by blending is of specific interest for engineering biointerfaces of implants or carrier systems for bioactive molecules. %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2020 %J Besuch des Leistungskurs Chemie der Maxim-Gorki Gesamtschule Kleinmachnow %T Kunststoffe in der Medizin %U %X %0 journal article %@ 1022-1352 %A Abd-El-Aziz, A.S., Antonietti, M., Barner-Kowollik, C., Binder, W.H., Böker, A., Boyer, C., Buchmeiser, M.R., Cheng, S.Z.D., D’Agosto, F., Floudas, G., Frey, H., Galli, G., Genzer, J., Hartmann, L., Hoogenboom, R., Ishizone, T., Kaplan, D.L., Leclerc, M., Lendlein, A., Liu, B., Long, T.E., Ludwigs, S., Lutz, J.-F., Matyjaszewski, K., Meier, M.A.R., Müllen, K., Müllner, M., Rieger, B., Russell, T.P., Savin, D.A., Schlüter, A.D., Schubert, U.S., Seiffert, S., Severing, K., Soares, J.B.P., Staffilani, M., Sumerlin, B.S., Sun, Y., Tang, B.Z., Tang, C., Théato, P., Tirelli, N., Tsui, O.K.C., Unterlass, M.M., Vana, P., Voit, B., Vyazovkin, S., Weder, C., Wiesner, U., Wong, W.-Y., Wu, C., Yagci, Y., Yuan, J., Zhang, G. %D 2020 %J Macromolecular Chemistry and Physics %N 16 %P 2000216 %R doi:10.1002/macp.202000216 %T The Next 100 Years of Polymer Science %U https://doi.org/10.1002/macp.202000216 16 %X The year 2020 marks the 100th anniversary of the first article on polymerization, published by Hermann Staudinger. It is Staudinger who realized that polymers consist of long chains of covalently linked building blocks. Polymers have had a tremendous impact on the society ever since this initial publication. People live in a world that is almost impossible to imagine without synthetic polymers. But what does the future hold for polymer science? In this article, the editors and advisory board of Macromolecular Chemistry and Physics reflect on this question. %0 journal article %@ 0032-3861 %A Izraylit, V., Heuchel, M., Gould, O., Kratz, K., Lendlein, A. %D 2020 %J Polymer %P 122984 %R doi:10.1016/j.polymer.2020.122984 %T Strain recovery and stress relaxation behaviour of multiblock copolymer blends physically cross-linked with PLA stereocomplexation %U https://doi.org/10.1016/j.polymer.2020.122984 %X Polylactide (PLA) stereocomplexes have attracted attention due to their ability to improve the thermal stability of bioplastics. Here, we evaluate whether PLA stereocomplexes can form stable physical cross-links in blends of a multiblock copolymer with poly(l-lactide) and poly(ε-caprolactone) segments (PLLA-PCL) and a poly(d-lactide) oligomer (PDLA). Through the investigation of the strain recovery in step-cycle experiments and compliance of stress relaxation behaviour with a three-component model for the deformation of semi-crystalline polymers, PLA stereocomplexes were found to possess sufficient stability in the true strain range εH < 2.25 to be described as firm physical netpoints at 70 °C in the studied blends with PLA stereocomplex content ϕc SC ≥ 1.1 wt%, when the PCL domains are melted. Limiting ϕc SC ≤ 6 wt% broadens the behaviour inherent to elastic cross-linked networks to the strain values up until breakage of the samples, while the increase of ϕc SC triggers plastic deformations typical for semi-crystalline polymers. Redistributing of internal stresses from the amorphous to crystalline domains at increase of ϕc calculated with the adopted model was identified as reason of PLA stereocomplexes failure as stable physical network junctions at higher ϕc SC. Within the experimentally determined strain and composition ranges, in which PLA stereocomplexes possess structural stability, they can form robust cross-links in a polymer network. The knowledge gained here provides valuable design criteria for multifunctional thermoplastic elastomers. %0 journal article %@ 0032-3861 %A Kratz, K., Heuchel, M., Weigel, T., Lendlein, A. %D 2020 %J Polymer %P 123045 %R doi:10.1016/j.polymer.2020.123045 %T Surface hydrophilization of highly porous poly(ether imide) microparticles by covalent attachment of poly(vinyl pyrrolidone) %U https://doi.org/10.1016/j.polymer.2020.123045 %X Here we report on the hydrophilic surface functionalization of porous poly (ether imide) (PEI) microparticles, having a mean diameter of 226 ± 14 μm, a porosity of around 84 ± 2% with a mean pore diameter of 230 ± 40 nm, by covalent attachment of amino-terminated poly (vinyl pyrrolidone) (PVP–NH2) with a number average molecular weight of Mn = 5400 g mol−1. X-ray photoelectron spectroscopy confirmed a successful surface modification by a change in the surface chemistry, in particular the N/C ratio. The PEI-PVP particles exhibited an advancing water contact angle of θadv = 75° ± 5° as determined in environmental scanning electron microscopy microwetting experiments. The obtained results from mercury intrusion porosimetry and nitrogen adsorption experiments documented the preservation of the porous structure of the particles in the cause of the modification, which could be visualized by electron microscopy. The presented approach enables a covalent hydrophilization of porous particles while preserving their nanoporous morphology. %0 journal article %@ 2059-8521 %A Xu, X., Wang, W., Nie, Y., Kratz, K., Ma, N., Lendlein, A. %D 2020 %J MRS Advances %N 12 - 13 %P 643-653 %R doi:10.1557/adv.2019.446 %T Fine-tuning of Rat Mesenchymal Stem Cell Senescence via Microtopography of Polymeric Substrates %U https://doi.org/10.1557/adv.2019.446 12 - 13 %X Cellular senescence, a driver of aging and age-related diseases, is a stable state found in metabolically active cells characterized by irreversible cell growth arrest and dramatic changes in metabolism, gene expression and secretome profile. Endogenous regeneration efficacy of mesenchymal stem cells (MSCs) could be attenuated due to senescence. MSCs can be modulated by not only biochemical signals but also by physical cues such as substrate topography. To provide a cell culture substrate that can prevent MSC senescence over an extended period of in vitro cultivation, here, the cell- and immunocompatible poly(ether imide) (PEI) substrate was used. Two distinct levels of roughness were created on the bottom surfaces of PEI inserts via injection molding: Low-R (similar to the thickness of attached single MSC, Rq: 3.9 ± 0.2 µm) and High-R (larger than single MSC thickness. Rq: 22.7 ± 0.8 µm). Cell expansion, lysosomal enzymatic activity, apoptosis and paracrine effects of senescent MSCs were examined by cell counting, detection of senescence-associated β-galactosidase (SA β-gal), Caspase 3/7, and CFSE labeling. MSCs showed high cell viability and similar spindle-shaped morphology on all investigated surfaces. Cells on Low-R presented the highest expansion (80000 ± 1805 cells), as compared to cells on smooth PEI and High-R. The low apoptosis level (0.08 vs 0.12 from smooth PEI) and senescence ratio (35% vs. 54% from smooth PEI) were observed in MSCs cultured on Low-R. The secretome from Low-R effectively prevents senescence and supports the proliferation of neighboring cells (1.5-fold faster) as compared to the smooth PEI secretome. In summary, the Low-R PEI provided a superior surface environment for MSCs, which promoted proliferation, inhibited apoptosis and senescence, and effectively influenced the proliferation of neighboring cells via their paracrine effect. Such microroughness can be considered as a key parameter for improving the therapeutic potential of endogenous regeneration, anti-organismal aging and anti-age-related pathologies via directly promoting cell growth and modulating paracrine effects of the senescence associated secretome. %0 journal article %@ 1042-3931 %A Curio, J., Tarar, W., Al-Hindwan, H., Neumann, R., Berger, C., Hoting, M., Kasner, M., Lendlein, A., Landmesser, U., Reinthaler, M. %D 2020 %J The Journal of Invasive Cardiology %N 1 %P E1-E8 %T The MitraClip Procedure in Patients With Moderate Resting but Severe Exercise-Induced Mitral Regurgitation %U 1 %X Background. Optimal timing for percutaneous mitral regurgitation (MR) treatment using MitraClip (Abbott Vascular) remains unclear. We evaluated the outcome after MitraClip in patients with moderate resting MR, progressing to severe exercise-induced MR (MR2+) compared to patients with severe resting MR (MR3). Methods. We retrospectively investigated 221 patients undergoing MitraClip. All-cause deaths and heart failure (HF) hospitalizations were assessed as the combined primary endpoint. Results. We identified 55 MR2+ and 166 MR3 patients. At baseline, MR3 patients showed higher STS scores (6.7 ± 7.3 vs 4.4 ± 5.5; P<.01), more HF hospitalizations in the 2 years prior to the procedure (51% vs 29%; P<.01), worse left ventricular ejection fraction (44.9 ± 16.5% vs 52.5 ± 14.3%; P<.01), larger left ventricular end-diastolic diameter (LVEDd; 57.0 ± 9.3 mm vs 51.7 ± 8.2 mm; P<.001), and larger left atrial volumes (118.3 ± 55.8 mL vs 98.6 ± 35.2 mL; P=.02). Long-term outcome according to the combined endpoint was significantly worse in MR3 patients (P=.01). HF hospitalizations significantly declined in both groups 2 years after MitraClip (P<.001 in MR3 patients, P=.03 in MR2+ patients). Multivariate Cox regression analysis revealed LVEDd (hazard ratio, 1.035; 95% confidence interval, 1.005-1.066; P=.02) and previous HF hospitalizations (hazard ratio, 1.813; 95% confidence interval, 1.016-3.234; P=.04) as strong outcome predictors. Conclusions. Symptomatic patients with moderate resting and severe exercise-induced MR during handgrip echocardiography may represent an MR cohort at an earlier disease stage with improved treatment response following MitraClip implantation compared to individuals with severe resting MR. Larger left ventricular diameters and preprocedural HF hospitalizations were identified as independent adverse outcome predictors. %0 journal article %@ 2059-8521 %A Tarazona, N., Machatschek, R., Lendlein, A. %D 2020 %J MRS Advances %N 11 -12 %P 667-677 %R doi:10.1557/adv.2019.458 %T Relation between Surface Area and Surface Potential Change during (co)Polyesters Degradation as Langmuir Monolayer %U https://doi.org/10.1557/adv.2019.458 11 -12 %X Polyhydroxyalkanoates (PHAs) are degradable (co)polyesters synthesized by microorganisms with a variety of side-chains and co-monomer ratios. PHAs can be efficiently hydrolyzed under alkaline conditions and by PHA depolymerase enzymes, altering their physicochemical properties. Using 2D Langmuir monolayers as model system to study the degradation behavior of macromolecules, we aim to describe the the interdependency between the degradation of two PHAs and the surface potential, which influences material-proteins interaction and cell response. We hypothesize that the mechanism of hydrolysis of the labile ester bonds in (co)polyesters defines the evolution of the surface potential, owing to the rate of accumulation of charged insoluble degradation products. The alkaline hydrolysis and the enzymatically catalyzed hydrolysis of PHAs were previously defined as chain-end scission and random-scission mechanisms, respectively. In this study, these two distinct scenarios are used to validate our model. The surface potential change during the chain-end scission of poly(3-R-hydroxybutyrate) (PHB) under alkaline conditions was compared to that of the enzymatically catalyzed hydrolysis (random-scission) of poly[(3-R-hydroxyoctanoate)-co-(3-R-hydroxyhexanoate)] (PHOHHx), using the Langmuir monolayer technique. In the random-scission mechanism the dissolution of degradation products, measured as a decrease in the area per molecule, was preceded by a substantial change of the surface potential, provoked by the negative charge of the broken ester bonds accumulated in the air-water interface. In contrast, when chains degraded via the chain-ends, the surface potential changed in line with the dissolution of the material, presenting a kinetic dependent on the surface area of the monolayers. These results provide a basis for understanding PHAs degradation mechanism. Future research on (co)polymers with different main-chain lengths might extend the elucidation of the surface potential development of (co)polyesters as Langmuir monolayer. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2020 %J Living Machines 2020; Growing Structures: bioinspired innovation insights for architecture and robotics %T Active biomaterials for growing robots %U %X %0 journal article %@ 1386-0291 %A Lau, S., Rangarajan, R., Krüger-Genge, A., Braune, S., Küpper, J., Lendlein, A., Jung, F. %D 2020 %J Clinical Hemorheology and Microcirculation %N 1 %P 93-107 %R doi:10.3233/CH-199238 %T Age-related morphology and function of human arterial endothelial cells %U https://doi.org/10.3233/CH-199238 1 %X According to the assays applied here, HAEC from young and elderly donors up to the age of 63 years could be judged equally suitable for autologous cellularization strategies. However, this finding should be regarded with caution due to the extremely large variability between individual donors. Further studies comprising a larger sample size are necessary to investigate this issue more thoroughly. %0 journal article %@ 2059-8521 %A Nie, Y., Deng, Z., Wang, W., Bhuvanesh, T., Ma, N., Lendlein, A. %D 2020 %J MRS Advances %N 12 - 13 %P 591-599 %R doi:10.1557/adv.2019.405 %T Polydopamine-mediated Surface Modification Promotes the Adhesion and Proliferation of Human Induced Pluripotent Stem Cells %U https://doi.org/10.1557/adv.2019.405 12 - 13 %X With their abilities of self-renewal and pluripotency to differentiate into all three germ layers, human induced pluripotent stem cells (hiPSCs) are a promising cell source for cell-based drug and implant testing. However, the large-scale expansion and maintenance of hiPSCs requires following strict protocols. There is high demand for advanced cell culture systems capable of generating high-quality hiPSCs to meet application requirements. In this study, we probe the possibility of modifying polymeric substrates for maintaining the self-renewal and pluripotency of hiPSCs. Here, polydopamine (PDA) was employed to immobilize the Laminin 521 (LN521) onto the surface of polyethylene terephthalate (PET). An aqueous solution of dopamine with concentrations ranging from 0 to 2.0 mg/mL was applied on PET surfaces. These PDA-modified surfaces were further functionalized with LN521. Surface wettability was evaluated by measuring the water contact angle (WCA) and surface properties of the modified substrate were analyzed using an atomic force microscope (AFM). Initial hiPSC attachment (1h after seeding) and cell proliferation were evaluated by counting the total cell number. The maintenance of pluripotency was evaluated at designed time points. WCA of the PDA-LN521 surfaces gradually decreased from 62.1°±6.3° to 8.1°±2.9°. The maximum peak-to-valley height roughness (Rt) of those surfaces determined by AFM increased in a dopamine-concentration-dependent manner, ranging from 43.9±1.6 nm to 126.7±7.6 nm. The Young’s modulus of these surfaces was substantially increased from 0.98±0.36 GPa to 4.81±2.41 GPa. There was a significant enhancement (13.0±7.2% and 24.2±8.1%) of hiPSC adhesion on PDA-LN521 (dopamine concentration at 0.125 and 0.25 mg/mL). When increasing the dopamine concentration to 0.5 and 1.0 mg/mL, there was no further increase in hiPSC adhesion on PDA-LN521 surfaces. Moreover, hiPSC proliferation was remarkably enhanced on PDA-LN521 surface (dopamine solution at concentration from 0.125 to 1.0 mg/mL). Pluripotency of hiPSCs was not affected by PDA treatment. In conclusion, PDA-mediated surface modification is an effective approach for the robust expansion and maintenance of hiPSCs on polymer substrates. %0 journal article %@ 2059-8521 %A Zou, J., Wang, W., Sun, X., Tung, W., Ma, N., Lendlein, A. %D 2020 %J MRS Advances %N 12 - 13 %P 601-607 %R doi:10.1557/adv.2019.402 %T AFM Assessment of the Mechanical Properties of Stem Cells During Differentiation %U https://doi.org/10.1557/adv.2019.402 12 - 13 %X The dynamic mechanical force transmitted through microenvironments during tissue formation and regeneration continuously impacts the mechanics of cells and thereby regulates gene and protein expression. The mechanical properties are altered during the process of stem cells differentiating into different lineages. At different stages of differentiation, stem cells display different mechanical properties in response to surrounding microenvironments, which depend on the subcellular structures, especially the cytoskeleton and nucleus. The mechanical properties of the cell nucleus affect protein folding and transport as well as the condensation of chromatin, through which the cell fate is regulated. These findings raise the question as to how cell mechanics change during differentiation. In this study, the mechanical properties of human bone marrow mesenchymal stem cells (hBMSCs) were determined during adipogenic and osteogenic differentiation by atomic force microscopy (AFM). The cytoskeletal structure and the modification of histone were investigated using laser confocal microscope and flow cytometry. The mechanical properties of cell nuclei at different stages of cell differentiation were compared. The stiffness of nuclei increased with time as osteogenesis was induced in hBMSCs. The H3K27me3 level increased during osteogenesis and adipogenesis according to flow cytometry analysis. Our results show conclusively that AFM is a facile and effective method to monitor stem cell differentiation. The measurement of cell mechanical properties by AFM improves our understanding on the connection between mechanics and stem cell fate. %0 journal article %@ 2059-8521 %A Bhuvanesh, T., Machatschek, R., Liu, Y., Ma, N., Lendlein, A. %D 2020 %J MRS Advances %N 12 - 13 %P 609-620 %R doi:10.1557/adv.2019.401 %T Self-stabilized fibronectin films at the air/water interface %U https://doi.org/10.1557/adv.2019.401 12 - 13 %X Fibronectin (FN) is a mediator molecule, which can connect cell receptors to the extracellular matrix (ECM) in tissues. This function is highly desirable for biomaterial surfaces in order to support cell adhesion. Controlling the fibronectin adsorption profile on substrates is challenging because of possible conformational changes after deposition, or due to displacement by secondary proteins from the culture medium. Here, we aim to develop a method to realize self-stabilized ECM glycoprotein layers with preserved native secondary structure on substrates. Our concept is the assembly of FN layers at the air-water (A-W) interface by spreading FN solution as droplets on the interface and transfer of the layer by the Langmuir-Schäfer (LS) method onto a substrate. It is hypothesized that 2D confinement and high local concentration at A-W interface supports FN self-interlinking to form cohesive films. Rising surface pressure with time, plateauing at 10.5 mN·m-1 (after 10 hrs), indicated that FN was self-assembling at the A-W interface. In situ polarization-modulation infrared reflection absorption spectroscopy of the layer revealed that FN maintained its native anti-parallel β-sheet structure after adsorption at the A-W interface. FN self-interlinking and elasticity was shown by the increase in elastic modulus and loss modulus with time using interfacial rheology. A network-like structure of FN films formed at the A-W interface was confirmed by atomic force microscopy after LS transfer onto Si-wafer. FN films consisted of native, globular FN molecules self-stabilized by intermolecular interactions at the A-W interface. Therefore, the facile FN self-stabilized network-like films with native anti-parallel β-sheet structure produced here, could serve as stable ECM protein coatings to enhance cell attachment on in vitro cell culture substrates and planar implant materials. %0 journal article %@ 2059-8521 %A Bäckemo, J., Heuchel, M., Reinthaler, M., Kratz, K., Lendlein, A. %D 2020 %J MRS Advances %N 12 - 13 %P 621-632 %R doi:10.1557/adv.2019.433 %T Predictive topography impact model for Electrical Discharge Machining (EDM) of metal surfaces %U https://doi.org/10.1557/adv.2019.433 12 - 13 %X Electrical discharge machining (EDM) is a method capable of modifying the microstructure of metal surfaces. Here, we present a predictive computer supported model of the roughness generated on the surface by this process. EDM is a stochastic process, in which charge generated between a metallic substrate and an electrode creates impacts, and thus is suitable for modeling through iterative simulations. The resulting virtual, modified surface structures were evaluated for roughness. Curvatures were analyzed using Abbott-Firestone curves. Three radii of impacts (10, 20, 30 μm) and two values for the depth to radius ratio (0.1, 0.3) were used as input parameters to compute a total of six simulations. It was found that the roughness parameters followed an inverse exponential trend as a function of impact number, and that the strongly concave curvatures reached equilibrium at an earlier impact number for lower depth to radius ratios. %0 journal article %@ 1386-0291 %A Sun, X., Tung, W., Zou, J., Wang, W., Kratz, K., Ma, N., Lendlein, A. %D 2020 %J Clinical Hemorheology and Microcirculation %N 4 %P 405-415 %R doi:10.3233/CH-190696 %T Elasticity of fiber meshes from multiblock copolymers influences endothelial cell behavior %U https://doi.org/10.3233/CH-190696 4 %X These results suggested that tuning the fiber meshes’ elasticity might be a potential strategy for modulating the formation or regeneration of blood vessels. %0 journal article %@ 1022-1336 %A Razzaq, M., Behl, M., Heuchel, M., Lendlein, A. %D 2020 %J Macromolecular Rapid Communications %N 1 %P 1900440 %R doi:10.1002/marc.201900440 %T Matching Magnetic Heating and Thermal Actuation for Sequential Coupling in Hybrid Composites by Design %U https://doi.org/10.1002/marc.201900440 1 %X Sequentially coupling two material functions requires matching the output from the first with the input of the second function. Here, magnetic heating controls thermal actuation of a hybrid composite in a challenging system environment causing an elevated level of heat loss. The concept is a hierarchical design consisting of an inner actuator of nanocomposite material, which can be remotely heated by exposure to an alternating magnetic field (AMF) and outer layers of a porous composite system with a closed pore morphology. These porous layers act as heat insulators and as barriers to the surrounding water. By exposure to the AMF, a local bulk temperature of 71 °C enables the magnetic actuation of the device, while the temperature of the surrounding water is kept below 50 °C. Interestingly, the heat loss during magnetic heating leads to an increase of the water phase (small volume) temperature. The temperature increase is able to sequentially trigger an adjacent thermal actuator attached to the actuator composite. In this way it could be demonstrated how the AMF is able to initiate two kinds of independent actuations, which might be interesting for robotics operating in aqueous environments. %0 journal article %@ 0887-2333 %A Lau, S., Rangarajan, R., Philidet, C., Krüger-Genge, A., Braune, S., Kammerer, S., Küpper, J., Lendlein, A., Jung, F. %D 2020 %J Toxicology in Vitro %P 104685 %R doi:10.1016/j.tiv.2019.104685 %T Effects of acrolein in comparison to its prodrug cyclophosphamide on human primary endothelial cells in vitro %U https://doi.org/10.1016/j.tiv.2019.104685 %X High doses of acrolein led to HUVEC death and loss of vWF production. This effect might be associated with the increased incidence of thromboembolic events in cancer patients treated with high doses of CPA. %0 journal article %@ 2059-8521 %A Pang, J., Wischke, C., Lendlein, A. %D 2020 %J MRS Advances %N 12 - 13 %P 633-642 %R doi:10.1557/adv.2019.441 %T In vitro Degradation Analysis of 3D-architectured Gelatin-based Hydrogels %U https://doi.org/10.1557/adv.2019.441 12 - 13 %X Multifunctional biopolymer-based materials are promising candidates for next generation regenerative biomaterials. Understanding the degradation behavior of biomaterials is vital for ensuring biological safety, as well as for better control of degradation properties based on rational design of a material’s physical and chemical characteristics. In this study, we decipher the degradation of a hydrogel prepared from gelatin and lysine diisocyanate ethyl ester (LDI) using in vitro models, which simulate hydrolytic, oxidative and enzymatic degradation (collagenase). Gravimetrical, morphological, mechanical and chemical properties were evaluated. Notably, the hydrogels were relatively resistant to hydrolytic degradation, but degraded rapidly within 21 days (>95% mass loss) under oxidative and collagenase degradation. Oxidative and collagenase degradation rapidly decreased the storage and loss modulus of the hydrogels, and slightly increased their viscous component (tan δ). For each degradation condition, the results suggest different possible degradation pathways associated to the gelatin polypeptide backbone, urea linkages and ester groups. The primary degradation mechanisms for the investigated gelatin based hydrogels are oxidative and enzymatic in nature. The relative hydrolytic stability of the hydrogels should ensure minimal degradation during storage and handling prior to application in surgical theatres. %0 journal article %@ 2059-8521 %A Balk, M., Behl, M., Lendlein, A. %D 2020 %J MRS Advances %N 12 - 13 %P 655-666 %R doi:10.1557/adv.2019.447 %T Actuators Based on Oligo[(epsilon-caprolactone)-co-glycolide] with Accelerated Hydrolytic Degradation %U https://doi.org/10.1557/adv.2019.447 12 - 13 %X In this work, glycolide units were incorporated in poly(ε-caprolactone) based actuator materials in order to achieve an accelerated hydrolytic degradation and to explore the function-function relationship. Three different oligo[(ε-caprolactone)-co-glycolide] copolymers (OCGs) with similar molecular weights (10.5 ± 0.5 kg∙mol−1) including a glycolide content of 8, 16, and 26 mol% (ratio 1:1:1 wt%) terminated with methacrylated moieties were crosslinked. The obtained actuators provided a broad melting transition in the range from 27 to 44 °C. The hydrolytic degradation of programmed OCG actuators (200% of elongation) resulted in a reduction of sample mass to 51 wt% within 21 days at pH = 7.4 and 40 °C. Degradation results in a decrease of Tm associated to the actuating units and increasing Tm associated to the skeleton forming units. The actuation capability decreased almost linear as function of time. After 11 days of hydrolytic degradation the shape-memory functionality was lost. Accordingly, a fast degradation behaviour as required, e.g., for actuator materials intended as implant material can be realized. %0 journal article %@ 0168-3659 %A Machatschek, R., Lendlein, A. %D 2020 %J Journal of Controlled Release %P 276-284 %R doi:10.1016/j.jconrel.2019.12.044 %T Fundamental insights in PLGA degradation from thin film studies %U https://doi.org/10.1016/j.jconrel.2019.12.044 %X Poly(lactide-co-glycolide)s are commercially available degradable implant materials, which are typically selected based on specifications given by the manufacturer, one of which is their molecular weight. Here, we address the question whether variations in the chain length and their distribution affect the degradation behavior of Poly[(rac-lactide)-co-glycolide]s (PDLLGA). The hydrolysis was studied in ultrathin films at the air-water interface in order to rule out any morphological effects. We found that both for purely hydrolytic degradation as well as under enzymatic catalysis, the molecular weight has very little effect on the overall degradation kinetics of PDLLGAs. The quantitative analysis suggested a random scission mechanism. The monolayer experiments showed that an acidic micro-pH does not accelerate the degradation of PDLLGAs, in contrast to alkaline conditions. The degradation experiments were combined with interfacial rheology measurements, which showed a drastic decrease of the viscosity at little mass loss. The extrapolated molecular weight behaved similar to the viscosity, dropping to a value near to the solubility limit of PDLLGA oligomers before mass loss set in. This observation suggests a solubility controlled degradation of PDLLGA. Conclusively, the molecular weight affects the degradation of PDLLGA devices mostly in indirect ways, e.g. by determining their morphology and porosity during fabrication. Our study demonstrates the relevance of the presented Langmuir degradation method for the design of controlled release systems. %0 journal article %@ 2059-8521 %A Machatschek, R., Saretia, S., Lendlein, A. %D 2020 %J MRS Advances %N 11 - 12 %P 679-691 %R doi:10.1557/adv.2019.457 %T The interplay between network morphology and degradation kinetics of polymers: Theoretical and experimental analysis by means of a 2D model system %U https://doi.org/10.1557/adv.2019.457 11 - 12 %X Network formation by cross-linking is a common method to incorporate functions like elastic deformability, shape-memory capability or hydrogel formation into polymer materials for medical applications. Since these materials are often intended to degrade, their design would benefit from a quantitative prediction of the interdependence between network architecture and degradation behavior. Here, we introduce a quantitative description of the degradation behavior of polymer networks. A simplified model was developed under the assumption of having an ideal network, where all network strands are terminated by network nodes and each node is connected to the same number of strands. To describe the degradation of real networks, the model was modified by allowing for a varying connectivity of network nodes, which also included free chain-ends. The models were validated by comparison with Langmuir monolayer degradation data from 2D networks formed by cross-linking oligo(ε-caprolactone)diols with dialdehydes. We found that both the ideal network hypothesis and the real network model were in excellent agreement with the experimental data, with the ideal network hypothesis requiring longer network strands than the real network to result in the same degradation behavior. The models were further used to calculate the degradation curves of the corresponding, non cross-linked molecules. By comparison, it was found that the network formation increases the time required to reach 50% degradation of oligo(ε-caprolactone)diols by only 20%. This difference mainly arises from attaching free chain ends to network points. %0 journal article %@ 2059-8521 %A Behl, M., Razzaq, M., Mazurek-Budzyñska, M., Lendlein, A. %D 2020 %J MRS Advances %N 45 %P 2317-2330 %R doi:10.1557/adv.2020.345 %T Polyetheresterurethane Based Porous Scaffolds with Tailorable Architectures by Supercritical CO2 Foaming %U https://doi.org/10.1557/adv.2020.345 45 %X Porous three-dimensional (3D) scaffolds are promising treatment options in regenerative medicine. Supercritical and dense-phase fluid technologies provide an attractive alternative to solvent-based scaffold fabrication methods. In this work, we report on the fabrication of poly-etheresterurethane (PPDO-PCL) based porous scaffolds with tailorable pore size, porosity, and pore interconnectivity by using supercritical CO2 (scCO2) fluid-foaming. The influence of the processing parameters such as soaking time, soaking temperature and depressurization on porosity, pore size, and interconnectivity of the foams were investigated. The average pore diameter could be varied between 100–800 μm along with a porosity in the range from (19 ± 3 to 61 ± 6)% and interconnectivity of up to 82%. To demonstrate their applicability as scaffold materials, selected foams were sterilized via ethylene oxide sterilization. They showed negligible cytotoxicity in tests according to DIN EN ISO 10993-5 and 10993-12 using L929 cells. The study demonstrated that the pore size, porosity and the interconnectivity of this multi-phase semicrystalline polymer could be tailored by careful control of the processing parameters during the scCO2 foaming process. In this way, PPDO-PCL scaffolds with high porosity and interconnectivity are potential candidate materials for regenerative treatment options. %0 journal article %@ 1525-7797 %A Tarazona, N., Machatschek, R., Lendlein, A. %D 2020 %J Biomacromolecules %N 2 %P 761-771 %R doi:10.1021/acs.biomac.9b01458 %T Unraveling the Interplay between Abiotic Hydrolytic Degradation and Crystallization of Bacterial Polyesters Comprising Short and Medium Side-Chain-Length Polyhydroxyalkanoates %U https://doi.org/10.1021/acs.biomac.9b01458 2 %X Polyhydroxyalkanoates (PHAs) have attracted attention as degradable (co)polyesters which can be produced by microorganisms with variations in the side chain. This structural variation influences not only the thermomechanical properties of the material but also its degradation behavior. Here, we used Langmuir monolayers at the air–water (A–W) interface as suitable models for evaluating the abiotic degradation of two PHAs with different side-chain lengths and crystallinity. By controlling the polymer state (semicrystalline, amorphous), the packing density, the pH, and the degradation mechanism, we could draw several significant conclusions. (i) The maximum degree of crystallinity for a PHA film to be efficiently degraded up to pH = 12.3 is 40%. (ii) PHA made of repeating units with shorter side-chain length are more easily hydrolyzed under alkaline conditions. The efficiency of alkaline hydrolysis decreased by about 65% when the polymer was 40% crystalline. (iii) In PHA films with a relatively high initial crystallinity, abiotic degradation initiated a chemi-crystallization phenomenon, detected as an increase in the storage modulus (E′). This could translate into an increase in brittleness and reduction in the material degradability. Finally, we demonstrate the stability of the measurement system for long-term experiments, which allows degradation conditions for polymers that could closely simulate real-time degradation. %0 journal article %@ 0027-8424 %A Deng, Z., Wang, W., Xu, X., Gould, O.E.C, Kratz, K., Ma, N., Lendlein, A. %D 2020 %J Proceedings of the National Academy of Sciences of the United States of America: PNAS %N 4 %P 1895-1901 %R doi:10.1073/pnas.1910668117 %T Polymeric sheet actuators with programmable bioinstructivity %U https://doi.org/10.1073/pnas.1910668117 4 %X Stem cells are capable of sensing and processing environmental inputs, converting this information to output a specific cell lineage through signaling cascades. Despite the combinatorial nature of mechanical, thermal, and biochemical signals, these stimuli have typically been decoupled and applied independently, requiring continuous regulation by controlling units. We employ a programmable polymer actuator sheet to autonomously synchronize thermal and mechanical signals applied to mesenchymal stem cells (MSCs). Using a grid on its underside, the shape change of polymer sheet, as well as cell morphology, calcium (Ca2+) influx, and focal adhesion assembly, could be visualized and quantified. This paper gives compelling evidence that the temperature sensing and mechanosensing of MSCs are interconnected via intracellular Ca2+. Up-regulated Ca2+ levels lead to a remarkable alteration of histone H3K9 acetylation and activation of osteogenic related genes. The interplay of physical, thermal, and biochemical signaling was utilized to accelerate the cell differentiation toward osteogenic lineage. The approach of programmable bioinstructivity provides a fundamental principle for functional biomaterials exhibiting multifaceted stimuli on differentiation programs. Technological impact is expected in the tissue engineering of periosteum for treating bone defects. %0 journal article %@ 2045-2322 %A Moradian, H., Roch, T., Lendlein, A., Gossen, M. %D 2020 %J Scientific Reports %P 4181 %R doi:10.1038/s41598-020-60506-4 %T mRNA Transfection-Induced Activation of Primary Human Monocytes and Macrophages: Dependence on Carrier System and Nucleotide Modification %U https://doi.org/10.1038/s41598-020-60506-4 %X Monocytes and macrophages are key players in maintaining immune homeostasis. Identifying strategies to manipulate their functions via gene delivery is thus of great interest for immunological research and biomedical applications. We set out to establish conditions for mRNA transfection in hard-to-transfect primary human monocytes and monocyte-derived macrophages due to the great potential of gene expression from in vitro transcribed mRNA for modulating cell phenotypes. mRNA doses, nucleotide modifications, and different carriers were systematically explored in order to optimize high mRNA transfer rates while minimizing cell stress and immune activation. We selected three commercially available mRNA transfection reagents including liposome and polymer-based formulations, covering different application spectra. Our results demonstrate that liposomal reagents can particularly combine high gene transfer rates with only moderate immune cell activation. For the latter, use of specific nucleotide modifications proved essential. In addition to improving efficacy of gene transfer, our findings address discrete aspects of innate immune activation using cytokine and surface marker expression, as well as cell viability as key readouts to judge overall transfection efficiency. The impact of this study goes beyond optimizing transfection conditions for immune cells, by providing a framework for assessing new gene carrier systems for monocyte and macrophage, tailored to specific applications. %0 journal article %@ 1525-7797 %A Seppälä, J., van Bochove, B., Lendlein, A. %D 2020 %J Biomacromolecules %N 2 %P 273-275 %R doi:10.1021/acs.biomac.9b01701 %T Developing Advanced Functional Polymers for Biomedical Applications %U https://doi.org/10.1021/acs.biomac.9b01701 2 %X %0 journal article %@ 1022-1336 %A Zhang, P., Behl, M., Balk, M., Peng, X., Lendlein, A. %D 2020 %J Macromolecular Rapid Communications %N 7 %P 1900658 %R doi:10.1002/marc.201900658 %T Shape‐Programmable Architectured Hydrogels Sensitive to Ultrasound %U https://doi.org/10.1002/marc.201900658 7 %X On‐demand motion of highly swollen polymer systems can be triggered by changes in pH, ion concentrations, or by heat. Here, shape‐programmable, architectured hydrogels are introduced, which respond to ultrasonic‐cavitation‐based mechanical forces (CMF) by directed macroscopic movements. The concept is the implementation and sequential coupling of multiple functions (swellability in water, sensitivity to ultrasound, shape programmability, and shape‐memory) in a semi‐interpenetrating polymer network (s‐IPN). The semi‐IPN‐based hydrogels are designed to function through rhodium coordination (Rh‐s‐IPNH). These coordination bonds act as temporary crosslinks. The porous hydrogels with coordination bonds (degree of swelling from 300 ± 10 to 680 ± 60) exhibit tensile strength σmax up to 250 ± 60 kPa. Shape fixity ratios up to 90% and shape recovery ratios up to 94% are reached. Potential applications are switches or mechanosensors. %0 journal article %@ 2666-3864 %A Machatschek, R., Schulz, B., Lendlein, A. %D 2020 %J Cell reports. Physical science %N 1 %P 100009 %R doi:10.1016/j.xcrp.2019.100009 %T Quantitative Model and Thin Film Studies Relating Molecular Architecture and Degradation of Multifunctional Materials %U https://doi.org/10.1016/j.xcrp.2019.100009 1 %X A characteristic of multifunctional polymer materials is their complex molecular architecture, which creates a challenge in predicting their degradation behavior. Hence, their appropriate design demands a quantitative correlation between their molecular architecture and their molecular degradation behavior. Here, we present a method to analyze and predict the degradation of such molecules by fast and conclusive Langmuir monolayer experiments in combination with kinetic models. Important findings include the retardation of the degradation in the early stage caused by high molecular weight as well as end caps. In multiblock copolymers consisting of fast- and slow-degrading blocks, the molecular weight and the block length have little effect on degradation behavior. In semicrystalline multiblock copolymers, the degradation rate of amorphous blocks is reduced compared to completely amorphous materials. The reaction rate constants that are obtained by this method are essential for predictive models for the degradation of multifunctional devices. %0 journal article %@ 1525-7797 %A Izraylit, V., Gould, O., Rudolph, T., Kratz, K., Lendlein, A. %D 2020 %J Biomacromolecules %N 2 %P 338-348 %R doi:10.1021/acs.biomac.9b01279 %T Controlling Actuation Performance in Physically Cross-Linked Polylactone Blends Using Polylactide Stereocomplexation %U https://doi.org/10.1021/acs.biomac.9b01279 2 %X Within the field of shape-changing materials, synthetic chemical modification has been widely used to introduce key structural units and subsequently expand the mechanical functionality of actuator devices. The introduction of architectural elements that facilitate in situ control over mechanical properties and complete geometric reconfiguration of a device is highly desirable to increase the morphological diversity of polymeric actuator materials. The subject of the present study is a multiblock copolymer with semicrystalline poly(l-lactide) and poly(ε-caprolactone) (PLLA–PCL) segments. By harnessing the stereocomplexation of copolymer chains with a poly(d-lactide) oligomer (PDLA), we provide anchoring points for physical network formation and demonstrate how a blending process can be used to efficiently vary the mechanical properties of a shape-memory actuator. We investigate the effect of molecular structure on the actuation performance of the material in cyclic thermomechanical tests, with a maximum reversible shape change εrev′ = 13.4 ± 1.5% measured at 3.1 wt % of polylactide stereocomplex content in the multiblock copolymer matrix. The thermophysical properties, crystalline structure, and phase morphology were analyzed by DSC, WAXS and AFM respectively, elucidating the structure-to-function relationship in physically cross-linked blended materials. The work demonstrates a one-step technique for manufacturing a polymeric actuator and tuning its performance in situ. This approach should greatly improve the efficiency of physically cross-linked actuator fabrication, allowing composition and physical behavior to be precisely and easily controlled. %0 journal article %@ 2059-8521 %A Izraylit, V., Gould, O., Kratz, K., Lendlein, A. %D 2020 %J MRS Advances %N 14 - 15 %P 699-707 %R doi:10.1557/adv.2019.465 %T Investigating the Phase-Morphology of PLLA-PCL Multiblock Copolymer / PDLA Blends Cross-linked Using Stereocomplexation %U https://doi.org/10.1557/adv.2019.465 14 - 15 %X The macroscale function of multicomponent polymeric materials is dependent on their phase-morphology. Here, we investigate the morphological structure of a multiblock copolymer consisting of poly(L-lactide) and poly(ε-caprolactone) segments (PLLA-PCL), physically cross-linked by stereocomplexation with a low molecular weight poly(D-lactide) oligomer (PDLA). The effects of blend composition and PLLA-PCL molecular structure on the morphology are elucidated by AFM, TEM and SAXS. We identify the formation of a lattice pattern, composed of PLA domains within a PCL matrix, with an average domain spacing d0 = 12 – 19 nm. The size of the PLA domains were found to be proportional to the block length of the PCL segment of the copolymer and inversely proportional to the PDLA content of the blend. Changing the PLLA-PCL / PDLA ratio caused a shift in the melt transition Tm attributed to the PLA stereocomplex crystallites, indicating partial amorphous phase dilution of the PLA and PCL components within the semicrystalline material. By elucidating the phase structure and thermal character of multifunctional PLLA-PCL / PDLA blends, we illustrate how composition affects the internal structure and thermal properties of multicomponent polymeric materials. This study should facilitate the more effective incorporation of a variety of polymeric structural units capable of stimuli responsive phase transitions, where an understanding the phase-morphology of each component will enable the production of multifunctional soft-actuators with enhanced performance. %0 journal article %@ 2059-8521 %A Wischke, C., Kersting, M., Welle, A., Lysyakova, L., Braune, S., Kratz, K., Jung, F., Franzreb, M., Lendlein, A. %D 2020 %J MRS Advances %N 14 - 15 %P 773-783 %R doi:10.1557/adv.2020.218 %T Thin hydrogel coatings formation catalyzed by immobilized enzyme horseradish peroxidase %U https://doi.org/10.1557/adv.2020.218 14 - 15 %X Enzymes can be a renewable source of catalytic agents and thus be interesting for sustainable approaches to create and modify functional materials. Here, thin hydrogel layers were prepared as thin coatings on hard substrates by immobilized horseradish peroxidase. Hydrophilic 4-arm star shaped telechelics from oligo(ethylene glycol) bearing on average 55% end groups derived from aromatic amino acids served as monomers and enzymatic substrates. Shifts of the contact angle from 84° to 62° for the wetting process and of zeta potential towards the neutral range illustrated an alteration of physicochemical properties of the model surfaces by a hydrophilic shielding. Time-of-flight secondary ion mass spectrometry (ToF-SIMS), quartz crystal microbalance and atomic force microscopy (AFM) experiments enabled the qualitative and quantitative proof of hydrogel deposition at the interface with thicknesses in the medium nanometer size range. Conceptually, as the immobilized enzyme becomes entrapped in the hydrogel and the crosslinking mechanism bases on a radical reaction after enzymatic activation of the monomers with a limited diffusivity and lifetime, the formed network material can be assumed to be inhomogeneous on the molecular level. On the macroscale, however, relative homogeneity of the coating was observed via ToF-SIMS and AFM mapping. As an exemplary functional evaluation in view of bioanalytical applications, the thrombogenicity of the coating was studied in static tests with human blood from several donors. In the future, this “coating-from” approach may be explored for cell culture substrate coatings, for protein/biofilm repellence in technical applications, or in bioanalytical devices. %0 journal article %@ 1386-0291 %A Nie, Y., Xu, X., Wang, W., Ma, N., Lendlein, A. %D 2020 %J Clinical Hemorheology and Microcirculation %N 2 %P 329-340 %R doi:10.3233/CH-209217 %T Spheroid formation of human keratinocyte: Balancing between cell-substrate and cell-cell interaction %U https://doi.org/10.3233/CH-209217 2 %X Conclusively, the decreased cell- substrate adhesion was the main driven force in the spheroid formation. This finding might serve as a design criterion for biomaterials facilitating the formation of epithelial spheroids. %0 journal article %@ 1386-0291 %A Tung, W., Zou, J., Sun, X., Wang, W., Gould, O., Kratz, K., Ma, N., Lendlein, A. %D 2020 %J Clinical Hemorheology and Microcirculation %N 1 %P 53-66 %R doi:10.3233/CH-199235 %T Coaxial electrospinning of PEEU/gelatin to fiber meshes with enhanced mesenchymal stem cell attachment and proliferation %U https://doi.org/10.3233/CH-199235 1 %X Microfibers with a core-shell structure can be produced by co-axial electrospinning, allowing for the functionalization of the outer layer with bioactive molecules. In this study, a thermoplastic, degradable polyesteretherurethane (PEEU), consisting of poly(p-dioxanone) (PPDO) and poly(ɛ-caprolactone) (PCL) segments with different PPDO to PCL weight ratios, were processed into fiber meshes by co-axial electrospinning with gelatin. The prepared PEEU fibers have a diameter of 1.3±0.5 μm and an elastic modulus of around 5.1±1.0 MPa as measured by tensile testing in a dry state at 37°C, while the PEEU/Gelatin core-shell fibers with a gelatin content of 12±6 wt% and a diameter of 1.5±0.5 μm possess an elastic modulus of 15.0±1.1 MPa in a dry state at 37 °C but as low as 0.7±0.7 MPa when hydrated at 37 °C. Co-axial electrospinning allowed for the homogeneous distribution of the gelatin shell along the whole microfiber. Gelatin with conjugated Fluorescein (FITC) remained stable on the PEEU fibers after 7 days incubation in Phosphate-buffered saline (PBS) at 37 °C. The gelatin coating on PEEU fibers lead to enhanced human adipose tissue derived mesenchymal stem cell (hADSC) attachment and a proliferation rate 81.7±34.1 % higher in cell number in PEEU50/Gelatin fibers after 7 days of cell culture when compared to PEEU fibers without coating. In this work, we demonstrate that water-soluble gelatin can be incorporated as the outer shell of a polymer fiber via molecular entanglement, with a sustained presence and role in enhancing stem cell attachment and proliferation. %0 journal article %@ 1386-0291 %A Schulz, C., Krüger-Genge, A., Jung, F., Lendlein, A. %D 2020 %J Clinical Hemorheology and Microcirculation %N 2 %P 201-217 %R doi:10.3233/CH-190775 %T Aptamer supported in vitro endothelialization of poly(ether imide) films %U https://doi.org/10.3233/CH-190775 2 %X Implantation of synthetic small-diameter vascular bypass grafts is often associated with an increased risk of failure, due to thrombotic events or late intimal hyperplasia. As one of the causes an insufficient hemocompatibility of the artificial surface is discussed. Endothelialization of synthetic grafts is reported to be a promising strategy for creating a self-renewing and regulative anti-thrombotic graft surface. However, the establishment of a shear resistant cell monolayer is still challenging. In our study, cyto- and immuno-compatible poly(ether imide) (PEI) films were explored as potential biomaterial for cardiovascular applications. Recently, we reported that the initial adherence of primary human umbilical vein endothelial cells (HUVEC) was delayed on PEI-films and about 9 days were needed to establish a confluent and almost shear resistant HUVEC monolayer. To accelerate the initial adherence of HUVEC, the PEI-film surface was functionalized with an aptamer-cRGD peptide based endothelialization supporting system. With this functionalization the initial adherence as well as the shear resistance of HUVEC on PEI-films was considerable improved compared to the unmodified polymer surface. The in vitro results confirm the general applicability of aptamers for an efficient functionalization of substrate surfaces. %0 journal article %@ 1386-0291 %A Rickert, D., Steinhart, H., Lendlein, A. %D 2020 %J Clinical Hemorheology and Microcirculation %N 2 %P 179-189 %R doi:10.3233/CH-209212 %T Functional requirements for polymeric implant materials in head and neck surgery %U https://doi.org/10.3233/CH-209212 2 %X A sufficient stability of the polymeric material is a requirement for the pharyngeal reconstruction with implant materials. %0 journal article %@ 2059-8521 %A Liu, Y., Gould, O., Kratz, K., Lendlein, A. %D 2020 %J MRS Advances %N 46 - 47 %P 2391-2399 %R doi:10.1557/adv.2020.276 %T Shape-Memory Actuation of Individual Micro-/Nanofibers %U https://doi.org/10.1557/adv.2020.276 46 - 47 %X Advances in the fabrication and characterization of polymeric nanomaterials has greatly advanced the miniaturization of soft actuators, creating materials capable of replicating the functional physical behavior previously limited to the macroscale. Here, we demonstrate how a reversible shape-memory polymer actuation can be generated in a single micro/nano object, where the shape change during actuation of an individual fiber can be dictated by programming using an AFM-based method. Electrospinning was used to prepare poly(ε-caprolactone) micro-/nanofibers, which were fixed and crosslinked on a structured silicon wafer. The programming as well as the observation of recovery and reversible displacement of the fiber were performed by vertical three point bending, using an AFM testing platform introduced here. A plateau tip was utilized to improve the stability of the fiber contact and working distance, enabling larger deformations and greater rbSMPA performance. Values for the reversible elongation of εrev = 3.4 ± 0.1% and 10.5 ± 0.1% were obtained for a single micro (d = 1.0 ± 0.2 μm) and nanofiber (d = 300 ± 100 nm) in cyclic testing between the temperatures 10 and 60 °C. The reversible actuation of the nanofiber was successfully characterized for 10 cycles. The demonstration and characterization of individual shape-memory nano and microfiber actuators represents an important step in the creation of miniaturized robotic devices capable of performing complex physical functions at the length scale of cells and structural component of the extracellular matrix. %0 conference lecture %@ %A Roku, A., Curio, J., Abulgasim, K., Kasner, M., Lauten, A., Lendlein, A., Landmesser, U., Reinthaler, M. %D 2020 %J 39. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheoligie (DGKMH) %T Intracardiac Echocardiography in Edge-to-Edge Transcatheter Tricuspid Valve Repair (EETVr) %U %X %0 conference poster %@ %A Deng, Z., Wang, W., Xu, X., Na, N., Lendlein, A. %D 2020 %J Virtual MRS Spring/Fall Meeting 2020 %T Modulation of Mesenchymal Stem Cell Migration using Programmable Polymer Sheet Actuators %U %X %0 journal article %@ 1525-7797 %A You, Z., Behl, M., Grage, S., Bürck, J., Zhao, Q., Ulrich, A., Lendlein, A. %D 2020 %J Biomacromolecules %N 2 %P 680-687 %R doi:10.1021/acs.biomac.9b01390 %T Shape-Memory Effect by Sequential Coupling of Functions over Different Length Scales in an Architectured Hydrogel %U https://doi.org/10.1021/acs.biomac.9b01390 2 %X The integration of functions in materials in order to gain macroscopic effects in response to environmental changes is an ongoing challenge in material science. Here, functions on different hierarchical levels are sequentially linked to translate a pH-triggered conformational transition from the molecular to the macroscopic level to induce directed movements in hydrogels. When the pH is increased, lysine-rich peptide molecules change their conformation into a β-hairpin structure because of the reduced electrostatic repulsion among the deprotonated amino groups. Coupled to this conformation change is the capability of the β-hairpin motifs to subsequently assemble into aggregates acting as reversible cross-links, which are used as controlling units to fix a temporary macroscopic shape. A structural function implemented into the hydrogel by a microporous architecture-enabled nondisruptive deformation upon compression by buckling of pore walls and their elastic recovery. Coupled to this structural function is the capability of the porous material to enhance the diffusion of ions into the hydrogel and to keep the dimension of the macroscopic systems almost constant when the additional cross-links are formed or cleaved as it limits the dimensional change of the pore walls. Covalent cross-linking of the hydrogel into a polymer network acted as gear shift to ensure translation of the function on the molecular level to the macroscopic dimension. In this way, the information of a directed shape-shift can be programmed into the material by mechanical deformation and pH-dependent formation of temporary net points. The information could be read out by lowering the pH. The peptides reverted back into their original random coil conformation and the porous polymer network could recover from the previously applied elastic deformation. The level of multifunctionality of the hydrogels can be increased by implementation of additional orthogonal functions such as antimicrobicity by proper selection of multifunctional peptides, which could enable sophisticated biomedical devices. %0 conference poster %@ %A Sun, X., Tung, W., Zou, J., Liu, Y., Wang, W., Kratz, K., Ma, N., Lendlein, A. %D 2020 %J Virtual MRS Spring/Fall Meeting %T PEEU fiber mesh elasticity and its regulatory effects on human endothelial cells %U %X %0 journal article %@ 1386-0291 %A Lee, S., Ganesan, R., Krüger-Genge, A., Kratz, K., Franke, R., Lendlein, A., Jung, F. %D 2020 %J Clinical Hemorheology and Microcirculation %N 1 %P 85-98 %R doi:10.3233/CH-190736 %T Substrate-enzyme affinity-based surface modification strategy for endothelial cell-specific binding under shear stress %U https://doi.org/10.3233/CH-190736 1 %X Establishing an endothelial cell (EC) monolayer on top of the blood contacting surface of grafts is considered to be a promising approach for creating a hemocompatible surface. Here we utilized the high affinity interactions between the EC plasma membrane expressed enzyme called endothelin converting enzyme-1 (ECE-1) and its corresponding substrate big Endothelin-1 (bigET-1) to engineer an EC-specific binding surface. Since enzymatic cleavage of substrates require physical interaction between the enzyme and its corresponding substrate, it was hypothesized that a surface with chemically immobilized synthetic bigET-1 will preferentially attract ECs over other types of cells found in vascular system such as vascular smooth muscle cells (VSMCs). First, the expression of ECE-1 was significantly higher in ECs, and ECs processed synthetic bigET-1 to produce ET-1 in a cell number-dependent manner. Such interaction between ECs and synthetic bigET-1 was also detectible in blood. Next, vinyl-terminated self-assembled monolayers (SAMs) were established, oxidized and activated on a glass substrate as a model to immobilize synthetic bigET-1 via amide bonds. The ECs cultured on the synthetic bigET-1-immobilized surface processed larger amount of synthetic bigET-1 to produce ET-1 compared to VSMCs (102.9±5.13 vs. 9.75±0.74 pg/ml). The number of ECs bound to the synthetic bigET-1-immobilized surface during 1 h of shearing (5dyne/cm2) was approximately 3-fold higher than that of VSMCs (46.25±12.61 vs. 15.25±3.69 cells/100×HPF). EC-specific binding of synthetic bigET-1-immobilized surface over a surface modified with collagen, a common substance for cell adhesion, was also observed. The present study demonstrated that using the substrate-enzyme affinity (SEA) of cell type-specific enzyme and its corresponding substrate can be an effective method to engineer a surface preferentially binds specific type of cells. This novel strategy might open a new route toward rapid endothelialization under dynamic conditions supporting the long-term patency of cardiovascular implants. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2020 %J American Chemical Society Fall 2020 Virtual Meeting & EXPO %T Programming biomaterials - Design and Strategies %U %X %0 journal article %@ 2059-8521 %A Luetzow, K., Weigel, T., Lendlein, A. %D 2020 %J MRS Advances %N 14 - 15 %P 785-795 %R doi:10.1557/adv.2019.422 %T Solvent-based Fabrication Method for Magnetic, Shape-Memory Nanocomposite Foams %U https://doi.org/10.1557/adv.2019.422 14 - 15 %X This paper presents shape-memory foams that can be temporarily fixed in their compressed state and be expanded on demand. Highly porous, nanocomposite foams were prepared from a solution of polyeiherureihane with suspended nanoparticles (mean aggregate size 90 nm) which have an iron(III) oxide core with a silica shell. The polymer solution with suspended nanoparticles was cooled down to -20 °C in a two-stage process, which was followed by freeze-diying. The average pore size increases with decreasing concentration of nanoparticles from 158 μm to 230 jum while the foam porosity remained constant. After fixation of a temporaiy form of the nanocomposite foams, shape recovery can be triggered either by heat or by exposure to an alternating magnetic field. Compressed foams showed a recovery rate of up to 76 ± 4% in a thermochamber at 80 °C, and a slightly lower recovery rate of up to 65 ± 4% in a magnetic field. %0 journal article %@ 1386-0291 %A Curio, J., Abulgasim, K., Kasner, M., Rroku, A., Lauten, A., Lendlein, A., Landmesser, U., Reinthaler, M. %D 2020 %J Clinical Hemorheology and Microcirculation %N 2 %P 199-210 %R doi:10.3233/CH-209211 %T Intracardiac echocardiography to enable successful edge-to-edge transcatheter tricuspid valve repair in patients with insufficient TEE quality %U https://doi.org/10.3233/CH-209211 2 %X BACKGROUND:Transesophageal echocardiography (TEE) as a guiding tool for edge-to-edge transcatheter tricuspid valve repair (EETVr) using MitraClip (Abbott Vascular, Santa Clara, USA) may not offer sufficient image quality in a significant proportion of patients. OBJECTIVES:Intracardiac echocardiography (ICE) as additional guiding tool in EETVr with the MitraClip device. METHODS:Appropriate angulations of the ICE catheter to visualize each commissure of the tricuspid valve were established in 3D printed heart models. In a single tertiary-care center ICE was used to support EETVr as additional guidance when TEE image quality was insufficient. Procedural safety and outcomes up to 30-days were compared between ICE/TEE and TEE only guided patients. RESULTS:In 6 of 11 patients (54.5%) undergoing EETVr with MitraClip TEE alone was unsatisfactory, necessitating additional ICE guidance. In 4 of these 6 patients ICE enabled a successful completion of the procedure. The steering maneuvers identified in the 3D models were well applicable in all patients, providing examples for potential future ICE implementation in EETVr. Under both TEE alone (n = 5) and ICE (n = 6) guidance the rate of procedural complications was 0%. According to vena contracta values at discharge significant TR reduction was achievable in the treated cohort (p = 0.011). At 30-days follow-up one patient (ICE guided) died following global heart failure, not associated with the procedure itself. CONCLUSIONS:ICE guidance may offer an additional tool to guide EETVr with the MitraClip device in patients with poor TEE quality, as it enables successful results without impairing procedural safety. %0 conference lecture %@ %A Behl, M., Balk, M., Mansfeld, U., Lendlein, A. %D 2020 %J Virtual MRS Spring/Fall Meeting 2020 %T Robot-Assisted Synthesis of Alternating and Random Multiblock Copolymers Based on Oligo(ε-caprolactone)/Oligotetrahydrofurane and Their Phase Morphology %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2019 %J Purdue University; Department of Industrial and Physical Pharmacy %T Multifunctional; degradable polymers for health technologies %U %X %0 conference poster %@ %A Zou, J., Wang, W., Sun, X., Tung, W., Ma, N., Lendlein, A. %D 2019 %J MRS Fall Meeting 2019 %T AFM Assessment of the Mechanical Properties of Stem Cells During Differentiation %U %X %0 conference poster %@ %A Rickert, D., Lendlein, A. %D 2019 %J MRS Fall Meeting 2019 %T First Results of the Mucosa Reconstruction in an Animal Model with a Polymeric Implant Material %U %X %0 conference poster %@ %A Machatschek, R., Schulz, B., Lendlein, A. %D 2019 %J AFPM - Advanced Functional Polymers for Medicine 2019 %T Towards a prediction of polymer degradation with Langmuir monolayer degradation experiments %U %X %0 conference poster %@ %A Pang, J., Wischke, C., Lendlein, A. %D 2019 %J MRS Fall Meeting 2019 %T Preparation and Degradation Analysis of Multifunctional 3D-architectured Gelatin-based Hydrogels %U %X %0 conference poster %@ %A Xu, X., Wang, W., Nie, Y., Kratz, K., Ma, N., Lendlein, A. %D 2019 %J MRS Fall Meeting 2019 %T Fine-tuning of Rat Mesenchymal Stem Cell Senescence via Microtopography of Polymeric Substrates %U %X %0 conference poster %@ %A Wischke, C., Kersting, M., Welle, A., Lysyakova, L., Braune, S., Kratz, K., Franzreb, M., Lendlein, A. %D 2019 %J MRS Fall Meeting 2019 %T Thin hydrogel coatings by enzyme-catalyzed mechanism %U %X %0 conference poster %@ %A Nie, Y., Deng, Z., Wang, W., Vijaya Bhaskar, T., Ma, N., Lendlein, A. %D 2019 %J MRS Fall Meeting 2019 %T Polydopamine-mediated Surface Modification Promotes the Adhesion and Proliferation of HumanInduced Pluripotent Stem Cell %U %X %0 conference poster %@ %A Vijaya Bhaskar, T., Machatschek, R., Schulz, B., Ma, N., Lendlein, A. %D 2019 %J MRS Fall Meeting 2019 %T Biomimetic Fibronectin Fibrillogenesis at Air/Water interface %U %X %0 conference poster %@ %A Tarazona, N., Machatschek, R., Schulz, B., Lendlein, A. %D 2019 %J MRS Fall Meeting 2019 %T Real-time Characterization of the Degradation and Chemi-crystallization Phenomenon in NaturalbasedPolymers at the Air-Water Interface: the Story of Bacterial Polyesters %U %X %0 conference poster %@ %A Bäckemo Johansson, D., Heuchel, M., Reinthaler, M., Kratz, K., Lendlein, A. %D 2019 %J MRS Fall Meeting 2019 %T Computational Modelling of Electrical Discharge Machining (EDM) for Tuning Surface Roughness andCurvature %U %X The application of such a computational model may be useful in predicting how a surface is deformed, and what input parameters to use to create a surface with certain desired surface function. Future improvements of the model may include volumetric changes, surface charge and heat transfer. %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2019 %J Berufs- und Orientierungstag; Vicco-von-Bülow Gymnasium %T Kunststoffe sind mehr als nur Mikroplastik - Verwendung in der Medizin %U %X %0 journal article %@ 1386-0291 %A Zou, J., Wang, W., Kratz, K., Xu, X., Nie, Y., Ma, N., Lendlein, A. %D 2019 %J Clinical Hemorheology and Microcirculation %N 4 %P 573-583 %R doi:10.3233/CH-189322 %T Evaluation of human mesenchymal stem cell senescence, differentiation and secretion behavior cultured on polycarbonate cell culture inserts %U https://doi.org/10.3233/CH-189322 4 %X Polycarbonate (PC) substrate is well suited for culturing human mesenchymal stem cells (MSCs) with high proliferation rate, low cell apoptosis rate and negligible cytotoxic effects. However, little is known about the influence of PC on MSC activity including senescence, differentiation and secretion. In this study, the PC cell culture insert was applied for human MSC culture and was compared with polystyrene (PS) and standard tissue culture plate (TCP). The results showed that MSCs were able to adhere on PC surface, exhibiting a spindle-shaped morphology. The size and distribution of focal adhesions of MSCs were similar on PC and TCP. The senescence level of MSCs on PC was comparable to that on TCP, but was significantly lower than that on PS. MSCs on PC were capable of self-renewal and differentiation into multiple cell lineages, including osteogenic and adipogenic lineages. MSCs cultured on PC secreted a higher level inflammatory cytokines and pro-angiogenic factors including FGF2 and VEGF. Conclusively, PC represents a promising cell culture material for human MSCs. %0 journal article %@ 1386-0291 %A Nie, Y., Wang, W., Xu, X., Zou, J., Bhuvanesh, T., Schulz, B., Ma, N., Lendlein, A. %D 2019 %J Clinical Hemorheology and Microcirculation %N 4 %P 531-542 %R doi:10.3233/CH-189318 %T Enhancement of human induced pluripotent stem cells adhesion through multilayer laminin coating %U https://doi.org/10.3233/CH-189318 4 %X Bioengineered cell substrates are a highly promising tool to govern the differentiation of stem cells in vitro and to modulate the cellular behavior in vivo. While this technology works fine for adult stem cells, the cultivation of human induced pluripotent stem cells (hiPSCs) is challenging as these cells typically show poor attachment on the bioengineered substrates, which among other effects causes substantial cell death. Thus, very limited types of surfaces have been demonstrated suitable for hiPSC cultures. The multilayer coating approach that renders the surface with diverse chemical compositions, architectures, and functions can be used to improve the adhesion of hiPSCs on the bioengineered substrates. We hypothesized that a multilayer formation based on the attraction of molecules with opposite charges could functionalize the polystyrene (PS) substrates to improve the adhesion of hiPSCs. Polymeric substrates were stepwise coated, first with dopamine to form a polydopamine (PDA) layer, second with polylysine and last with Laminin-521. The multilayer formation resulted in the variation of hydrophilicity and chemical functionality of the surfaces. Hydrophilicity was detected using captive bubble method and the amount of primary and secondary amines on the surface was quantified by fluorescent staining. The PDA layer effectively immobilized the upper layers and thereby improved the attachment of hiPSCs. Cell adhesion was enhanced on the surfaces coated with multilayers, as compared to those without PDA and/or polylysine. Moreover, hiPSCs spread well over this multilayer laminin substrate. These cells maintained their proliferation capacity and differentiation potential. The multilayer coating strategy is a promising attempt for engineering polymer-based substrates for the cultivation of hiPSCs and of interest for expanding the application scope of hiPSCs. %0 journal article %@ 1022-1336 %A Machatschek, R., Schulz, B., Lendlein, A. %D 2019 %J Macromolecular Rapid Communications %N 1 %P 1800611 %R doi:10.1002/marc.201800611 %T Langmuir Monolayers as Tools to Study Biodegradable Polymer Implant Materials %U https://doi.org/10.1002/marc.201800611 1 %X Langmuir monolayers provide a fast and elegant route to analyze the degradation behavior of biodegradable polymer materials. In contrast to bulk materials, diffusive transport of reactants and reaction products in the (partially degraded) material can be neglected at the air–water interface, allowing for the study of molecular degradation kinetics in experiments taking less than a day and in some cases just a few minutes, in contrast to experiments with bulk materials that can take years. Several aspects of the biodegradation behavior of polymer materials, such as the interaction with biomolecules and degradation products, are directly observable. Expanding the technique with surface‐sensitive instrumental techniques enables evaluating the evolution of the morphology, chemical composition, and the mechanical properties of the degrading material in situ. The potential of the Langmuir monolayer degradation technique as a predictive tool for implant degradation when combined with computational methods is outlined, and related open questions and strategies to overcome these challenges are pointed out. %0 journal article %@ 0378-5173 %A Friess, F., Roch, T., Seifert, B., Lendlein, A., Wischke, C. %D 2019 %J International Journal of Pharmaceutics %P 118461 %R doi:10.1016/j.ijpharm.2019.118461 %T Phagocytosis of spherical and ellipsoidal micronetwork colloids from crosslinked poly(ε-caprolactone) %U https://doi.org/10.1016/j.ijpharm.2019.118461 %X The effect of non-spherical particle shapes on cellular uptake has been reported as a general design parameter to control cellular recognition of particulate drug carriers. Beside shape, also size and cell-particle ratio should mutually effect phagocytosis. Here, the capability to control cellular uptake of poly(ɛ-caprolactone) (PCL) based polymer micronetwork colloids (MNC), a carrier system that can be transferred to various shapes, is explored in vitro at test conditions allowing multiple cell-particle contacts. PCL-based MNC were synthesized as spheres with a diameter of ∼6, ∼10, and 13 µm, loaded with a fluorescent dye by a specific technique of swelling, re-dispersion and drying, and transferred into different ellipsoidal shapes by a phantom stretching method. The boundaries of MNC deformability to prolate ellipsoid target shapes were systematically analyzed and found to be at an aspect ratio AR of ∼4 as obtained by a phantom elongation εph of ∼150%. Uptake studies with a murine macrophages cell line showed shape dependency of phagocytosis for selected conditions when varying particle sizes (∼6 and 10 μm),and shapes (εph: 0, 75 or 150%), cell-particle ratios (1:1, 1:2, 1:10, 1:50), and time points (1–24 h). For larger-sized MNC, there was no significant shape effect on phagocytosis as these particles may associate with more than one cell, thus increasing the possibility of phagocytosis by any of these cells. Accordingly, controlling shape effects on phagocytosis for carriers made from degradable polymers relevant for medical applications requires considering further parameters besides shape, such as kinetic aspects of the exposure and uptake by cells. %0 journal article %@ 1386-0291 %A Kuhnla, A., Reinthaler, M., Braune, S., Maier, A., Pindur, G., Lendlein, A., Jung, F. %D 2019 %J Clinical Hemorheology and Microcirculation %N 4 %P 425-435 %R doi:10.3233/CH-199006 %T Spontaneous and induced platelet aggregation in apparently healthy subjects in relation to age %U https://doi.org/10.3233/CH-199006 4 %X Thrombotic disorders remain the leading cause of mortality and morbidity, despite the fact that anti-platelet therapies and vascular implants are successfully used today. As life expectancy is increasing in western societies, the specific knowledge about processes leading to thrombosis in elderly is essential for an adequate therapeutic management of platelet dysfunction and for tailoring blood contacting implants. This study addresses the limited available data on platelet function in apparently healthy subjects in relation to age, particularly in view of subjects of old age (80–98 years). Apparently healthy subjects between 20 and 98 years were included in this study. Platelet function was assessed by light transmission aggregometry and comprised experiments on spontaneous as well as ristocetin-, ADP- and collagen-induced platelet aggregation. The data of this study revealed a non-linear increase in the maximum spontaneous platelet aggregation (from 3.3% ±3.3% to 10.9% ±5.9%). The maximum induced aggregation decreased with age for ristocetin (from 85.8% ±7.2% to 75.0% ±7.8%), ADP (from 88.5% ±4.6% to 64.8% ±7.3%) and collagen (from 89.5% ±3.0% to 64.0% ±4.0%) in a non-linear manner (linear regression analysis). These observations indicate that during aging, circulating platelets become increasingly activated but lose their full aggregatory potential, a phenomenon that was earlier termed “platelet exhaustion”. In this study we extended the limited existing data for spontaneous and induced platelet aggregation of apparently healthy donors above the age of 75 years. The presented data indicate that the extrapolation of data from a middle age group does not necessarily predict platelet function in apparently healthy subjects of old age. It emphasizes the need for respective studies to improve our understanding of thrombotic processes in elderly humans. %0 journal article %@ 0036-8075 %A Yuan, J., Neri, W., Zakri, C., Merzeau, P., Kratz, K., Lendlein, A., Poulin, P. %D 2019 %J Science %N 6449 %P 155-158 %R doi:10.1126/science.aaw3722 %T Shape memory nanocomposite fibers for untethered high-energy microengines %U https://doi.org/10.1126/science.aaw3722 6449 %X Classic rotating engines are powerful and broadly used but are of complex design and difficult to miniaturize. It has long remained challenging to make large-stroke, high-speed, high-energy microengines that are simple and robust. We show that torsionally stiffened shape memory nanocomposite fibers can be transformed upon insertion of twist to store and provide fast and high-energy rotations. The twisted shape memory nanocomposite fibers combine high torque with large angles of rotation, delivering a gravimetric work capacity that is 60 times higher than that of natural skeletal muscles. The temperature that triggers fiber rotation can be tuned. This temperature memory effect provides an additional advantage over conventional engines by allowing for the tunability of the operation temperature and a stepwise release of stored energy. %0 journal article %@ 1386-0291 %A Zou, J., Wang, W., Nie, Y., Xu, X., Ma, N., Lendlein, A. %D 2019 %J Clinical Hemorheology and Microcirculation %N 1 %P 237-247 %R doi:10.3233/CH-199205 %T Microscale roughness regulates laminin-5 secretion of bone marrow mesenchymal stem cells %U https://doi.org/10.3233/CH-199205 1 %X Laminin-5 (Ln-5), an important ECM protein, plays a critical role in regulating the growth and differentiation of mesodermal tissues, including bone. Ln-5 can be secreted by the mesenchymal stem cells (MSCs), and Ln-5 promotes MSCs osteogenic differentiation. It has been demonstrated that substrate surface topography could regulate MSC secretion and differentiation. A better understanding of the mechanism of Ln-5 and surface roughness regulating MSC osteogenic differentiation, which would provide a guide way for the surface topography design and coating of orthopedic implants and cell culture substrates. However, few studies have investigated the relationship between surface roughness and the secretion of Ln-5 in the MSC osteogenic differentiation. Whether substrate surface topography regulates MSC differentiation via regulating Ln-5 secretion and how surface topography contributes to the secretion of Ln-5 are still not known. In this study, the influence of microscale roughness at different levels (R0, R1 and R2) on the secretion of Ln-5 of human bone marrow MSCs (hBMSCs) and subsequent osteogenic differentiation were examined. hBMSCs spreading, distribution and morphology were largely affected by different roughness levels. A significantly higher level of Ln-5 secretion was detected on R2, which correlated to the local cell density regulated by the rough surface. Ln-5 binding integrins (α2 and α3) were strongly activated on R2. In addition, the results from hBMSCs on R0 inserts with different cell densities further confirmed that local cell density regulated Ln-5 secretion and cell surface integrin activation. And the mineralization level of MSCs on R2 was remarkably higher than that on R0 and R1. These results suggested that hBMSC osteogenic differentiation level on R2 roughness was enhanced via increased Ln-5 secretion that was attributed to rough surface regulated local cell density. Thus, the microroughness could serve as effective topographical stimulus in cell culture devices and bone implant materials. %0 conference lecture %@ %A Lau, S., Rangarajan, R., Krüger-Genge, A., Braune, S., Küpper, J., Lendlein, A., Jung, F. %D 2019 %J 38. Jahrestagung der Deutschen Gesellschaft für klinische Mikrozirkulation und Hämorheologie %T Age-related morphology and function of human arterial endothelial cells %U %X The world health organization defines ageing as a natural, inevitable and multifactorial process that occurs at genetic, molecular, cellular, organ and system levels. Among the biological structures that are affected by ageing, endothelial cells are of utmost importance due to their role in regulating blood flow and vascular hemostasis. In vitro cultivation of endothelial cells over several passages leads to morphological and functional changes which has been described as replicative senescence. However, it is unclear whether these changes in vitro reflect human cellular ageing in vivo. A recent study analyzed freshly isolated endothelial cells, which were removed from vessels via J-wires, and showed that the expression of senescence markers p53, p16 and p21 was increased in endothelial cells from aged donors [1]. Moreover, it was observed that tumors in the later stage of life (>80 years) grow slower suggesting that cell growth is decelerated with increasing age. However, clear evidence for this is missing. %0 conference lecture %@ %A Braune, S., Xourida, M., Maier, A., Reinthaler, M., Kratz, K., Latour, R., Lendlein, A., Jung, F. %D 2019 %J 38. Jahrestagung der Deutschen Gesellschaft für klinische Mikrozirkulation und Hämorheologie %T Translocation and release of Von Willebrand factor in the adherent platelet %U %X The adsorption of proteins from blood plasma, molecules secreted by blood cells - such as the activated platelet - participates in orchestrating the overall hemocompatibility of cardiovascular implants. Here, we studied the translocation and secretion of von Willebrand factor (VWF) from human platelets on implant materials using three-dimensional super resolution microscopy in order to explore how local secretion processes can influence thrombotic processes. We hypothesize that beyond the secretion of VWF from the platelet granula, also not secreted VWF might be available on blood contacting implant surfaces after the full activation of the adherent platelet. %0 journal article %@ 2192-2659 %A Braune, S., Latour, R., Reinthaler, M., Landmesser, U., Lendlein, A., Jung, F. %D 2019 %J Advanced Healthcare Materials %N 21 %P 1900527 %R doi:10.1002/adhm.201900527 %T In Vitro Thrombogenicity Testing of Biomaterials %U https://doi.org/10.1002/adhm.201900527 21 %X The short‐ and long‐term thrombogenicity of implant materials is still unpredictable, which is a significant challenge for the treatment of cardiovascular diseases. A knowledge‐based approach for implementing biofunctions in materials requires a detailed understanding of the medical device in the biological system. In particular, the interplay between material and blood components/cells as well as standardized and commonly acknowledged in vitro test methods allowing a reproducible categorization of the material thrombogenicity requires further attention. Here, the status of in vitro thrombogenicity testing methods for biomaterials is reviewed, particularly taking in view the preparation of test materials and references, the selection and characterization of donors and blood samples, the prerequisites for reproducible approaches and applied test systems. Recent joint approaches in finding common standards for a reproducible testing are summarized and perspectives for a more disease oriented in vitro thrombogenicity testing are discussed. %0 conference lecture %@ %A Tung, W., Wang, W., Kratz, K., Ma, N., Lendlein, A. %D 2019 %J 38. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheoligie (DGKMH) %T Determining the mechanic properties of electrospun Polyesteretherurethane (PEEU) microfibers using AFM %U %X %0 journal article %@ 2059-8521 %A Folikumah, M., Neffe, A., Behl, M., Lendlein, A. %D 2019 %J MRS Advances %N 46 - 47 %P 2515-2525 %R doi:10.1557/adv.2019.308 %T Thiol Michael-Type Reactions of Optically Active Mercapto-Acids in Aqueous Medium %U https://doi.org/10.1557/adv.2019.308 46 - 47 %X In model reactions were investigated the kinetics, the specificity and influence of stereochemistry of this reaction. We could show that only reactions involving SH-Leu yielded the expected thiol-Michael product. The inability of SH-Phe to react was attributed to the steric hindrance of the bulky phenyl group. In aqueous media, successful reaction using SH-Leu is thought to proceed via the sodium salt formed in-situ by the addition of NaOH solution, which was intented to aid the solubility of the mercapto-acid in water. Fast reaction rates and complete acrylate/maleimide conversion were only realized at pH 7.2 or higher suggesting the possible use of SH-Leu under physiological conditions for thiol Michael-type reactions. This method of in-situ formed alkali salts could be used as a fast approach to screen mercapto-acids for thio Michael-type reactions without the synthesis of their corresponding esters. %0 journal article %@ 1386-0291 %A Tung, W., Wang, W., Liu, Y., Gould, O., Kratz, K., Ma, N., Lendlein, A. %D 2019 %J Clinical Hemorheology and Microcirculation %N 1 %P 229-236 %R doi:10.3233/CH-199201 %T Mechanical characterization of electrospun polyesteretherurethane (PEEU) meshes by atomic force microscopy %U https://doi.org/10.3233/CH-199201 1 %X The mechanical properties of electrospun fiber meshes typically are measured by tensile testing at the macro-scale without precisely addressing the spatial scale of living cells and their submicron architecture. Atomic force microscopy (AFM) enables the examination of the nano- and micro-mechanical properties of the fibers with potential to correlate the structural mechanical properties across length scales with composition and functional behavior. In this study, a polyesteretherurethane (PEEU) polymer containing poly(p-dioxanone) (PPDO) and poly(ɛ-caprolactone) (PCL) segments was electrospun into fiber meshes or suspended single fibers. We employed AFM three point bending testing and AFM force mapping to measure the elastic modulus and stiffness of individual micro/nanofibers and the fiber mesh. The local stiffness of the fiber mesh including the randomized, intersecting structure was also examined for each individual fiber. Force mapping results with a set point of 50 nN demonstrated the dependence of the elasticity of a single fiber on the fiber mesh architecture. The non-homogeneous stiffness along the same fiber was attributed to the intersecting structure of the supporting mesh morphology. The same fiber measured at a point with and without axial fiber support showed a remarkable difference in stiffness, ranging from 0.2 to 10 nN/nm respectively. For the region, where supporting fibers densely intersected, the stiffness was found to be considerably higher. In the region where the degrees of freedom of the fibers was not restricted, allowing greater displacement, the stiffness were observed to be lower. This study elucidates the relationship between architecture and the mechanical properties of a micro/nanofiber mesh. By providing a greater understanding of the role of spatial arrangement and organization on the surface mechanical properties of such materials, we hope to provide insight into the design of microenvironments capable of regulating cell functionality. %0 journal article %@ 1386-0291 %A Sun, X., Tung, W., Wang, W., Xu, X., Zou, J., Gould, O., Kratz, K., Ma, N., Lendlein, A. %D 2019 %J Clinical Hemorheology and Microcirculation %N 1 %P 219-228 %R doi:10.3233/CH-199206 %T The effect of stiffness variation of electrospun fiber meshes of multiblock copolymers on the osteogenic differentiation of human mesenchymal stem cells %U https://doi.org/10.3233/CH-199206 1 %X Electrospinning has attracted significant attention as a method to produce cell culture substrates whose fibrous structure mimics the native extracellular matrix (ECM). In this study, the influence of E-modulus of fibrous substrates on the lineage commitment of human adipose-derived stem cells (hADSCs) was studied using fiber meshes prepared via the electrospinning of a polyetheresterurethane (PEEU) consisting of poly(ρ-dioxanone) (PPDO) and poly(ɛ-caprolactone) (PCL) segments. The PPDO: PCL weight ratio was varied from 40:60 to 70:30 to adjust the physiochemical properties of the PEEU fibers. The cells attached on stiffer PEEU70 (PPDO:PCL,= 70:30) fiber meshes displayed an elongated morphology compared to those cultured on softer fibers. The nuclear aspect ratio (width vs. length of a nucleus) of hADSCs cultured on softer PEEU40 (PPDO:PCL = 40:60) fibers was lower than on stiffer fibers. The osteogenic differentiation of hADSCs was enhanced by culturing on stiffer fibers. Compared to PEEU40, a 73% increase of osteocalcin expression and a 34% enhancement of alkaline phosphatase (ALP) activity was observed in cells on PEEU70. These results demonstrated that the differentiation commitment of stem cells could be regulated via tailoring the mechanical properties of electrospun fibers. %0 journal article %@ 2059-8521 %A Friess, F., Wischke, C., Lendlein, A. %D 2019 %J MRS Advances %N 59 - 60 %P 3199-3206 %R doi:10.1557/adv.2019.392 %T Microscopic analysis of shape-shiftable oligo (ε-caprolactone) — based particles %U https://doi.org/10.1557/adv.2019.392 59 - 60 %X Spherical particles are routinely monitored and described by hydrodynamic diameters determined, e.g., by light scattering techniques. Non-spherical particles such as prolate ellipsoids require alternative techniques to characterize particle size as well as particle shape. In this study, oligo(ε-caprolactone) (oCL) based micronetwork (MN) particles with a shape-shifting function based on their shape-memory capability were programmed from spherical to prolate ellipsoidal shape aided by incorporation and stretching in a water-soluble phantom matrix. By applying light microscopy with automated contour detection and aspect ratio analysis, differences in characteristic aspect ratio distributions of non-crosslinked microparticles (MPs) and crosslinked MNs were detected when the degrees of phantom elongation (30-290%) are increased. The thermally induced shape recovery of programmed MNs starts in the body rather than from the tips of ellipsoids, which may be explained based on local differences in micronetwork deformation. By this approach, fascinating intermediate particle shapes with round bodies and two opposite sharp tips can be obtained, which could be of interest, e.g., in valves or other technical devices, in which the tips allow to temporarily encage the switchable particle in the desired position. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2019 %J Lecture at Columbia University %T Multifunctional Biomaterials and Devices %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2019 %J Lecture at Georgia Institute of Technology %T Function-Function Relationships in Multifunctional Material Systems %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2019 %J MRS Fall Meeting 2019 %T Function-function relationships in multifunctional soft actuators %U %X %0 conference lecture %@ %A Sun, X., Tung, W., Wang, W., Xu, X., Zou, J., Kratz, K., Ma, N., Lendlein, A. %D 2019 %J 38. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheoligie (DGKMH %T Electrospun fiber meshes of multiblock copolymers differing in elasticity affects osteogenic differentiation of hADSCs %U %X %0 conference lecture %@ %A Tung, W., Zou, J., Wang, W., Kratz, K., Ma, N., Lendlein, A. %D 2019 %J 38. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheoligie (DGKMH %T Coaxial electrospinning of Gelatin/PEEU to fiber meshes with enhanced mesenchymal stem cell attachment and proliferation %U %X %0 conference lecture %@ %A Balk, M., Behl, M., Lendlein, A. %D 2019 %J Polydays 2019 - Polymer Science and Engineering in View of Digitalization %T Hydrogels with quadruple-shape capability %U %X within narrow temperature ranges. %0 conference lecture %@ %A Lendlein, A. %D 2019 %J Institutsvorstellung für Unternehmerverband Brandenburg e.V., Arbeitskreis "Innovative Technologien" %T Willkommen am HZG Campus Teltow - Institut für Biomaterialforschung %U %X %0 conference lecture %@ %A Lendlein, A. %D 2019 %J MRS Spring Meeting 2019 : Symposium "Bioinspired materials - From basic discovery to biomimicry" %T (Multi)functional structured hydrogels inspired by ECM %U %X %0 conference lecture %@ %A Keller, M., Lendlein, A. %D 2019 %J Girls´ und Boys´ Day; Zukunftstag für Mädchen und Jungen 2019 %T HZG in Teltow und Kunststoffe in der Medizin %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2019 %J Vortrag in 13. Klasse der Maxim-Gorki Gesamtschule Kleinmachnow %T Kunststoffe in der Medizin - Nicht nur Mikroplastik %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2019 %J Girls´ und Boys´ - Day; Zukunftstag für Mädchen und Jungen 2019 %T Forschung bei HZG - Polymere in der Medizin %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2019 %J Lecture at the SUTD Digital Manufacturing and Design Centre %T Shape-memory Polymers – from one time shape shifters to soft actuator %U %X are outlined including healthcare technologies and rebotics. %0 conference lecture %@ %A Balk, M., Behl, M., Lendlein, A. %D 2019 %J Arbeitskreis Innovative Technologien; Unternehmerverband Brandenburg e.V. %T Komplexe Bewegungen in Hydrogele %U %X %0 conference poster %@ %A Behl, M., Peng, X., Lützow, K., Lendlein, A. %D 2019 %J Advanced Functional Polymers for Medicine 2019 %T Well-defined Telechelic Oliogodepsipeptides as Precursor Materials for Nanoparticulate Gene Carrier Systems %U %X result in well-defined telechelic oDPs. %0 conference poster %@ %A Xu, X., Wang, W., Ma, N., Lendlein, A. %D 2019 %J 13th International Symposium on Frontiers in Biomedical Polymers %T Edge sharpness of geometric microcavity enhances contractility and osteogenesis of mesenchymal stem cells via ROCK signaling %U %X %0 lecture %@ %A Lendlein, A., Schroeter, M., Schulz, B. %D 2019 %J %T WAHLPFLICHT POLYMERCHEMIE (AWP2) 2019 %U %X %0 conference lecture %@ %A Braune, S., Xourida, M., Maier, A., Reinthaler, M., Kratz, K., Latour, R., Lendlein, A., Jung, F. %D 2019 %J 38. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheoligie (DGKMH) %T Translocation and release of von Willebrand factor in the adherent and activated platelet %U %X %0 conference lecture %@ %A Machatschek, R., Schulz, B., Lendlein, A. %D 2019 %J MRS Fall Meeting %T Monolayer Studies on the Interplay between Cross-Linking and the Degradation Kinetics of Biomaterials %U %X %0 conference lecture %@ %A Machatschek, R., Schulz, B., Lendlein, A. %D 2019 %J Arbeitskreis Innovative Technologien; Unternehmerverband Brandenburg e.V. %T Untersuchung und Vorhersage des Abbaus von Polymeren mit Hilfe von 2D Systemen %U %X %0 conference poster %@ %A Machatschek, R., Schulz, B., Lendlein, A. %D 2019 %J Polydays 2019 - Polymer Science and Engineering in View of Digitalization %T Towards a prediction of polymer degradation with quantitative analysis of Langmuir monolayer degradation experiments %U %X %0 conference poster %@ %A Lützow, K., Weigel, T., Kosmella, H., Behl, M., Lendlein, A. %D 2019 %J Polydays 2019 - Polymer Science and Engineering in View of Digitalization %T Shape Recovery of Polymeric Nanocomposite Foams by Direct and Inductive Heating %U %X %0 conference lecture %@ %A Machatschek, R., Schulz, B., Lendlein, A. %D 2019 %J 16th European Conference on Organized Films (ECOF) %T Langmuir monolayers as tool to predict the degradation of architectured macromolecules %U %X %0 conference lecture %@ %A Ceylan Tuncaboylu, D., Friess, F., Wiscke, C., Lendlein, A. %D 2019 %J International Symposium on SupraBiomoelcular Systems - SUPRABIO 2019 %T On-demand release with a multifunctional implant system %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2019 %J 13th International Symposium on Frontiers in Biomedical Polymers %T Designing multifunctionality in polymers to create effects required in biomedical applications %U %X %0 journal article %@ 2059-8521 %A Balk, M., Behl, M., Lendlein, A. %D 2019 %J MRS Advances %N 21 %P 1193-1205 %R doi:10.1557/adv.2019.202 %T Hydrolytic Degradation of Actuators Based on Copolymer Networks From Oligo(ε-caprolactone) Dimethacrylate and n-Butyl Acrylate %U https://doi.org/10.1557/adv.2019.202 21 %X The alkaline hydrolysis decreased the polymer chain orientation of OCL domains until a random alignment of crystalline domains was obtained. This result was confirmed by cyclic thermomechanical actuation tests. The performance of directed movements decreased almost linearly as function of degradation time resulting in the loss of functionality when the orientation of polymer chains disappeared. Here, actuators were able to provide reversible movements until 91 d when the accelerated bulk degradation procedure using alkaline hydrolysis (pH = 13) was applied. Accordingly, a lifetime of more than one year can be guaranteed under physiological conditions (pH = 7.4) when, e.g., artificial muscles for biomimetic robots as potential application for these kind of shape-memory polymer actuators will be addressed. %0 conference poster %@ %A Folikumah, M., Neffe, A., Behl, M., Lendlein, A. %D 2019 %J Polydays 2019 - Polymer Science and Engineering in View of Digitalization %T Thiol-Michael reactions of optically active mercapto-acids in aqueous medium %U %X %0 conference lecture %@ %A Zou, J., Wang, W., Nie, Y., Xu, X., Ma, N., Lendlein, A. %D 2019 %J 38. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheoligie (DGKMH) %T Promoting osteogenesis of human mesenchymal stem cells via cell density related laminin-5 secretion using microscale roughness %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2019 %J Marie Curie Tag am Marie-Curie-Gymnasium Ludwigsfelde %T Kunststoffe in der Medizin - Neue Entwicklungen %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2019 %J Lecture at Carnegie Mellon University (Department of Biomedical Engineering; Department of Materials Science and Engineering) %T Function-Function Relationships in Multifunctional Material Systems %U %X %0 conference poster %@ %A Zou, J., Wang, W., Xu, X., Sun, X., Deng, Z., Nie, Y., Ma, N., Lendlein, A. %D 2019 %J Polydays 2019 - Polymer Science and Engineering in View of Digitalization %T Microroughness of polycarbonate surface promotes osteogenesis of stem cells via regulating cell density related laminin-5 secretion %U %X %0 conference poster %@ %A Sun, X., Tung, W., Zou, J., Wang, W., Kratz, K., Ma, N., Lendlein, A. %D 2019 %J Polydays 2019 - Polymer Science and Engineering in View of Digitalization %T Elasticity of fiber meshes from multiblock copolymers influences endothelial cell behaviors %U %X %0 conference poster %@ %A Saretia, S., Machatschek, R., Schulz, B., Lendlein, A. %D 2019 %J Polydays 2019 - Polymer Science and Engineering in View of Digitalization %T Modulating enzymatic degradation of poly(å-caprolactone) monolayer at the air-water interface by two dimensional cross-linking %U %X %0 conference poster %@ %A Moradian, H., Lendlein, A., Gossen, M. %D 2019 %J Polydays 2019 - Polymer Science and Engineering in View of Digitalization %T Co-transfection Strategies for In Vitro Transcribed mRNA %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2019 %J XXVIII International Materials Research Congress (IMRC) 2019 %T Design and fabrication of multifunctional polymeric devices %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2019 %J Advanced Functional Polymers for Medicine 2019 %T Designing Materials with Multiple Functions with regard to structure-function as well as function-function relations %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2019 %J Controlled Release Society Annual Meeting & Exposition (CRS) %T Multifunctional matrix and carrier materials %U %X %0 conference poster %@ %A Tarazona, N., Machatschek, R., Schulz, B., Prieto, M., Lendlein, A. %D 2019 %J 16th European Conference on Organized Films (ECOF 16) %T Understanding the function of polyester-binding proteins: from bacteria to the air-water interface %U %X %0 conference poster %@ %A Sun, X., Wang, W., Tung, W., Zou, J., Kratz, K., Ma, N., Lendlein, A. %D 2019 %J Advanced Functional Polymers for Medicine (AFPM) 2019 %T Elasticity of fiber meshes from multiblock copolymers influences endothelial cell behaviors %U %X %0 conference poster %@ %A Curio, J., Schröder, M., Park, J., Landmesser, U., Lendlein, A., Reinthaler, M. %D 2019 %J Advanced Functional Polymers for Medicine (AFPM) 2019 %T Intracardiac echocardiography in transcatheter tricuspid-repair with the MitraClip device: Insights from a 3-D printed heart model %U %X %0 conference poster %@ %A Moradian, H., Lendlein, A., Gossen, M. %D 2019 %J Advanced Functional Polymers for Medicine (AFPM) 2019 %T Co-transfection Strategies for In Vitro Transcribed mRNA %U %X %0 conference poster %@ %A Folikumah, M., Neffe, A., Behl, M., Lendlein, A. %D 2019 %J Advanced Functional Polymers for Medicine (AFPM) 2019 %T Thiol-Michael reactions of optically-active mercapto-acids in aqueous medium %U %X %0 conference poster %@ %A Deng, Z., Nie, Y., Zou, J., Sun, X., Wang, W., Ma, N., Lendlein, A. %D 2019 %J Advanced Functional Polymers for Medicine (AFPM) 2019 %T Inhibition of cellular senescence by polydopamine coating to maintain mesenchymal stem cells %U %X %0 journal article %@ 1386-0291 %A Deng, Z., Zou, J., Wang, W., Nie, Y., Tung, W.-T., Ma, N., Lendlein, A. %D 2019 %J Clinical Hemorheology and Microcirculation %N 4 %P 415-424 %R doi:10.3233/CH-199005 %T Dedifferentiation of mature adipocytes with periodic exposure to cold %U https://doi.org/10.3233/CH-199005 4 %X Lipid-containing adipocytes can dedifferentiate into fibroblast-like cells under appropriate culture conditions, which are known as dedifferentiated fat (DFAT) cells. However, the relative low dedifferentiation efficiency with the established protocols limit their widespread applications. In this study, we found that adipocyte dedifferentiation could be promoted via periodic exposure to cold (10°C) in vitro. The lipid droplets in mature adipocytes were reduced by culturing the cells in periodic cooling/heating cycles (10–37°C) for one week. The periodic temperature change led to the down-regulation of the adipogenic genes (FABP4, Leptin) and up-regulation of the mitochondrial uncoupling related genes (UCP1, PGC-1α, and PRDM16). In addition, the enhanced expression of the cell proliferation marker Ki67 was observed in the dedifferentiated fibroblast-like cells after periodic exposure to cold, as compared to the cells cultured in 37°C. Our in vitro model provides a simple and effective approach to promote lipolysis and can be used to improve the dedifferentiation efficiency of adipocytes towards multipotent DFAT cells. %0 book part %@ 2510-3458 %A Mazurek-Budzynska, M., Razzaq, M., Behl, M., Lendlein, A. %D 2019 %J Functional Polymers. Polymers and Polymeric Composites %P 605-663 %R doi:10.1007/978-3-319-92067-2_18-1 %T Shape-Memory Polymers %U https://doi.org/10.1007/978-3-319-92067-2_18-1 %X Shape-memory polymers (SMPs) are stimuli-sensitive materials capable of changing their shape on demand. A shape-memory function is a result of the polymer architecture together with the application of a specific programming procedure. Various possible mechanisms to induce the shape-memory effect (SME) can be realized, which can be based on thermal transitions of switching domains or on reversible molecular switches (e.g., supramolecular interactions, reversible covalent bonds). Netpoints, which connect the switching domains and determine the permanent shape, can be either provided by covalent bonds or by physical intermolecular interactions, such as hydrogen bonds or crystallites. This chapter reviews different ways of implementing the phenomenon of programmable changes in the polymer shape, including the one-way shape-memory effect (1-W SME), triple- and multi-shape effects (TSE/MSE), the temperature-memory effect (TME), and reversible shape-memory effects, which can be realized in constant stress conditions (rSME), or in stress-free conditions (reversible bidirectional shape-memory effect (rbSME)). Furthermore, magnetically actuated SMPs and shape-memory hydrogels (SMHs) are described to show the potential of the SMP technology in biomedical applications and multifunctional approaches. %0 journal article %@ 1525-7797 %A Lendlein, A., Balk, M., Tarazona, N., Gould, O. %D 2019 %J Biomacromolecules %N 10 %P 3627-3640 %R doi:10.1021/acs.biomac.9b01074 %T Bioperspectives for Shape-Memory Polymers as Shape Programmable, Active Materials %U https://doi.org/10.1021/acs.biomac.9b01074 10 %X Within the natural world, organisms use information stored in their material structure to generate a physical response to a wide variety of environmental changes. The ability to program synthetic materials to intrinsically respond to environmental changes in a similar manner has the potential to revolutionize material science. By designing polymeric devices capable of responsively changing shape or behavior based on information encoded into their structure, we can create functional physical behavior, including a shape-memory and an actuation capability. Here we highlight the stimuli-responsiveness and shape-changing ability of biological materials and biopolymer-based materials, plus their potential biomedical application, providing a bioperspective on shape-memory materials. We address strategies to incorporate a shape-memory (actuation) function in polymeric materials, conceptualized in terms of its relationship with inputs (environmental stimuli) and outputs (shape change). Challenges and opportunities associated with the integration of several functions in a single material body to achieve multifunctionality are discussed. Finally, we describe how elements that sense, convert, and transmit stimuli have been used to create multisensitive materials. %0 journal article %@ 1386-0291 %A Wang, W., Xu, X., Li, Z., Kratz, K., Ma, N., Lendlein, A. %D 2019 %J Clinical Hemorheology and Microcirculation %N 2 %P 277-289 %R doi:10.3233/CH-189418 %T Modulating human mesenchymal stem cells using poly(Eta-butyl acrylate) networks in vitro with elasticity matching human arteries %U https://doi.org/10.3233/CH-189418 2 %X Non-swelling hydrophobic poly(n-butyl acrylate) network (cPnBA) is a candidate material for synthetic vascular grafts owing to its low toxicity and tailorable mechanical properties. Mesenchymal stem cells (MSCs) are an attractive cell type for accelerating endothelialization because of their superior anti-thrombosis and immune modulatory function. Further, they can differentiate into smooth muscle cells or endothelial-like cells and secret pro-angiogenic factors such as vascular endothelial growth factor (VEGF). MSCs are sensitive to the substrate mechanical properties, with the alteration of their major cellular behavior and functions as a response to substrate elasticity. Here, we cultured human adipose-derived mesenchymal stem cells (hADSCs) on cPnBAs with different mechanical properties (cPnBA250, Young’s modulus (E) = 250 kPa; cPnBA1100, E = 1100 kPa) matching the elasticity of native arteries, and investigated their cellular response to the materials including cell attachment, proliferation, viability, apoptosis, senescence and secretion. The cPnBA allowed high cell attachment and showed negligible cytotoxicity. F-actin assembly of hADSCs decreased on cPnBA films compared to classical tissue culture plate. The difference of cPnBA elasticity did not show dramatic effects on cell attachment, morphology, cytoskeleton assembly, apoptosis and senescence. Cells on cPnBA250, with lower proliferation rate, had significantly higher VEGF secretion activity. These results demonstrated that tuning polymer elasticity to regulate human stem cells might be a potential strategy for constructing stem cell-based artificial blood vessels. %0 journal article %@ 2059-8521 %A Razzaq, M.Y., Behl, M., Lendlein, A. %D 2019 %J MRS Advances %N 19 %P 1057-1065 %R doi:10.1557/adv.2019.123 %T Magneto-Mechanical Actuators with Reversible Stretching and Torsional Actuation Capabilities %U https://doi.org/10.1557/adv.2019.123 19 %X Composite actuators consisting of magnetic nanoparticles dispersed in a crystallizable multiphase polymer system can be remotely controlled by alternating magnetic fields (AMF). These actuators contain spatially segregated crystalline domains with chemically different compositions. Here, the crystalline domain associated to low melting transition range is responsible for actuation while the crystalline domain associated to the higher melting transition range determines the geometry of the shape change. This paper reports magneto-mechanical actuators which are based on a single crystalline domain of oligo(ω-pentadecalactone) (OPDL) along with covalently integrated iron(III) oxide nanoparticles (ioNPs). Different geometrical modes of actuation such as a reversible change in length or twisting were implemented by a magneto-mechanical programming procedure. For an individual actuation mode, the degree of actuation could be tailored by variation of the magnetic field strengths. This material design can be easily extended to other composites containing other magnetic nanoparticles, e.g. with a high magnetic susceptibility. %0 journal article %@ 0897-4756 %A Zhang, P., Behl, M., Peng, X., Balk, M., Lendlein, A. %D 2019 %J Chemistry of Materials %N 15 %P 5402-5407 %R doi:10.1021/acs.chemmater.9b00363 %T Chemoresponsive Shape-Memory Effect of Rhodium–Phosphine Coordination Polymer Networks %U https://doi.org/10.1021/acs.chemmater.9b00363 15 %X Chemoresponsive polymers are of technological significance for smart sensors or systems capable of molecular recognition. An important key requirement for these applications is the material’s structural integrity after stimulation. We explored whether covalently cross-linked metal ion–phosphine coordination polymers (MPN) can be shaped into any temporary shape and are capable of recovering from this upon chemoresponsive exposure to triphenylphosphine (Ph3P) ligands, whereas the MPN provide structural integrity. Depending on the metal-ion concentration used during synthesis of the MPN, the degree of swelling of the coordination polymer networks could be adjusted. Once the MPN was immersed into Ph3P solution, the reversible ligand-exchange reaction between the metal ions and the free Ph3P in solution causes a decrease of the coordination cross-link density in MPN again. The Ph3P-treated MPN was able to maintain its original shape, indicating a certain stability of shape even after stimulation. In this way, chemoresponsive control of the elastic properties (increase in volume and decrease of mechanical strength) of the MPN was demonstrated. This remarkable behavior motivated us to explore whether the MPN are capable of a chemoresponsive shape-memory effect. In initial experiments, shape fixity of around 60% and shape recovery of almost 90% were achieved when the MPN was exposed to Ph3P in case of rhodium. Potential applications for chemoresponsive shape-memory systems could be shapable semiconductors, e.g., for lighting or catalysts, which provide catalytic activity on demand. %0 journal article %@ 0141-3910 %A Mazurek-Budzynska, M., Behl, M., Razzaq, M.Y., Noechel, U., Rokicki, G., Lendlein, A. %D 2019 %J Polymer Degradation and Stability %P 283-297 %R doi:10.1016/j.polymdegradstab.2019.01.032 %T Hydrolytic stability of aliphatic poly(carbonate-urea-urethane)s: Influence of hydrocarbon chain length in soft segment %U https://doi.org/10.1016/j.polymdegradstab.2019.01.032 %X Based on the DSC analysis, slight increases of melting transitions of PCUUs were observed, which were attributed to structure reorganization related to annealing at 37 °C rather than to the degradation of the PCUU. Tensile strength after 20 weeks of all investigated samples remained in the range of 29–39 MPa, whereas the elongation at break εm decreased only slightly and remained in the range between 670 and 800%. Based on the characterization of degradation products after up to 10 weeks of immersion it was assessed that oligomers are mainly consisting of hard segments containing urea linkages, which could be assigned to hindered-urea dissociation mechanism. The investigations confirmed good resistance of PCUUs to hydrolysis. Only minor changes in the crystallinity, as well as thermal and mechanical properties were observed and depended on hydrocarbon chain length in soft segment of PCUUs. %0 journal article %@ 0168-3659 %A Brunacci, N., Neffe, A., Wischke, C., Naolou, T., Nöchel, U., Lendlein, A. %D 2019 %J Journal of Controlled Release %P 146-156 %R doi:10.1016/j.jconrel.2019.03.004 %T Oligodepsipeptide (nano)carriers: Computational design and analysis of enhanced drug loading %U https://doi.org/10.1016/j.jconrel.2019.03.004 %X High drug loads of nanoparticles are essential to efficiently provide a desired dosage in the required timeframe, however, these conditions may not be reached with so far established degradable matrices. Our conceptual approach for increasing the drug load is based on strengthening the affinity between drug and matrix in combination with stabilizing drug-matrix-hybrids through strong intermolecular matrix interactions. Here, a method for designing such complex drug-matrix hybrids is introduced employing computational methods (molecular dynamics and docking) as well as experimental studies (affinity, drug loading and distribution, drug release from films and nanoparticles). As model system, dexamethasone (DXM), relevant for the treatment of inflammatory diseases, in combination with poly[(rac-lactide)-co-glycolide] (PLGA) as standard degradable matrix or oligo[(3-(S)-sec-butyl)morpholine-2,5-dione]diol (OBMD) as matrix with hypothesized stronger interaction with DXM were investigated. Docking studies predicted higher affinity of DXM to OBMD than PLGA and displayed amide bond participation in hydrogen bonding with OBMD. Experimental investigations on films and nanoparticles, i.e. matrices of different shapes and sizes, confirmed this phenomenon as shown e.g. by a ~10 times higher solid state solubility of DXM in OBMD than in PLGA. DXM-loaded particles of ~ 150 nm prepared by nanoprecipitation in aqueous environment had a drug loading (DL) up to 16 times higher when employing OBMD as matrix compared to PLGA carriers due to enhanced drug retention in the OBMD phase. Importantly, drug relase periods were not altered as the release from films and particles was mainly ruled by the diffusion length as well as matrix degradation rather than the matrix type, which can be assigned to water diffusing into the matrix and breaking up of drug-matrix hydrogen bonds. Overall, the presented design and fabrication scheme showed predictive power and might universally enable the screening of drug/matrix interactions particularly to expand the oligodepsipeptide platform technology, e.g. by varying the depsipeptide side chains, for drug carrier and release systems. %0 journal article %@ 2373-9878 %A Hauser, S., Wodtke, R., Tondera, C., Wodtke, J., Neffe, A., Hampe, J., Lendlein, A., Löser, R., Pietzsch, J. %D 2019 %J ACS Biomaterials Science & Engineering %N 11 %P 5979-5989 %R doi:10.1021/acsbiomaterials.9b01299 %T Characterization of Tissue Transglutaminase as a Potential Biomarker for Tissue Response toward Biomaterials %U https://doi.org/10.1021/acsbiomaterials.9b01299 11 %X Tissue transglutaminase (TGase 2) is proposed to be important for biomaterial–tissue interactions due to its presence and versatile functions in the extracellular environment. TGase 2 catalyzes the cross-linking of proteins through its Ca2+-dependent acyltransferase activity. Moreover, it enhances the interactions between fibronectin and integrins, which in turn mediates the adhesion, migration, and motility of the cells. TGase 2 is also a key player in the pathogenesis of fibrosis. In this study, we investigated whether TGase 2 is present at the biomaterial–tissue interface and might serve as an informative biomarker for the visualization of tissue response toward gelatin-based biomaterials. Two differently cross-linked hydrogels were used, which were obtained by the reaction of gelatin with lysine diisocyanate ethyl ester. The overall expression of TGase 2 by endothelial cells, macrophages, and granulocytes was partly influenced by contact to the hydrogels or their degradation products, although no clear correlation was evidenced. In contrast, the secretion of TGase 2 differed remarkably between the different cells, indicating that it might be involved in the cellular reaction toward gelatin-based hydrogels. The hydrogels were implanted subcutaneously in immunocompetent, hairless SKH1-Elite mice. Ex vivo immunohistochemical analysis of tissue sections over 112 days revealed enhanced expression of TGase 2 around the hydrogels, in particular at days 14 and 21 post-implantation. The incorporation of fluorescently labeled cadaverine derivatives for the detection of active TGase 2 was in accordance with the results of the expression analysis. The presence of an irreversible inhibitor of TGase 2 led to attenuated incorporation of the cadaverines, which verified the catalytic action of TGase 2. Our in vitro and ex vivo results verified TGase 2 as a potential biomarker for tissue response toward gelatin-based hydrogels. In vivo, no TGase 2 activity was detectable, which is mainly attributed to the unfavorable physicochemical properties of the cadaverine probe used. %0 journal article %@ 1386-0291 %A Krüger-Genge, A., Dietze, S., Yan, W., Liu, Y., Fang, L., Kratz, K., Lendlein, A., Jung, F. %D 2019 %J Clinical Hemorheology and Microcirculation %N 4 %P 511-529 %R doi:10.3233/CH-189317 %T Endothelial cell migration, adhesion and proliferation on different polymeric substrates %U https://doi.org/10.3233/CH-189317 4 %X The study revealed that the wettability of polymers affected not only the initial adherence but also the migration of EC, which is of importance for the proliferation and ultimately the endothelialization of polymer-based biomaterials. %0 journal article %@ 1525-7797 %A Tarazona, N.A., Machatschek, R., Schulz, B., Prieto, M.A., Lendlein, A. %D 2019 %J Biomacromolecules %N 9 %P 3242-3252 %R doi:10.1021/acs.biomac.9b00069 %T Molecular Insights into the Physical Adsorption of Amphiphilic Protein PhaF onto Copolyester Surfaces %U https://doi.org/10.1021/acs.biomac.9b00069 9 %X Phasins are amphiphilic proteins located at the polymer–cytoplasm interface of bacterial polyhydroxyalkanoates (PHA). The immobilization of phasins on biomaterial surfaces is a promising way to enhance the hydrophilicity and supply cell-directing elements in bioinstructing processes. Optimizing the physical adsorption of phasins requires deep insights into molecular processes during polymer–protein interactions to preserve their structural conformation while optimizing surface coverage. Here, the assembly, organization, and stability of phasin PhaF from Pseudomonas putida at interfaces is disclosed. The Langmuir technique, combined with in situ microscopy and spectroscopic methods, revealed that PhaF forms stable and robust monolayers at different temperatures, with an almost flat orientation of its α-helix at the air–water interface. PhaF adsorption onto preformed monolayers of poly[(3-R-hydroxyoctanoate)-co-(3-R-hydroxyhexanoate)] (PHOHHx), yields stable mixed layers below π = ∼15.7 mN/m. Further insertion induces a molecular reorganization. PHOHHx with strong surface hydrophobicity is a more adequate substrate for PhaF adsorption than the less hydrophobic poly[(rac-lactide)-co-glycolide] (PLGA). The observed orientation of the main axis of the protein in relation to copolyester interfaces ensures the best exposure of the hydrophobic residues, providing a suitable coating strategy for polymer functionalization. %0 conference poster %@ %A Lützow, K., Weigel, T., Kosmella, H., Behl, M., Lendlein, A. %D 2019 %J AFPM - Advanced Functional Polymers for Medicine 2019 %T Shape Recovery of Polymeric Nanocomposite Foams by Direct and Inductive Heating %U %X %0 journal article %@ 1748-605X %A Bhuvanesh, T., Machatschek, R., Lysyakova, L., Kratz, K., Schulz, B., Ma, N., Lendlein, A. %D 2019 %J Biomedical Materials %N 2 %P 024101 %R doi:10.1088/1748-605X/aaf464 %T Collagen type-IV Langmuir and Langmuir-Schaefer layers as model biointerfaces to direct stem cell adhesion %U https://doi.org/10.1088/1748-605X/aaf464 2 %X In biomaterial development, the design of material surfaces that mimic the extra-cellular matrix (ECM) in order to achieve favorable cellular instruction is rather challenging. Collagen-type IV (Col-IV), the major scaffolding component of Basement membranes, a specialized ECM with multiple biological functions, has the propensity to form networks by self-assembly and supports adhesion of cells such as endothelial cells or stem cells. The preparation of biomimetic Col-IV network like layers to direct cell responses is difficult. We hypothesize that the morphology of the layer, and especially the density of the available adhesion sites, regulates the cellular adhesion to the layer. The Langmuir monolayer technique allows for preparation of thin layers with precisely controlled packing density at the air-water (A-W) interface. Transferring these layers onto cell culture substrates using the Langmuir Schäfer (LS) technique should therefore provide a pathway for preparation of BM mimicking layers with controlled cell adherence properties. In situ characterization using ellipsometry and polarization modulation-infrared reflection absorption spectroscopy of Col-IV layer during compression at the A-W interface reveal that there is linear increase of surface molecule concentration with negligible orientational changes up to a surface pressure of 25 mNcenterdotm<sup>-1</sup>. Smooth and homogeneous Col-IV network-like layers are successfully transferred by LS method at 15 mNcenterdotm<sup>-1</sup> onto poly(ethyleneterepthalate) (PET), which is a common substrate for cell culture. In contrast, the organization of Col-IV on PET prepared by the traditionally employed solution deposition method results in rather inhomogeneous layers with the appearance of aggregates and multilayers. Progressive increase in the number of early adherent mesenchymal stem cells (MSCs) after 24 h by controlling the Col-IV density by LS transfer at 10, 15 and 20 mNcenterdotm<sup>-1</sup> on PET is shown. LS method offers the possibility to control protein characteristics on biomaterial surfaces such as molecular density and thereby, modulate cell responses. %0 journal article %@ 2159-6859 %A Machatschek, R., Schoene, A.-C., Raschdorf, E., Ihlenburg, R.B.J., Schulz, B., Lendlein, A. %D 2019 %J MRS Communications %N 1 %P 170-180 %R doi:10.1557/mrc.2019.21 %T Interfacial properties of morpholine-2,5-dione-based oligodepsipeptides and multiblock copolymers %U https://doi.org/10.1557/mrc.2019.21 1 %X Oligodepsipeptides (ODPs) with alternating amide and ester bonds prepared by ring-opening polymerization of morpholine-2,5-dione derivatives are promising matrices for drug delivery systems and building blocks for multifunctional biomaterials. Here, we elucidate the behavior of three telechelic ODPs and one multiblock copolymer containing ODP blocks at the air–water interface. Surprisingly, whereas the oligomers and multiblock copolymers crystallize in bulk, no crystallization is observed at the air–water interface. Furthermore, polarization modulation infrared reflection absorption spectroscopy is used to elucidate hydrogen bonding and secondary structures in ODP monolayers. The results will direct the development of the next ODP-based biomaterial generation with tailored properties for highly sophisticated applications. %0 journal article %@ 2296-2646 %A Naolou, T., Lendlein, A., Neffe, A.T. %D 2019 %J Frontiers in Chemistry %P 346 %R doi:10.3389/fchem.2019.00346 %T Amides as Non-polymerizable Catalytic Adjuncts Enable the Ring-Opening Polymerization of Lactide With Ferrous Acetate Under Mild Conditions %U https://doi.org/10.3389/fchem.2019.00346 %X Sn-based catalysts are effective in the ring-opening polymerization (ROP) but are toxic. Fe(OAc)2 used as an alternative catalyst is suitable for the ROP of lactide only at higher temperatures (>170°C), associated with racemization. In the ROP of ester and amide group containing morpholinediones with Fe(OAc)2 to polydepsipeptides at 135°C, ester bonds were selectively opened. Here, it was hypothesized that ROP of lactones is possible with Fe(OAc)2 when amides are present in the reactions mixture as Fe-ligands could increase the solubility and activity of the metal catalytic center. The ROP of lactide in the melt with Fe(OAc)2 is possible at temperatures as low as 105°C, in the presence of N-ethylacetamide or N-methylbenzamide as non-polymerizable catalytic adjuncts (NPCA), with high conversion (up to 99 mol%) and yield (up to 88 mol%). Polydispersities of polylactide decreased with decreasing reaction temperature to ≤ 1.1. NMR as well as polarimetric studies showed that no racemization occurred at reaction temperatures ≤145°C. A kinetic study demonstrated a living chain-growth mechanism. MALDI analysis revealed that no side reactions (e.g., cyclization) occurred, though transesterification took place. %0 journal article %@ 1386-0291 %A Reinthaler, M., Baeckemo-Johansson, J., Braune, S., Al-Hindwan, H.S.A., Lendlein, A., Jung, F. %D 2019 %J Clinical Hemorheology and Microcirculation %N 2 %P 183-191 %R doi:10.3233/CH-189410 %T Shear-induced platelet adherence and activation in an in-vitro dynamic multiwell-plate system %U https://doi.org/10.3233/CH-189410 2 %X Differences in the thrombogenicity of the studied polymers were more pronounced when tested at high agitation speed due to the induced shear stresses. Testing under varying shear stresses, thus, led to a different evaluation of the implant thrombogenicity, which emphasizes the need for testing under various flow conditions. Our data further confirmed earlier findings where the same reference implants were tested under static (and not dynamic) conditions and with fresh human platelet rich plasma instead of whole blood. This supports that the application of common reference materials may improve inter-study comparisons, even under varying test conditions. %0 journal article %@ 0964-1726 %A Balk, M., Behl, M., Lendlein, A. %D 2019 %J Smart Materials and Structures %N 5 %P 055026 %R doi:10.1088/1361-665X/ab0e91 %T Quadruple-shape hydrogels %U https://doi.org/10.1088/1361-665X/ab0e91 5 %X The capability of directed movements by two subsequent shape changes could be implemented in shape-memory hydrogels by incorporation of two types of crystallizable side chains. While in non-swollen polymer networks even more directed movements could be realized, the creation of multi-shape hydrogels is still a challenge. We hypothesize that a quadruple-shape effect in hydrogels can be realized, when a swelling capacity almost independent of temperature is generated, whereby directed movements could be enabled, which are not related to swelling. In this case, entropy elastic recovery could be realized by hydrophilic segments and the fixation of different macroscopic shapes by means of three semi-crystalline side chains generating temporary crosslinks. Monomethacrylated semi-crystalline oligomers were connected as side chains in a hydrophilic polymer network via radical copolymerization. Computer assisted modelling was utilized to design a demonstrator capable of complex shape shifts by creating a casting mold via 3D printing from polyvinyl alcohol. The demonstrator was obtained after copolymerization of polymer network forming components within the mold, which was subsequently dissolved in water. A thermally-induced quadruple-shape effect was realized after equilibrium swelling of the polymer network in water. Three directed movements were successfully obtained when the temperature was continuously increased from 5 °C to 90 °C with a recovery ratio of the original shape above 90%. Hence, a thermally-induced quadruple-shape effect as new record for hydrogels was realized. Here, the temperature range for the multi-shape effect was limited by water as swelling media (0 °C–100 °C), simultaneously distinctly separated thermal transitions were required, and the overall elasticity indispensable for successive deformations was reduced as result of partially chain segment orientation induced by swelling in water. Conclusively the challenges for penta- or hexa-shape gels are the design of systems enabling higher elastic deformability and covering a larger temperature range by switching to a different solvent. %0 journal article %@ 0261-3069 %A Jiang, Y., Mansfeld, U., Fang, L., Kratz, K., Lendlein, A. %D 2019 %J Materials and Design %P 107530 %R doi:10.1016/j.matdes.2018.12.002 %T Temperature-induced evolution of microstructures on poly[ethylene-co-(vinyl acetate)] substrates switches their underwater wettability %U https://doi.org/10.1016/j.matdes.2018.12.002 %X Here, we present switchable underwater aerophobicity of hydrophobic polymeric substrates, which respond to heat with multilevel micro- and nanotopographical changes. The cross-linked poly[ethylene-co-(vinyl acetate)] substrates possess arrays of microcylinders with a nanorough top surface. It is hypothesized that the specific micro-/nanotopography of the surface allows trapping of a water film at the micro interspace and in this way generates the aerophobic behavior. The structured substrates were programmed to a temporarily stable, nanoscale flat substrate showing aerophilic behavior. Upon heating, the topographical changes caused a switch in contact angle from aerophilic to aerophobic for approaching air bubbles. In this way, the initial adhesion of air bubbles to the programmed flat substrate could be turned into repellence for the recovered substrate surface. The temperature at which the repellence of air bubbles starts can be adjusted from 58 ± 3 °C to 73 ± 3 °C by varying the deformation temperature applied during the temperature-memory programming procedure. The presented actively switching polymeric substrates are attractive candidates for applications, where an on-demand gas bubble repellence is advantageous. %0 journal article %@ 2159-6859 %A Jiang, Y., Mansfeld, U., Kratz, K., Lendlein, A. %D 2019 %J MRS Communications %N 1 %P 181-188 %R doi:10.1557/mrc.2019.24 %T Programmable microscale stiffness pattern of flat polymeric substrates by temperature-memory technology %U https://doi.org/10.1557/mrc.2019.24 1 %X Temperature-memory technology was utilized to generate flat substrates with a programmable stiffness pattern from cross-linked poly(ethylene-co-vinyl acetate) substrates with cylindrical microstructures. Programmed substrates were obtained by vertical compression at temperatures in the range from 60 to 100 °C and subsequent cooling, whereby a flat substrate was achieved by compression at 72 °C, as documented by scanning electron microscopy and atomic force microscopy (AFM). AFM nanoindentation experiments revealed that all programmed substrates exhibited the targeted stiffness pattern. The presented technology for generating polymeric substrates with programmable stiffness pattern should be attractive for applications such as touchpads, optical storage, or cell instructive substrates. %0 conference poster %@ %A Pieper, Y., Kratz, K., Heuchel, M., Lendlein, A. %D 2019 %J Microscopy Conference 2019 %T In-situ measurement of contact angles on single multifunctional; porous polymer microparticles utilizing ESEM %U %X %0 conference poster %@ %A Izraylit, V., Kratz, K., Lendlein, A. %D 2019 %J Polydays 2019 - Polymer Science and Engineering in View of Digitalization %T Controlling Actuation Behaviour in Shape-Memory Polymer Blends by Tailoring Supramolecular lnteractions %U %X %0 conference lecture %@ %A Izraylit, V., Kratz, K., Lendlein, A. %D 2019 %J MRS Fall Meeting 2019 %T Controlling actuation behaviour in shape-memory polymer blends by tailoring supramolecular interactions %U %X %0 journal article %@ 2058-8437 %A Lendlein, A., Gould, O.E.C. %D 2019 %J Nature Reviews : Materials %P 116-133 %R doi:10.1038/s41578-018-0078-8 %T Reprogrammable recovery and actuation behaviour of shape-memory polymers %U https://doi.org/10.1038/s41578-018-0078-8 %X Shape memory is the capability of a material to be deformed and fixed into a temporary shape. Recovery of the original shape can then be triggered only by an external stimulus. Shape-memory polymers are highly deformable materials that can be programmed to recover a memorized shape in response to a variety of environmental and spatially localized stimuli as a one-way effect. The shape-memory function can also be generated as a reversible effect enabling actuation behaviour through macroscale deformation and processing, specifically by dictating the macromolecular orientation of actuation units and of the skeleton structure of geometry-determining units in the polymers. Shape-memory polymers can be programmed and reprogrammed into arbitrary shapes. Both recovery and actuation behaviour are reprogrammable. In this Review, we outline the common basis and key differences between the two shape-memory behaviours of polymers in terms of mechanism, fabrication schemes and characterization methods. We discuss which combination of macromolecular architecture and macroscale processing is necessary for coordinated, decentralized and responsive physical behaviour. The extraction of relevant thermomechanical information is described, and design criteria are shown for microscale and macroscale morphologies to gain high levels of recovered or actuation strains as well as on-demand 2D-to-3D shape transformations. Finally, real-world applications and key future challenges are highlighted. %0 conference lecture %@ %A Gould, O., Kratz, K., Lendlein, A. %D 2019 %J BIFTM Seminar %T Implementing and quantifying the shape-memory effect of polymeric micro/nanowires %U %X %0 journal article %@ 1748-605X %A Saretia, S., Machatschek, R., Schulz, B., Lendlein, A. %D 2019 %J Biomedical Materials %N 3 %P 034103 %R doi:10.1088/1748-605X/ab0cef %T Reversible 2D networks of oligo(Epsilon-caprolactone) at the air–water interface %U https://doi.org/10.1088/1748-605X/ab0cef 3 %X Hydroxyl terminated oligo(ε-caprolactone) (OCL) monolayers were reversibly cross-linked forming two dimensional networks (2D) at the air–water interface. The equilibrium reaction with glyoxal as the cross-linker is pH-sensitive. Pronounced contraction in the area of the prepared 2D OCL films in dependence of surface pressure and time revealed the process of the reaction. Cross-linking inhibited crystallization and retarded enzymatic degradation of the OCL film. Altering the subphase pH led to a cleavage of the covalent acetal cross-links. The reversibility of the covalent acetal cross-links was proved by observing an identical isotherm as non-cross-linked sample. Besides as model systems, these customizable reversible OCL 2D networks are intended for use as pH responsive drug delivery systems or functionalized cell culture substrates. %0 journal article %@ 0964-1726 %A Zhang, Q., Rudolph, T., Benitez, A.J., Gould, O.E.C., Behl, M., Kratz, K., Lendlein, A. %D 2019 %J Smart Materials and Structures %N 5 %P 055037 %R doi:10.1088/1361-665X/ab10a1 %T Temperature-controlled reversible pore size change of electrospun fibrous shape-memory polymer actuator based meshes %U https://doi.org/10.1088/1361-665X/ab10a1 5 %X Fibrous membranes capable of dynamically responding to external stimuli are highly desirable in textiles and biomedical materials, where adaptive behavior is required to accommodate complex environmental changes. For example, the creation of fabrics with temperature-dependent moisture permeability or self-regulating membranes for air filtration is dependent on the development of materials that exhibit a reversible stimuli-responsive pore size change. Here, by imbuing covalently crosslinked poly(ε-caprolactone) (cPCL) fibrous meshes with a reversible bidirectional shape-memory polymer actuation (rbSMPA) we create a material capable of temperature-controlled changes in porosity. Cyclic thermomechanical testing was used to characterize the mechanical properties of the meshes, which were composed of randomly arranged microfibers with diameters of 2.3 ± 0.6 μm giving an average pore size of approx. 10 μm. When subjected to programming strains of ε m = 300% and 100% reversible strain changes of εʹrev = 22% ± 1% and 6% ± 1% were measured, with switching temperature ranges of 10 °C–30 °C and 45 °C–60 °C for heating and cooling, respectively. The rbSMPA of cPCL fibrous meshes generated a microscale reversible pore size change of 11% ± 3% (an average of 1.5 ± 0.6 μm), as measured by scanning electron microscopy. The incorporation of a two-way shape-memory actuation capability into fibrous meshes is anticipated to advance the development and application of smart membrane materials, creating commercially viable textiles and devices with enhanced performance and novel functionality. %0 book part %@ %A Razzaq, M.Y., Reinthaler, M., Schroeder, M., Wischke, C., Lendlein, A. %D 2019 %J Encyclopedia of Biomedical Engineering, Biomaterials: Biomaterial Applications and Advanced Medical Technologies %P 394-405 %R doi:10.1016/B978-0-12-801238-3.11041-4 %T Shape-memory polymer medical devices %U https://doi.org/10.1016/B978-0-12-801238-3.11041-4 %X Shape-memory polymers (SMPs) are stimuli-responsive materials, which allow spatially directed movements of devices upon external stimulation. This programmed movement is highly defined as it relies on the recovery of a device from a temporary, second shape to a permanent shape. The types of applicable stimuli to induce the shape switching as well as the specific conditions of material response can be tuned by altering the chemistry as well as the material organization on different hierarchical levels. Their ability to rapidly and automatically respond to changes in the environment makes SMPs suitable for a variety of biomedical applications, particularly for devices for minimally invasive surgery and for the delivery of therapeutics and cells. This article introduces the concepts of the shape-memory effect in polymers and their contribution to upcoming clinical demands for smart medical devices. %0 journal article %@ 1042-7147 %A Luetzow, K., Hommes-Schattmann, P.J., Neffe, A.T., Ahmad, B., Williams, G.R., Lendlein, A. %D 2019 %J Polymers for Advanced Technologies %N 5 %P 1165-1172 %R doi:10.1002/pat.4331 %T Perfluorophenyl azide functionalization of electrospun poly(para-dioxanone) %U https://doi.org/10.1002/pat.4331 5 %X Strategies to surface‐functionalize scaffolds by covalent binding of biologically active compounds are of fundamental interest to control the interactions between scaffolds and biomolecules or cells. Poly(para‐dioxanone) (PPDO) is a clinically established polymer that has shown potential as temporary implant, eg, for the reconstruction of the inferior vena cava, as a nonwoven fiber mesh. However, PPDO lacks suitable chemical groups for covalent functionalization. Furthermore, PPDO is highly sensitive to hydrolysis, reflected by short in vivo half‐life times and degradation during storage. Establishing a method for covalent functionalization without degradation of this hydrolyzable polymer is therefore important to enable the surface tailoring for tissue engineering applications. It was hypothesized that treatment of PPDO with an N‐hydroxysuccinimide ester group bearing perfluorophenyl azide (PFPA) under UV irradiation would allow efficient surface functionalization of the scaffold. X‐ray photoelectron spectroscopy and attenuated total reflectance Fourier‐transformed infrared spectroscopy investigation revealed the successful binding, while a gel permeation chromatography study showed that degradation did not occur under these conditions. Coupling of a rhodamine dye to the N‐hydroxysuccinimide esters on the surface of a PFPA‐functionalized scaffold via its amine linker showed a homogenous staining of the PPDO in laser confocal microscopy. The PFPA method is therefore applicable even to the surface functionalization of hydrolytically labile polymers, and it was demonstrated that PFPA chemistry may serve as a versatile tool for the (bio‐)functionalization of PPDO scaffolds. %0 conference lecture %@ %A Lendlein, A. %D 2019 %J Webinar „Grand challenges of multifunctional materials“; PhysicsWorld %T Function-function relations in multifunctional materials %U %X %0 conference poster %@ %A Baeckemo-Johansson, J., Reinthaler, M., Braune, S., Lendlein, A., Jung, F. %D 2018 %J International Biotech Innovation Days, IBID %T Shear-induced platelet adherence and activation in a dynamic multiwell-plate system %U %X %0 conference poster %@ %A Saretia, S., Machatschek, R., Schulz, B., Lendlein, A. %D 2018 %J Advanced Functional Polymers for Medicine, AFPM 2018 %T Modulating Enzymatic Degradation of Poly(ε-caprolactone) Monolayer at Air-water interface by Two Dimensional Crosslinking %U %X %0 conference poster %@ %A Friess, F., Roch, B., Seifert, B., Lendlein, A., Wischke, C. %D 2018 %J Advanced Functional Polymers for Medicine, AFPM 2018 %T Limited Shape-dependency of Phagocytosis for Polymer Micronetworks %U %X %0 conference poster %@ %A Vijaya Bhaskar, T.B., Machatschek, R., Lysyakova, L., Kratz, K., Schulz, B., Ma, N., Lendlein, A. %D 2018 %J Advanced Functional Polymers for Medicine, AFPM 2018 %T Collagen type-IV Langmuir-Schaefer films as substrates to direct mesenchymal stem cell adherence %U %X %0 conference poster %@ %A Eschborn, J., Loewenberg, C., Benitez, A.J., Thiels, K., Kratz, K., Ghods, M., Lendlein, A. %D 2018 %J Advanced Functional Polymers for Medicine, AFPM 2018 %T pH Changes of Aqueous Media Caused by Degradation of Suture Materials %U %X %0 conference lecture %@ %A Razzaq, M.Y., Behl, M., Lendlein, A. %D 2018 %J 27th International Materials Research Congress %T Thermally-Induced Actuation of Magnetic Nanocomposites Based on Oligo(Omega-Pentadecalactone) and Covalently Integrated Magnetic Nanoparticles %U %X %0 conference poster %@ %A Mazurek-Budzynska, M., Razzaq, M., Noechel, U., Behl, M., Rokicki, G., Lendlein, A. %D 2018 %J Advanced Functional Polymers for Medicine, AFPM 2018 %T Hydrolytic stability of aliphatic poly(carbonate-urea-urethane)s %U %X %0 conference lecture %@ %A Machatschek, R., Schulz, B., Lendlein, A. %D 2018 %J 27th International Materials Research Congress %T The influence of pH on the molecular degradation mechanism of PLGA %U %X %0 conference poster %@ %A Rudolph, T., Farhan, M., Noechel, U., Yan, W., Kratz, K., Lendlein, A. %D 2018 %J Advanced Functional Polymers for Medicine, AFPM 2018 %T Noncontinuously Responding Polymeric Actuators %U %X %0 conference lecture %@ %A Farhan, M., Rudolph, T., Kratz, K., Lendlein, A. %D 2018 %J 27th International Materials Research Congress %T Torsional Fiber Actuators from Shape-memory Polymer %U %X %0 conference lecture %@ %A Nie, Y., Wang, W., Xu, X., Zou, J., Bhuvanesh, T., Schulz, B., Ma, N., Lendlein, A. %D 2018 %J 37. Jahrestagung Deutsche Gesellschaft fuer Klinische Mikrozirkulation und Haemorheologie %T Enhancement of human induced pluripotent stem cells adhesion through multilayer laminin coating %U %X %0 conference lecture %@ %A Zou, J., Wang, W., Kratz, K., Xu, X., Nie, Y., Ma, N., Lendlein, A. %D 2018 %J 37. Jahrestagung Deutsche Gesellschaft fuer Klinische Mikrozirkulation und Haemorheologie %T Evaluation of human mesenchymal stem cell senescence, differentiation and secretion behavior cultured on polycarbonate cell culture inserts %U %X %0 conference lecture %@ %A Yan, W., Fang, L., Noechel, U., Gould, O.E.C., Behl, M., Kratz, K., Lendlein, A. %D 2018 %J 27th International Materials Research Congress %T Investigating the Roles of Crystallizable and Glassy Switching Segments within Multiblock Copolymer Shape-Memory Materials %U %X %0 conference lecture %@ %A Reinthaler, M., Baeckemo-Johansson, J., Braune, S., Al-Hindwan, H.S.A., Lendlein, A., Jung, F. %D 2018 %J Joint Conference of Three Societies: European Society of Clinical Hemorheology and Miclrocirculation, International Society of Biorheology, International Society of Clinical Hemorheology, ESCHM-ISB-ISCH 2018 %T Shear-induced platelet adherence and activation in an in-vitro dynamic multiwell-plate system %U %X %0 conference lecture %@ %A Schroeter, M., Lach, L., Lendlein, A. %D 2018 %J Marie-Curie Tag am Marie-Curie-Gymnasium %T Kunststoffe in der Medizin – Neue Entwicklungen %U %X %0 conference poster %@ %A Balk, M., Mazurek-Budzynska, M., Behl, M., Lendlein, A. %D 2018 %J Advanced Functional Polymers for Medicine, AFPM 2018 %T Polycationic Particles Based on Polyethyleneimine and Poly(ethylene glycol) Functionalized Oligoester %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J CLINAM 2018 %T Nano-structured and Nano-sized Shape-memory Polymers for Biomedical Applications %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J 14th International Ceramics Congress and 8th Forum on New Materials, CIMTEC 2018 %T Implementing multifunctionality in polymer-based biomaterials %U %X %0 journal article %@ 2059-8521 %A Mazurek-Budzynska, M., Balk, M., Behl, M., Lendlein, A. %D 2018 %J MRS Advances %N 50 %P 3033-3040 %R doi:10.1557/adv.2018.407 %T Polyethyleneimine and Poly(ethylene glycol) Functionalized Oligoester Based Polycationic Particles %U https://doi.org/10.1557/adv.2018.407 50 %X Polycationic particles based on a degradable oligoester core are interesting candidate materials for the transfection of polyanionic macromolecules like DNA, which would enable the degradation after delivery of condensed molecules. Good transfection efficiencies can be obtained when the size of the polyplex (containing both polycationic nanoparticles and polyanionic macromolecules) does not exceed 120 nm. Therefore, here we explored how size, but also dispersity, and surface charge of these carrier systems can be adjusted by variation of the block copolymer composition or the presence and ratio of a co-assembly agent. Polycationic particles were obtained based on an amphiphilic triblock copolymer from oligo[(ε-caprolactone)-co-glycolide] (CG) functionalized with polyethyleneimine (PEI) and diblock copolymer based on poly(ethylene glycol) (PEG) modified with CG. A second series of particles was created, in which the oligoester blocks contained only ε-caprolactone units, therefore the effect of the presence of glycolide units was also studied. In both series, the ratio between di- and triblock copolymers was systematically varied. Nano-sized particles ranging from 34.5 ± 0.2 nm to 97.9 ± 0.3 nm with controllable positive surface charges between 2.9 ± 0.2 mV and 18.1 ± 0.5 mV were obtained by self-assembly in PBS solution under intensive stirring. The incorporation of PEG-C diblock copolymers resulted in an increase of particle size, however no specific relation between composition, size, and polydispersity was observed. In case of PEG-CG diblock copolymers a rather systematic increase of the particles’ size with increasing content of diblock copolymer was shown. Furthermore, with a decrease of content of diblock copolymer in the particle structure zeta potential strongly increased. Additionally, the content of glycolide units in triblock copolymer increased the zeta potential of PEI-CG-PEI-based particles in comparison to PEI-C-PEI-based ones. Therefore, obtained particles could be used as potential target-oriented polycationic macromolecules for carrier systems. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J Annual Meeting of the German Pharmaceutical Society - DPhG %T Nano carriers and structured hydrogels containing amino acids %U %X %0 conference lecture %@ %A Wischke, C., Ceylan Tuncaboylu, D., Friess, F., Lendlein, A. %D 2018 %J Annual Meeting of the German Pharmaceutical Society - DPhG %T A multifunctional system for on-demand protein release %U %X %0 conference lecture %@ %A Razzaq, M., Behl, M., Lendlein, A. %D 2018 %J XXVII International Materials Research Congress - IMRC 2018 %T Thermally-triggered actuators based on oligo(ω-pentadecalactone) hybrid nanocomposites %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J Advanced Functional Polymers for Medicine, AFPM 2018 %T Reprogrammable soft shape-memory actuators with the option of degradability and self-healing %U %X %0 conference lecture %@ %A Wischke, C., Friess, F., Lendlein, A. %D 2018 %J 5th Symposium on Innovative Polymers for Controlled Delivery (SIPCD) 2018 %T Polymer network carriers that switch their shape %U %X particular, a switching of particles towards increased aspect ratios will be explored. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J 5th Symposium on Innovative Olymers for Controlled Delivery (SIPCD) 2018 %T Multifunctional polymer systems for controlled drug release and transport %U %X potential to combine efficient transfection capability with low toxicity of the transfection agent. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J Langer Symposium (Celebrating 42 Years of Bob Langer´s Science and 70th Birthday Celebration) %T Driven by Vision - Transforming Polymers %U %X %0 conference lecture %@ %A Machatschek, R., Schulz, B., Lendlein, A. %D 2018 %J XXVII International Materials Research Congress - IMRC 2018 %T Langmuir monolayers as tools to study molecular degradation of aliphatic polyesters %U %X chains can be calculated from the area reduction curves. %0 conference poster %@ %A Schulz, B., Lendlein, A. %D 2018 %J Potsdamer Tag der Wissenschaften 2018 %T Polymerabbau im Zeitraffer %U %X %0 journal article %@ 2059-8521 %A Balk, M., Lendlein, A., Behl, M. %D 2018 %J MRS Advances %N 49 %P 2965-2973 %R doi:10.1557/adv.2018.319 %T High-Throughput Synthesis of Oligo(Epsilon-caprolactone) / Oligotetrahydrofuran Based Polyurethanes %U https://doi.org/10.1557/adv.2018.319 49 %X In this work, PUs based on oligo(ε-caprolactone) (OCL) / oligotetrahydrofuran (OTHF) as model components were designed utilizing HT synthesis enabling the quantitative determination of the optimized ratio between reactive end-groups via fully automated syntheses without major characterization effort of end group functionality. The semi-crystalline oligomeric telechelics were connected with a diisocyanate and OCL with a molecular weight of 2, 4, or 8 kg∙mol-1 was integrated. Here, optimized molecular weights between 90 ± 10 kg∙mol-1 (in case of OCL 8 kg∙mol-1) and 260 ± 30 kg∙mol-1 (in case of OCL 2 kg∙mol-1) were obtained with an isocyanate content of 120 mol%, whereby 100 mol% of isocyanate groups resulted only in molecular weights between 60 ± 6 kg∙mol-1 (OCL 8 kg∙mol-1) and 80 ± 10 kg∙mol-1 (OCL 2 kg∙mol-1). In addition to the optimized ratio between isocyanate and hydroxy end groups, quantitative influences of the OCL chain length and overall molecular weights of PUs on thermal and mechanical properties were detected. The melting temperatures (Tms) of OCL and OTHF domains were well separated for PUs of low molecular weight, the temperature interval between the Tms decreased when the molecular weight of the PUs was increased, and were even overlapping towards one broad Tm, when OCL 2 kg∙mol-1 was incorporated. The storage modulus E’ was highly dependent on OCL chain length exhibiting an increase with increasing molecular weight of OCL from 220 MPa to 440 MPa at 0 °C and decreased with increasing chain length of PUs. The elongation at break (εb) was analyzed below and above Tm of OTHF resulting in εb = 780-870% at 0 °C and εb = 510-830% at 30 °C for PUs of high molecular weight. Accordingly, stretchability of PUs was almost independent of the state of OTHF (semi crystalline or amorphous) but correlated with the OCL precursor chain length (increasing εb with increasing chain length) and overall molecular weight of PUs (PUs at higher molecular weight exhibited higher εb). Hence, the analysis of these quantitative influences between macromolecular structure of multiblock copolymers and the resulting properties (well separated Tms versus overlapping melting transition, improvement of stretchability) would enable the design of new tailored PUs. %0 lecture %@ %A Lendlein, A., Schulz, B., Schroeter, M., Behl, M. %D 2018 %J %T Polymers in Medicine %U %X %0 lecture %@ %A Lendlein, A. %D 2018 %J %T Makro 2: Advanced topics in polymer synthesis %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J Vom Material zur Innovation, Materialinnovationen 2018 %T Strukturierte Biomaterialien %U %X %0 conference lecture %@ %A Wang, W., Xu, X., Li, Z., Kratz, K., Ma, N., Lendlein, A. %D 2018 %J Joint Conference of Three Societies: European Society of Clinical Hemorheology and Miclrocirculation, International Society of Biorheology, International Society of Clinical Hemorheology, ESCHM-ISB-ISCH 2018 %T Modulating human mesenchymal stem cells using poly(Eta-butyl acrylate) networks in vitro with elasticity matching human arteries %U %X %0 conference lecture %@ %A Maier, A., Braune, S., Kratz, K., Latour, R.A., Lendlein, A., Jung, F. %D 2018 %J 37. Jahrestagung der Deutschen Gesellschaft fuer Klinische Mikrozirkulation und Haemorheologie, DGKMH 2018 %T Adsorption and conformation of von Willebrand factor from fresh human plasma on to polymer-based biomaterials %U %X %0 conference poster %@ %A Wang, W., Xu, X., Li, Z., Kratz, K., Ma, N., Lendlein, A. %D 2018 %J Advanced Functional Polymers for Medicine, AFPM 2018 %T Tuning polymer elasticity to regulate human mesenchymal stem cells: a potential strategy for tissue-engineering of blood vessels %U %X %0 conference poster %@ %A Gould, O., Lysyakova, L., Kratz, K., Lendlein, A. %D 2018 %J Advanced Functional Polymers for Medicine, AFPM 2018 %T Quantification of Shape Memory Nano/microfibers by Atomic Force Microscopy %U %X %0 conference poster %@ %A Heuchel, M., Weigel, T., Kratz, K., Lendlein, A. %D 2018 %J International Biotech Innovation Days %T Morphological analysis of porous poly(ether imide) microparticles by mercury porosimetry %U %X %0 conference poster %@ %A Noechel, U., Behl, M., Kratz, K., Lendlein, A. %D 2018 %J Advanced Functional Polymers for Medicine, AFPM 2018 %T Tailoring the Thermo-Mechanical Properties of Degradable Copolyetherester Urethanes Comprising Oligo(p-dioxanone) and Oligo(e-caprolactone) segments %U %X %0 conference lecture %@ %A Kuhnla, A., Braune, S., Baeckemo-Johannsson, J., Maier, A., Reinthaler, M., Landmesser, U., Lendlein, A., Jung, F. %D 2018 %J 37. Jahrestagung der Deutschen Gesellschaft fuer Klinische Mikrozirkulation und Haemorheologie, DGKMH 2018 %T In vitro hemocompatibility testing of left atrial appendage occlusion device %U %X %0 journal article %@ 2059-8521 %A Farhan, M., Rudolph, T., Kratz, K., Lendlein, A. %D 2018 %J MRS Advances %N 63 %P 3861-3868 %R doi:10.1557/adv.2018.621 %T Torsional Fiber Actuators from Shape-memory Polymer %U https://doi.org/10.1557/adv.2018.621 63 %X Humanoid robots, prosthetic limbs and exoskeletons require soft actuators to perform their primary function, which is controlled movement. In this work, we explored whether crosslinked poly[ethylene-co-(vinyl acetate)] (cPEVA) fibers, with different vinyl acetate (VA) content can serve as torsional fiber actuators, exhibiting temperature controlled reversible rotational changes. Broad melting transitions ranging from 50 to 90 °C for cPEVA18-165 or from 40 to 80 °C for cPEVA28-165 fibers in combination with complete crystallization at temperatures around 10 °C make them suitable actuating materials with adjustable actuation temperature ranges between 10 and 70 °C during repetitive cooling and heating. The obtained fibers exhibited a circular cross section with diameters around 0.4±0.1 mm, while a length of 4 cm was employed for the investigation of reversible rotational actuation after programming by twist insertion using 30 complete rotations at a temperature above melting transition. Repetitive heating and cooling between 10 to 60 °C or 70 °C of one-end-tethered programmed fibers revealed reversible rotations and torsional force. During cooling 3±1 complete rotations (Δθr = + 1080±360°) in twisting direction were observed, while 4±1 turns in the opposite direction (Δθr = - 1440±360°) were found during heating. Such torsional fiber actuators, which are capable of approximately one rotation per cm fiber length, can serve as miniaturized rotary motors to provide rotational actuation in futuristic humanoid robots. %0 conference lecture %@ %A Schoene, A.-C., Schulz, B., Lendlein, A. %D 2018 %J 17th International Conference on Organized Molecular Films, ICOMF %T Effects of enzymes on biomaterial surfaces evaluated by Langmuir Monolayer Techniques %U %X %0 conference lecture %@ %A Lendlein, A. %D 2018 %J Tag der offenen Tuer %T Herzlich Willkommemn am HZG Campus Teltow-Seehof %U %X %0 conference lecture %@ %A Lendlein, A. %D 2018 %J Kooperation in der Gesundheitswirtschaft - Wegbereiter fuer Innovation, Workshop %T Willkommen am HZG Campus Teltow, Institut fuer Biomaterialforschung %U %X %0 conference lecture %@ %A Benner, S., Schroeter, M., Lendlein, A. %D 2018 %J Sitzung des Arbeitskreis Schule & Wirtschaft des Landkreises Potsdam-Mittelmark %T Das Institut fuer Biomaterialforschung der HZG in Teltow %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2018 %J Berufsorientierung fuer Schueler am Industriemuseum Teltow %T Forschung bei HZG – Polymere in der Medizin %U %X %0 journal article %@ 0002-8703 %A Reinthaler, M., Ozga, A.-K., Sinning, D., Curio, J., Al-Hindwan, H.S., Baeckemo-Johansson, J., Jung, F., Lendlein, A., Rauch, G., Landmesser, U. %D 2018 %J American Heart Journal %P 95-102 %R doi:10.1016/j.ahj.2018.03.025 %T Revival of transcatheter PFO closure: A meta-analysis of randomized controlled trials - impact of shunt size and age %U https://doi.org/10.1016/j.ahj.2018.03.025 %X According to our meta-analysis TPC plus antiplatelets was superior in terms of stroke prevention when compared to Med-Tx. Furthermore, patients with moderate to severe shunts and those younger than 45 years of age were found to benefit most from TPC. %0 journal article %@ 2059-8521 %A Razzaq, M.Y., Behl, M., Lendlein, A. %D 2018 %J MRS Advances %N 63 %P 3783-3791 %R doi:10.1557/adv.2018.613 %T Thermally-Induced Actuation of Magnetic Nanocomposites Based on Oligo(Omega-Pentadecalactone) and Covalently Integrated Magnetic Nanoparticles %U https://doi.org/10.1557/adv.2018.613 63 %X The incorporation of inorganic particles in a polymer matrix has been established as a method to adjust the mechanical performance of composite materials. We report on the influence of covalent integration of magnetic nanoparticles (MNP) on the actuation behavior and mechanical performance of hybrid nanocomposite (H-NC) based shape-memory polymer actuators (SMPA). The H-NC were synthesized by reacting two types of oligo(ω-pentadecalactone) (OPDL) based precursors with terminal hydroxy groups, a three arm OPDL (3AOPDL, Mn = 6000 g mol·1-1) and an OPDL (Mn =3300 g · mol-1) coated magnetite nanoparticle (Ø = 10 ± 2 nm), with a diisocyanate. These H-NC were compared to the homopolymer network regarding the actuation performance, contractual stress (σcontr) as well as thermal and mechanical properties. The melting range of the OPDL crystals (ΔTm,OPDL) was shifted in homo polymer networks from 36 °C – 76 °C to 41°C – 81 °C for H-NC with 9 wt% of MNP content. The actuators were explored by variation of separating temperature (Tsep), which splits the OPDL crystalline domain into actuating and geometry determining segments. Tsep was varied in the melting range of the nanocomposites and the actuation capability and contractual stress (σcontr) of the nanocomposite actuators could be adjusted. The reversible strain (εrev) was decreased from 11 ± 0.3% for homo polymer network to 3.2±0.3% for H-NC9 with 9 wt% of MNP indicating a restraining effect of the MNP on chain mobility. The results show that the performance of H-NCs in terms of thermal and elastic properties can be tailored by MNP content, however for higher reversible actuation, lower MNP contents are preferable. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J 15th European Symposium on Controlled Drug Delivery, ESCDD 2018 %T Design of block copolymers for multifunctional carriers %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J 4th International Conference on Biomedical Polymers and Polymeric Biomaterials, ISBPPB 2018 %T Implementing multifunctionality in polymeric biomaterials for medical applications %U %X %0 conference lecture %@ %A Schulz, B., Schoene, A.-C., Ihlenburg, R.B.J., Raschdorf, E., Lendlein, A. %D 2018 %J 17th International Conference on Organized Molecular Films, ICOMF %T Interfacial behavior of oligodepsipeptides at aqueous surfaces %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J CIB-CSIC Meeting %T Shape-memory polymers and actuators %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J 27th International Materials Research Congress %T Re-programmable shape-memory polymer actuators %U %X %0 journal article %@ 0168-3659 %A Ceylan Tuncaboylu, D., Friess, F., Wischke, C., Lendlein, A. %D 2018 %J Journal of Controlled Release %P 240-247 %R doi:10.1016/j.jconrel.2018.06.022 %T A multifunctional multimaterial system for on-demand protein release %U https://doi.org/10.1016/j.jconrel.2018.06.022 %X In order to provide best control of the regeneration process for each individual patient, the release of protein drugs administered during surgery may need to be timely adapted and/or delayed according to the progress of healing/regeneration. This study aims to establish a multifunctional implant system for a local on-demand release, which is applicable for various types of proteins. It was hypothesized that a tubular multimaterial container kit, which hosts the protein of interest as a solution or gel formulation, would enable on-demand release if equipped with the capacity of diameter reduction upon external stimulation. Using devices from poly(ɛ-caprolactone) networks, it could be demonstrated that a shape-memory effect activated by heat or NIR light enabled on-demand tube shrinkage. The decrease of diameter of these shape-memory tubes (SMT) allowed expelling the payload as demonstrated for several proteins including SDF-1α, a therapeutically relevant chemotactic protein, to achieve e.g. continuous release with a triggered add-on dosing (open tube) or an on-demand onset of bolus or sustained release (sealed tube). Considering the clinical relevance of protein factors in (stem) cell attraction to lesions and the progress in monitoring biomarkers in body fluids, such on-demand release systems may be further explored e.g. in heart, nerve, or bone regeneration in the future. %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2018 %J Girls and Boys Day - Zukunftstag fuer Maedchen und Jungen 2018 %T Forschung bei HZG - Polymere in der Medizin %U %X %0 conference poster %@ %A Schroeter, M., Lendlein, A. %D 2018 %J Potsdamer Tag der Wissenschaften 2018 %T Biologisch Abbaubare Kunststoffe %U %X %0 conference lecture %@ %A Lendlein, A., Neffe, A.T. %D 2018 %J 2nd International Conference on Dermal Delivery by Nanocarriers: Highlights from SFB 1112, Abschlusscolloquium %T Depsipeptides - An innovative nanocarrier system %U %X %0 conference lecture %@ %A Schroeter, M., Schulz, B., Lendlein, A. %D 2018 %J Potsdamer Tag der Wissenschaften 2018 %T Biologisch abbaubare Kunststoffe – Forschen fuer die Zukunft %U %X %0 conference lecture %@ %A Gould, O., Lysyakova, L., Kratz, K., Lendlein, A. %D 2018 %J XXVII Int. Materials Research Congress (IMRC) 2018 %T Implementing and Quantifying the Shape-Memory Effect of Single Polymeric Micro/Nanowires with an Atomic Force Microscope %U %X %0 conference lecture %@ %A Deng, Z., Nie, Y., Wang, W., Ma, N., Lendlein, A. %D 2018 %J 37. Jahrestagung der Deutschen Gesellschaft fuer Klinische Mikrozirkulation und Haemorheologie, DGKMH 2018 %T Dedifferentiation of mature adipocytes with cold cycling %U %X %0 conference lecture %@ %A Kuhnla, A., Reinthaler, M., Braune, S., Maier, A., Pindur, G., Lendlein, A., Jung, F. %D 2018 %J Joint Conference of Three Societies: European Society of Clinical Hemorheology and Miclrocirculation, International Society of Biorheology, International Society of Clinical Hemorheology, ESCHM-ISB-ISCH 2018 %T Spontaneous and induced platelet aggregation in apparently healthy subjects in relation to age %U %X %0 conference lecture (invited) %@ %A Wischke, C., Lendlein, A. %D 2018 %J Gesundheitswissenschaften - Perspektiven in der Lausitz, Workshop %T Interdisziplinaere Grundlagenforschung fuer eine altersgerechte Medizin %U %X %0 conference poster %@ %A Bhuvanesh, T., Machatschek, R., Schulz, B., Nie, Y., Ma, N., Lendlein, A. %D 2018 %J Joint Conference of Three Societies: European Society of Clinical Hemorheology and Miclrocirculation, International Society of Biorheology, International Society of Clinical Hemorheology, ESCHM-ISB-ISCH 2018 %T A facile way to archive biomimetic laminin networks on substrates %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2018 %J Berufsorientierung am Vicco-von-Buelow Gymnasium %T Biomaterialforschung bei HZG, Perspektiven fuer die Zukunft %U %X %0 conference lecture %@ %A Schroeter, M., Lach, L., Lendlein, A. %D 2018 %J Tag der Wissenschaften am Weinberg-Gymnasium %T Chemie ist nicht nur wenn es knallt und stinkt! Intelligente Kunststoffe, Chemische Stimuli und deren Anwendung %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J 7th International Congress of Biomaterials, BIOMAT 2018 %T Designing polymeric biomaterials to instruct cells by physical cues %U %X %0 journal article %@ 0024-9297 %A Yan, W., Rudolph, T., Noechel, U., Gould, O., Behl, M., Kratz, K., Lendlein, A. %D 2018 %J Macromolecules %N 12 %P 4624-4632 %R doi:10.1021/acs.macromol.8b00322 %T Reversible Actuation of Thermoplastic Multiblock Copolymers with Overlapping Thermal Transitions of Crystalline and Glassy Domains %U https://doi.org/10.1021/acs.macromol.8b00322 12 %X Polymeric materials possessing specific features like programmability, high deformability, and easy processability are highly desirable for creating modern actuating systems. In this study, thermoplastic shape-memory polymer actuators obtained by combining crystallizable poly(ε-caprolactone) (PCL) and poly(3S-isobutylmorpholin-2,5-dione) (PIBMD) segments in multiblock copolymers are described. We designed these materials according to our hypothesis that the confinement of glassy PIBMD domains present at the upper actuation temperature contribute to the stability of the actuator skeleton, especially at large programming strains. The copolymers have a phase-segregated morphology, indicated by the well-separated melting and glass transition temperatures for PIBMD and PCL, but possess a partially overlapping Tm of PCL and Tg of PIBMD in the temperature interval from 40 to 60 °C. Crystalline PIBMD hard domains act as strong physical netpoints in the PIBMD−PCL bulk material enabling high deformability (up to 2000%) and good elastic recoverability (up to 80% at 50 °C above Tm,PCL). In the programmed thermoplastic actuators a high content of crystallizable PCL actuation domains ensures pronounced thermoreversible shape changes upon repetitive cooling and heating. The programmed actuator skeleton, composed of PCL crystals present at the upper actuation temperature Thigh and the remaining glassy PIBMD domains, enabled oriented crystallization upon cooling. The actuation performance of PIBMD-PCL could be tailored by balancing the interplay between actuation and skeleton, but also by varying the quantity of crystalline PIBMD hard domains via the copolymer composition, the applied programming strain, and the choice of Thigh. The actuator with 17 mol% PIBMD showed the highest reversible elongation of 11.4% when programmed to a strain of 900% at 50 °C. It is anticipated that the presented thermoplastic actuator materials can be applied as modern compression textiles. %0 journal article %@ 2470-9476 %A Lendlein, A. %D 2018 %J Science Robotics %N 18 %P eaat9090 %R doi:10.1126/scirobotics.aat9090 %T Fabrication of reprogrammable shape-memory polymer actuators for robotics %U https://doi.org/10.1126/scirobotics.aat9090 18 %X Shape-memory polymer actuators, whose actuation geometry and switching temperatures are reprogrammable by physical fabrication schemes, were recently suggested for robotics with the option for self-healing and degradability. %0 journal article %@ 1386-0291 %A Krueger-Genge, A., Schulz, C., Kratz, K., Lendlein, A., Jung, F. %D 2018 %J Clinical Hemorheology and Microcirculation %N 3 %P 437-445 %R doi:10.3233/CH-189904 %T Comparison of two substrate materials used as negative control in endothelialization studies: Glass versus polymeric tissue culture plate %U https://doi.org/10.3233/CH-189904 3 %X In conclusion, these findings indicate that both reference materials are almost comparable and can be used equivalently as control materials in in vitro endothelialization studies. %0 journal article %@ 2073-4360 %A Farhan, M., Rudolph, T., Noechel, U., Kratz, K., Lendlein, A. %D 2018 %J Polymers %N 3 %P 255 %R doi:10.3390/polym10030255 %T Extractable Free Polymer Chains Enhance Actuation Performance of Crystallizable Poly(Epsilon-caprolactone) Networks and Enable Self-Healing %U https://doi.org/10.3390/polym10030255 3 %X Crosslinking of thermoplastics is a versatile method to create crystallizable polymer networks, which are of high interest for shape-memory actuators. Here, crosslinked poly(ε-caprolactone) thermosets (cPCLs) were prepared from linear starting material, whereby the amount of extractable polymer was varied. Fractions of 5–60 wt % of non-crosslinked polymer chains, which freely interpenetrate the crosslinked network, were achieved leading to differences in the resulting phase of the bulk material. This can be described as “sponge-like” with open or closed compartments depending on the amount of interpenetrating polymer. The crosslinking density and the average network chain length remained in a similar range for all network structures, while the theoretical accessible volume for reptation of the free polymer content is affected. This feature could influence or introduce new functions into the material created by thermomechanical treatment. The effect of interpenetrating PCL in cPCLs on the reversible actuation was analyzed by cyclic, uniaxial tensile tests. Here, high reversible strains of up to ∆ε = 24% showed the enhanced actuation performance of networks with a non-crosslinked PCL content of 30 wt % resulting from the crystal formation in the phase of the non-crosslinked PCL and co-crystallization with network structures. Additional functionalities are reprogrammability and self-healing capabilities for networks with high contents of extractable polymer enabling reusability and providing durable actuator materials. %0 conference lecture %@ %A Braune, S., Xourida, M., Maier, A., Kratz, K., Latour, B., Lendlein, A., Jung, F. %D 2018 %J 37. Jahrestagung der Deutschen Gesellschaft fuer Klinische Mikrozirkulation und Haemorheologie, DGKMH 2018 %T Translocation and release of von Willebrand factor in platelets adherent on polymer-based biomaterial surfaces %U %X %0 journal article %@ 1439-4235 %A Fang, L., Gould, O.E.C., Lysyakova, L., Jiang, Y., Sauter, T., Frank, O., Becker, T., Schossig, M., Kratz, K., Lendlein, A. %D 2018 %J ChemPhysChem %N 16 %P 2078-2084 %R doi:10.1002/cphc.201701362 %T Implementing and Quantifying the Shape-Memory Effect of Single Polymeric Micro/Nanowires with an Atomic Force Microscope %U https://doi.org/10.1002/cphc.201701362 16 %X The implementation of shape‐memory effects (SME) in polymeric micro‐ or nano‐objects currently relies on the application of indirect macroscopic manipulation techniques, for example, stretchable molds or phantoms, to ensembles of small objects. Here, we introduce a method capable of the controlled manipulation and SME quantification of individual micro‐ and nano‐objects in analogy to macroscopic thermomechanical test procedures. An atomic force microscope was utilized to address individual electro‐spun poly(ether urethane) (PEU) micro‐ or nanowires freely suspended between two micropillars on a micro‐structured silicon substrate. In this way, programming strains of 10±1% or 21±1% were realized, which could be successfully fixed. An almost complete restoration of the original free‐suspended shape during heating confirmed the excellent shape‐memory performance of the PEU wires. Apparent recovery stresses of σmax,app=1.2±0.1 and 33.3±0.1 MPa were obtained for a single microwire and nanowire, respectively. The universal AFM test platform described here enables the implementation and quantification of a thermomechanically induced function for individual polymeric micro‐ and nanosystems. %0 conference lecture %@ %A Papagrigorakes, M., Chirico, N., Blocki, A., Neffe, A.T., Jung, F., Ma, N., Lendlein, A. %D 2018 %J Joint Conference of Three Societies: European Society of Clinical Hemorheology and Miclrocirculation, International Society of Biorheology, International Society of Clinical Hemorheology, ESCHM-ISB-ISCH 2018 %T AD-MSCS change their morphology and secretion profile as a response to changes in substrates`elastic properties in combination with inflammatory stimuli %U %X %0 conference lecture %@ %A Wischke, C., Baehr, E., Racheva, M., Heuchel, M., Weigel, T., Lendlein, A. %D 2018 %J 27th International Materials Research Congress %T Surface immobilization strategies for tyrosinase as biocatalyst applicable to polymer network synthesis %U %X %0 journal article %@ 2059-8521 %A Wischke, C., Baehr, E., Racheva, M., Heuchel, M., Weigel, T., Lendlein, A. %D 2018 %J MRS Advances %N 63 %P 3875-3881 %R doi:10.1557/adv.2018.630 %T Surface immobilization strategies for tyrosinase as biocatalyst applicable to polymer network synthesis %U https://doi.org/10.1557/adv.2018.630 63 %X Enzymes have recently attracted increasing attention in material research based on their capacity to catalyze the conversion of polymer-bound moieties for synthesizing polymer networks, particularly bulk hydrogels. In this study, the surface immobilization of a relevant enzyme, mushroom tyrosinase, should be explored using glass as model surface. In a first step, the glass support was functionalized with silanes to introduce either amine or carboxyl groups, as confirmed e.g. by X-ray photoelectron spectroscopy. By applying glutaraldehyde and EDC/NHS chemistry, respectively, surfaces have been activated for subsequent successful coupling of tyrosinase. Via protein hydrolysis and amino acid characterization by HPLC, the quantity of bound tyrosinase was shown to correspond to a full surface coverage. Based on the visualized enzymatic conversion of a test substrate at the glass support, the functionalized surfaces may be explored for surface-associated material synthesis in the future. %0 journal article %@ 1386-0291 %A Kumar, R.K., Heuchel, M., Kratz, K., Lendlein, A., Jankowski, J., Tetali, S.D. %D 2018 %J Clinical Hemorheology and Microcirculation %N 1-2 %P 175-185 %R doi:10.3233/CH-189112 %T Effects of extracts prepared from modified porous poly(ether imide) microparticulate absorbers on cytotoxicity, macrophage differentiation and proinflammatory behavior of human monocytic (THP-1) cells %U https://doi.org/10.3233/CH-189112 1-2 %X Remaining uremic toxins in the blood of chronic renal failure patients represent one central challenge in hemodialysis therapies. Highly porous poly(ether imide) (PEI) microparticles have been recently introduced as candidate absorber materials, which show a high absorption capacity for uremic toxins and allow hydrophilic surface modification suitable for minimization of serum protein absorption. In this work, the effects of extracts prepared from PEI microparticles modified by nucleophilic reaction with low molecular weight polyethylene imine (Pei) or potassium hydroxide (KOH), on human monocytic (THP-1) cells are studied. The obtained results suggested that the extracts of Pei and KOH modified PEI absorbers have no negative effect on THP-1 cell viability and do not initiate the critical differentiation towards macrophages. The extracts did not enhance transcript or protein levels of investigated proinflammatory markers in THP-1 cells, namely, TNFμ, MCP1, IL6 and IL8. Based on these findings such modified PEI microparticles should be qualified for further pre-clinical evaluation i.e. in an in vivo animal experiment. %0 journal article %@ 2051-6347 %A Wang, L., Razzaq, M.Y., Rudolph, T., Heuchel, M., Noechel, U., Mansfeld, U., Jiang, Y., Gould, O.E.C., Behl, M., Kratz, K., Lendlein, A. %D 2018 %J Materials Horizons %N 5 %P 861-867 %R doi:10.1039/C8MH00266E %T Reprogrammable, magnetically controlled polymeric nanocomposite actuators %U https://doi.org/10.1039/C8MH00266E 5 %X Soft robots and devices with the advanced capability to perform adaptive motions similar to that of human beings often have stimuli-sensitive polymeric materials as the key actuating component. The external signals triggering the smart polymers’ actuations can be transmitted either via a direct physical connection between actuator and controlling unit (tethered) or remotely without a connecting wire. However, the vast majority of such polymeric actuator materials are limited to one specific type of motion as their geometrical information is chemically fixed. Here, we present magnetically driven nanocomposite actuators, which can be reversibly reprogrammed to different actuation geometries by a solely physical procedure. Our approach is based on nanocomposite materials comprising spatially segregated crystallizable actuation and geometry determining units. Upon exposure to a specific magnetic field strength the actuators’ geometric memory is erased by the melting of the geometry determining units allowing the implementation of a new actuator shape. The actuation performance of the nanocomposites can be tuned and the technical significance was demonstrated in a multi-cyclic experiment with several hundreds of repetitive free-standing shape shifts without losing performance. %0 book part %@ %A Braune, S., Lendlein, A., Jung, F. %D 2018 %J Hemocompatibility of Biomaterials for Clinical Applications, Blood-Biomaterials Interactions %P 51-76 %R doi:10.1016/B978-0-08-100497-5.00004-5 %T Developing standards and test protocols for testing the hemocompatibility of biomaterials %U https://doi.org/10.1016/B978-0-08-100497-5.00004-5 %X In this chapter, we have emphasized that the standards given by regulatory institutions, such as the ASTM or the ISO norm committee, describe only minimum requirements for studying the thrombogenicity and hemocompatibility of biomaterials. As a consequence, it is still under debate as to which supplementary assays need to be performed to enhance our understanding of the processes at the blood-material interface and to improve the hemocompatibility of new materials for blood-contacting implants. Test for the evaluation of thrombogenicity and hemocompatibility should at least be selected according to the categories formulated in the ISO norm: platelet adhesion and activation, coagulation, thrombosis, hematology, and immunology. In an ideal testing scenario, the selection of all above mentioned parameters should enable a comprehensive interstudy and interlaboratory comparison for different tested materials. Formulation of appropriate standards that allow reproducible testing and harmonized categorization of biomaterials should be consequently approached as a common consensus not just of the regulatory but also of the scientific community as it is already realized in the clinical chemistry and hematology. %0 journal article %@ 1386-0291 %A Hiebl, B., Ascher, L., Luetzow, K., Kratz, K., Gruber, C., Mrowietz, C., Nehring, M.E., Lendlein, A., Franke, R.-P., Jung, F. %D 2018 %J Clinical Hemorheology and Microcirculation %N 1-2 %P 317-326 %R doi:10.3233/CH-189108 %T Albumin solder covalently bound to a polymer membrane: New approach to improve binding strength in laser tissue soldering in-vitro %U https://doi.org/10.3233/CH-189108 1-2 %X Laser tissue soldering (LTS) based on indocyanine green (ICG)-mediated heat-denaturation of proteins might be a promising alternative technique for micro-suturing, but up to now the problem of too weak shear strength of the solder welds in comparison to sutures is not solved. Earlier reports gave promising results showing that solder supported by carrier materials can enhance the cohesive strength of the liquid solder. In these studies, the solder was applied to the carriers by dip coating. Higher reliability of the connection between the solder and the carrier material is expected when the solder is bound covalently to the carrier material. In the present study a poly(ether imide) (PEI) membrane served as carrier material and ICG-supplemented albumin as solder substrate. The latter was covalently coupled to the carrier membrane under physiological conditions to prevent structural protein changes. As laser source a diode continuous-wave laser emitting at 808 nm with intensities between 250 mW and 1500 mW was utilized. The albumin functionalized carrier membrane was placed onto the tunica media of explanted pig thoracic aortae forming an overlapping area of approximately 0.5×0.5 cm2. All tests were performed in a dry state to prevent laser light absorption by water. Infrared spectroscopy, spectro-photometrical determination of the secondary and primary amine groups after acid orange II staining, contact angle measurements, and atomic force microscopy proved the successful functionalization of the PEI membrane with albumin. A laser power of 450 mW LTS could generate a membrane-blood vessel connection which was characterized by a shear strength of 0.08±0.002 MPa, corresponding to 15% of the tensile strength of the native blood vessel. Theoretically, an overlapping zone of 4.1 mm around the entire circumference of the blood vessel could have provided shear strength of the PEI membrane-blood vessel compound identical to the tensile strength of the native blood vessel. These in-vitro results confirmed the beneficial effects of solder reinforcement by carrier membranes, and suggest LTS with covalently bound solders on PEI substrates for further studies in animal models. %0 journal article %@ 1386-0291 %A Krueger-Genge, A., Steinbrecht, S., Kuepper, J.-H., Lendlein, A., Jung, F. %D 2018 %J Clinical Hemorheology and Microcirculation %N 1-2 %P 267-276 %R doi:10.3233/CH-189125 %T Evidence for cytostatic effect of cyclophosphamide on human vein endothelial cells in cancer therapy: Preliminary in vitro results %U https://doi.org/10.3233/CH-189125 1-2 %X These results are in agreement with clinical events like thromboses in patients in compromised condition under therapy with CPA, as the detachment of EC might induce responses of circulating platelets leading to the adherence and aggregation with the risk of the formation of thrombi. Whether CPA acts directly or via toxic metabolites on EC will be examined in more detail in following studies. %0 conference lecture %@ %A Lendlein, A. %D 2018 %J Italian Institute of Technology %T Introduction to Helmholtz Association, Helmholtz-Zentrum Geesthacht and Call for Helmholtz International Labs %U %X %0 journal article %@ 1386-0291 %A Krueger-Genge, A., Braune, S., Walter, M., Krengel, M., Kratz, K., Kuepper, J.-H., Lendlein, A., Jung, F. %D 2018 %J Clinical Hemorheology and Microcirculation %N 1-2 %P 305-316 %R doi:10.3233/CH-189130 %T Influence of different surface treatments of poly(Eta-butyl acrylate) networks on fibroblasts adhesion, morphology and viability %U https://doi.org/10.3233/CH-189130 1-2 %X The applied surface treatments of cPnBA successfully improved the adhesion of viable fibroblasts. Under resting conditions as well as after shearing the highest fibroblast densities were found on surfaces with combined post-treatment. %0 journal article %@ 1386-0291 %A Al-Hindwan, H.S.A., Landmesser, U., Staehli, B., Alushi, B., Curio, J., Neumann, T., Jung, F., Lendlein, A., Jacobs, S., Reinthaler, M. %D 2018 %J Clinical Hemorheology and Microcirculation %N 1 %P 15-25 %R doi:10.3233/CH-189906 %T The predictive value of a modified Carpentier classification in patients with coincidental mitral regurgitation undergoing TAVI for severe aortic valve stenosis %U https://doi.org/10.3233/CH-189906 1 %X In conclusion, despite significant MR regression in all MR groups, some individuals may require additional mitralvalve repair after TAVI. According to our data the timing of these procedures should be based on the underlying MR etiology. The Carpentier classification in patients with coincidental MR undergoing TAVI for severe AS may also have prognostic implications as we found an increased incidence of strokes in our LA functional cohort and a worse mortality rates in organic MR. %0 conference lecture %@ %A Kratz, K., Liu, Y., Rudolph, T., Lendlein, A. %D 2018 %J ProcessNet-Jahrestagung und 33. DECHEMA-Jahrestagung der Biotechnologen 2018 %T Einfluss von Deformations- und Separationstemperatur auf das Formgedaechtnisverhalten von polymeren Mikroquadern %U %X %0 journal article %@ 0009-286X %A Kratz, K., Liu, Y., Rudolph, T., Lendlein, A. %D 2018 %J Chemie - Ingenieur - Technik %N 9 %P 1331-1332 %R doi:10.1002/cite.201855431 %T Einfluss von Deformations- und Separationstemperatur auf das Formgedaechtnisverhalten von polymeren Mikroquadern %U https://doi.org/10.1002/cite.201855431 9 %X No abstract %0 conference lecture %@ %A Wischke, C., Baehr, E., Racheva, M., Lendlein, A. %D 2018 %J ProcessNet-Jahrestagung und 33. DECHEMA-Jahrestagung der Biotechnologen 2018 %T Tyrosinase als Biokatalysator: Synthese von Hydrogelen und Oberflaechenfunktionalisierung %U %X %0 journal article %@ 0009-286X %A Wischke, C., Baehr, E., Racheva, M., Lendlein, A. %D 2018 %J Chemie - Ingenieur - Technik %N 9 %P 1292 %R doi:10.1002/cite.201855348 %T Tyrosinase als Biokatalysator: Synthese von Hydrogelen und Oberflaechenfunktionalisierung %U https://doi.org/10.1002/cite.201855348 9 %X No abstract %0 editorial %@ 2399-7532 %A Lendlein, A., Trask, R.S. %D 2018 %J Multifunctional Materials %N 1 %P 010201 %R doi:10.1088/2399-7532/aada7b %T Editorial: Multifunctional materials: concepts, function-structure relationships, knowledge-based design, translational materials research %U https://doi.org/10.1088/2399-7532/aada7b 1 %X Integrating different functions in one material system is a fundamental challenge, especially if those functions seem to exclude each other. Understanding function-structure relationships and developing a competence in the system approach for multifunctionality enables many modern applications, which can improve quality of life and address important global challenges. The interdisciplinary field recently extends to computational engineering approaches for virtual material design and to advanced fabrication schemes taking advantage of digitalisation. In this way development cycles can be shortened and products based on multifunctional materials can become more and more adaptive and individualised. It is against this backdrop that Multifunctional Materials has been launched, in consultation with the scientific community, to become a selective journal focused on conceptual novelty that will uniquely bring together all aspects of this rapidly developing field. %0 editorial %@ 1439-4235 %A Lendlein, A., Feng, Y., Grijpma, D.W., Zhao, Y. %D 2018 %J ChemPhysChem %N 16 %P 1938-1940 %R doi:10.1002/cphc.201800578 %T Smart Materials %U https://doi.org/10.1002/cphc.201800578 16 %X No abstract %0 conference lecture %@ %A Kuhnla, A., Baeckemo-Johansson, J., Maier, A., Reinthaler, M., Landmesser, U., Lendlein, A., Jung, F. %D 2018 %J 37. Jahrestagung Deutsche Gesellschaft fuer Klinische Mikrozirkulation und Haemorheologie %T In vitro hemocompatibility testing of left atrial appendage occlusion devices %U %X %0 journal article %@ 2059-8521 %A Machatschek, R., Schulz, B., Lendlein, A. %D 2018 %J MRS Advances %N 63 %P 3883-3889 %R doi:10.1557/adv.2018.602 %T The influence of pH on the molecular degradation mechanism of PLGA %U https://doi.org/10.1557/adv.2018.602 63 %X Poly[(rac-lactide)-co-glycolide] (PLGA) is used in medicine to provide mechanical support for healing tissue or as matrix for controlled drug release. The properties of this copolymer depend on the evolution of the molecular weight of the material during degradation, which is determined by the kinetics of the cleavage of hydrolysable bonds. The generally accepted description of the degradation of PLGA is a random fragmentation that is autocatalyzed by the accumulation of acidic fragments inside the bulk material. Since mechanistic studies with lactide oligomers have concluded a chain-end scission mechanism and monolayer degradation experiments with polylactide found no accelerated degradation at lower pH, we hypothesize that the impact of acidic fragments on the molecular degradation kinetics of PLGA is overestimated. By means of the Langmuir monolayer degradation technique, the molecular degradation kinetics of PLGA at different pH could be determined. Protons did not catalyze the degradation of PLGA. The molecular mechanism at neutral pH and low pH is a combination of random and chainend-cut events, while the degradation under strongly alkaline conditions is determined by rapid chainend cuts. We suggest that the degradation of bulk PLGA is not catalyzed by the acidic degradation products. Instead, increased concentration of small fragments leads to accelerated mass loss via fast chain-end cut events. In the future, we aim to substantiate the proposed molecular degradation mechanism of PLGA with interfacial rheology. %0 journal article %@ 2059-8521 %A Yan, W., Fang, L., Noechel, U., Gould, O.E.C., Behl, M., Kratz, K., Lendlein, A. %D 2018 %J MRS Advances %N 63 %P 3741-3749 %R doi:10.1557/adv.2018.590 %T Investigating the Roles of Crystallizable and Glassy Switching Segments within Multiblock Copolymer Shape-Memory Materials %U https://doi.org/10.1557/adv.2018.590 63 %X The variation of the molecular architecture of multiblock copolymers has enabled the introduction of functional behaviour and the control of key mechanical properties. In the current study, we explore the synergistic relationship of two structural components in a shape-memory material formed of a multiblock copolymer with crystallizable poly(ε-caprolactone) and crystallizable poly[oligo(3S-iso-butylmorpholine-2,5-dione)] segments (PCL-PIBMD). The thermal and structural properties of PCL-PIBMD films were compared with PCL-PU and PIBMD-PU, investigated by means of DSC, SAXS and WAXS measurements. The shape-memory properties were quantified by cyclic, thermomechanical tensile tests, where deformation strains up to 900% were applied for programming PCL-PIBMD films at 50 °C. Toluene vapor treatment experiments demonstrated that the temporary shape was fixed mainly by glassy PIBMD domains at strains lower than 600%, with the PCL contribution to fixation increasing to 42±2% at programming strains of 900%. This study into the shape-memory mechanism of PCL-PIBMD provides insight into the structure-function relation in multiblock copolymers with both crystallizable and glassy switching segments. %0 conference lecture %@ %A Krueger-Genge, A., Dietze, S., Yan, W., Liu, Y., Fang, L., Kratz, K., Lendlein, A., Jung, F. %D 2018 %J 37. Jahrestagung Deutsche Gesellschaft fuer Klinische Mikrozirkulation und Haemorheologie %T Endothelial cell migration, adhesion and proliferation on different polymeric substrates %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J Materials Science for Medical Robotics, Workshop Hamlyn Symposium 2018 %T Shape-memory polymer actuators for soft robotics %U %X %0 conference lecture %@ %A Farhan, M., Rudolph, T., Kratz, K., Lendlein, A. %D 2018 %J XXVII Int. Materials Research Congress (IMRC) 2018 %T Non-continuously responding polymeric actuators %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J International Symposium on stimuli responsive materials 2018 %T Shape-memory polymer actuators %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2018 %J Tag der Wissenschaften 2018 am Weinberg Gymnasium %T Chemie ist nicht nur; wenn es knallt und stinkt! Intelligente Kunststoffe %U %X %0 journal article %@ 1616-5187 %A Peng, X., Behl, M., Zhang, P., Mazurek-Budzyñska, M., Feng, Y., Lendlein, A. %D 2018 %J Macromolecular Bioscience %N 12 %P 1800257 %R doi:10.1002/mabi.201800257 %T Synthesis of Well-Defined Dihydroxy Telechelics by (Co)polymerization of Morpholine-2,5-Diones Catalyzed by Sn(IV) Alkoxide %U https://doi.org/10.1002/mabi.201800257 12 %X Well-defined dihydroxy telechelic oligodepsipeptides (oDPs), which have a high application potential as building blocks for scaffold materials for tissue engineering applications or particulate carrier systems for drug delivery applications are synthesized by ring-opening polymerization (ROP) of morpholine-2,5-diones (MDs) catalyzed by 1,1,6,6-tetra-n-butyl-1,6-distanna-2,5,7,10-tetraoxacyclodecane (Sn(IV) alkoxide). In contrast to ROP catalyzed by Sn(Oct)2, the usage of Sn(IV) alkoxide leads to oDPs, with less side products and well-defined end groups, which is crucial for potential pharmaceutical applications. A slightly faster reaction of the ROP catalyzed by Sn(IV) alkoxide compared to the ROP initiated by Sn(Oct)2/EG is found. Copolymerization of different MDs resulted in amorphous copolymers with T gs between 44 and 54 °C depending on the molar comonomer ratios in the range from 25% to 75%. Based on the well-defined telechelic character of the Sn(IV) alkoxide synthesized oDPs as determined by matrix-assisted laser desorption/ionization time of flight measurements, they resemble interesting building blocks for subsequent postfunctionalization or multifunctional materials based on multiblock copolymer systems whereas the amorphous oDP-based copolymers are interesting building blocks for matrices of drug delivery systems. %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2018 %J Marie-Curie Tag 2018 %T Kunststoffe in der Medizin - Neue Entwicklungen %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J MRS Fall Meeting 2018 %T Multifunctional biomaterials containing amino acid based segments for tissue regeneration and efficient transfection of primary human cells %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J MRS Fall Meeting 2018 %T Reprogrammable Shape-Memory Polymer Actuators for Robotics %U %X %0 conference lecture %@ %A Jiang, Y., Mansfeld, U., Fang, L., Kratz, K., Lendlein, A. %D 2018 %J XXVII Int. Materials Research Congress (IMRC) 2018 %T Multilevel topographical changes of polymeric surfaces control their aerophobic behavior %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J Conference on Functional Polymers for Human Health %T Shape-Memory Polymers and Actuators in Health Technologies %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J Lecture at the Department of Biomedical Engineering at the Southern University of Science and Technology %T Shape-memory Polymers – from one way shape recovery to reversible actuation %U %X behavior are explained and potential applications are outlined. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2018 %J Shape-Memory Applications; Research and Technology 2018 %T Shape-memory polymer actuators %U %X %0 journal article %@ 0014-3057 %A Piluso, S., Vukicevic, R., Noechel, U., Braune, S., Lendlein, A., Neffe, A. %D 2018 %J European Polymer Journal %P 77-85 %R doi:10.1016/j.eurpolymj.2018.01.017 %T Sequential alkyne-azide cycloadditions for functionalized gelatin hydrogel formation %U https://doi.org/10.1016/j.eurpolymj.2018.01.017 %X While click chemistry reactions for biopolymer network formation are attractive as the defined reactions may allow good control of the network formation and enable subsequent functionalization, tailoring of gelatin network properties over a wide range of mechanical properties has yet to be shown. Here, it is demonstrated that copper-catalyzed alkyne-azide cycloaddition of alkyne functionalized gelatin with diazides gave hydrogel networks with properties tailorable by the ratio of diazide to gelatin and diazide rigidity. 4,4′-diazido-2,2′-stilbenedisulfonic acid, which has been used as rigid crosslinker, yielded hydrogels with Young’s moduli E of 50–390 kPa and swelling degrees Q of 150–250 vol.%, while the more flexible 1,8-diazidooctane resulted in hydrogels with E = 125–280 kPa and Q = 225–470 vol.%. Storage moduli could be varied by two orders of magnitude (G′ = 100–20,000 Pa). An indirect cytotoxicity test did not show cytotoxic properties. Even when employing 1:1 ratios of alkyne and azide moieties, the hydrogels were shown to contain both, unreacted alkyne groups on the gelatin backbone as well as dangling chains carrying azide groups as shown by reaction with functionalized fluorescein. The free groups, which can be tailored by the employed ratio of the reactants, are accessible for covalent attachment of drugs, as was demonstrated by functionalization with dexamethasone. The sequential network formation and functionalization with click chemistry allows access to multifunctional materials relevant for medical applications. %0 journal article %@ 1742-7061 %A Sarem, M., Arya, N., Heizmann, M., Neffe, A., Barbero, A., Gebauer, T., Martin, I., Lendlein, A., Shastri, V. %D 2018 %J Acta Biomaterialia %P 83-94 %R doi:10.1016/j.actbio.2018.01.025 %T Interplay between stiffness and degradation of architectured gelatin hydrogels leads to differential modulation of chondrogenesis in vitro and in vivo %U https://doi.org/10.1016/j.actbio.2018.01.025 %X The limited capacity of cartilage to heal large lesions through endogenous mechanisms has led to extensive effort to develop materials to facilitate chondrogenesis. Although physical-chemical properties of biomaterials have been shown to impact in vitro chondrogenesis, whether these findings are translatable in vivo is subject of debate. Herein, architectured 3D hydrogel scaffolds (ArcGel) (produced by crosslinking gelatin with ethyl lysine diisocyanate (LDI)) were used as a model system to investigate the interplay between scaffold mechanical properties and degradation on matrix deposition by human articular chondrocytes (HAC) from healthy donors in vitro and in vivo. Using ArcGel scaffolds of different tensile and shear modulus, and degradation behavior; in this study, we compared the fate of ex vivo engineered ArcGels-chondrocytes constructs, i.e. the traditional tissue engineering approach, with the de novo formation of cartilaginous tissue in HAC laden ArcGels in an ectopic nude mouse model. While the softer and fast degrading ArcGel (LNCO3) was more efficient at promoting chondrogenic differentiation in vitro, upon ectopic implantation, the stiffer and slow degrading ArcGel (LNCO8) was superior in maintaining chondrogenic phenotype in HAC and retention of cartilaginous matrix. Furthermore, surprisingly the de novo formation of cartilage tissue was promoted only in LNCO8. Since HAC cultured for only three days in the LNCO8 environment showed upregulation of hypoxia-associated genes, this suggests a potential role for hypoxia in the observed in vivo outcomes. In summary, this study sheds light on how immediate environment (in vivo versus in vitro) can significantly impact the outcomes of cell-laden biomaterials. %0 book part %@ %A Lendlein, A., Razzaq, M.Y., Wischke, C., Kratz, K., Heuchel, M., Zotzmann, J., Hiebl, B., Neffe, A.T., Behl, M. %D 2017 %J Comprehensive Biomaterials II - Reference Module in Materials Science and Materials Engineering, Metallic, Ceramic, and Polymeric Biomaterials %P 620-647 %R doi:10.1016/B978-0-12-803581-8.10213-9 %T Shape-Memory Polymers %U https://doi.org/10.1016/B978-0-12-803581-8.10213-9 %X Medical devices such as implants, surgical instruments, extracorporal devices, and wound covers, as well as controlled drug delivery systems (CDDS) require a specific combination of material properties and functions including, for example, mechanical stability, biocompatibility, and biofunctionality. Polymeric biomaterials are of high relevance for such applications, as properties and functions can be tuned in a wide range by only small defined variations of their chemical or morphological structure. The rapid progress in surgical techniques, especially in minimally invasive surgery, requires smart materials, which are capable of an active on-demand movement and which do not need to be removed in a second surgery. These challenges can be addressed by shape-memory polymers (SMPs) described in this chapter. SMPs are of high technological significance for biomedical applications as they enable on-demand predefined changes in the shape of a device upon exposure to a suitable stimulus such as heat or alternating magnetic field (AMF). Multifunctional materials are obtained when the shape-memory effect is combined with an additional function such as hydrolytic degradability, biofunctionality, and controlled drug release. Selected biomaterials with shape-memory capability are presented, including data on their biocompatibility. The potential of SMPs as a platform technology for biomedical applications is sketched by an overview on SMP-based medical devices being developed and the potential use of SMPs as matrix for CDDS. %0 lecture %@ %A Lendlein, A., Schroeter, M., Schulz, B., Neffe, A.T. %D 2017 %J %T Wahlpflicht Polymerchemie – Anwendungen in der Medizin Resorbierbare Polymere %U %X %0 lecture %@ %A Lendlein, A., Schroeter, M. %D 2017 %J %T Applied biomaterials, implants, polymers, scaffolds, gels in 3D - Introduction BSRT %U %X %0 conference lecture %@ %A Krueger-Genge, A., Hiebl, B., Franke, R.P., Lendlein, A., Jung, F. %D 2017 %J 36th Conference of the German Society for Clinical Microcirculation and Hemorheology %T Effects of Tacrolimus or Sirolimus on the adhesion of vascular wall cells: Controlled in-vitro comparison study %U %X %0 journal article %@ 1042-7147 %A Balk, M., Grijpma, D.W., Lendlein, A. %D 2017 %J Polymers for Advanced Technologies %N 10 %P 1203-1205 %R doi:10.1002/pat.3980 %T Design and processing of advanced functional polymers for medicine %U https://doi.org/10.1002/pat.3980 10 %X No abstract %0 journal article %@ 0939-6411 %A Brunacci, N., Wischke, C., Naolou, T., Neffe, A.T., Lendlein, A. %D 2017 %J European Journal of Pharmaceutics and Biopharmaceutics %P 61-65 %R doi:10.1016/j.ejpb.2016.11.011 %T Influence of surfactants on depsipeptide submicron particle formation %U https://doi.org/10.1016/j.ejpb.2016.11.011 %X Surfactants are required for the formation and stabilization of hydrophobic polymeric particles in aqueous environment. In order to form submicron particles of varying sizes from oligo[3-(S)-sec-butylmorpholine-2,5-dione]diols ((OBMD)-diol), different surfactants were investigated. As new surfactants, four-armed star-shaped oligo(ethylene glycol)s of molecular weights of 5–20 kDa functionalized with desamino-tyrosine (sOEG-DAT) resulted in smaller particles with lower PDI than with desaminotyrosyl tyrosine (sOEG-DATT) in an emulsion/solvent evaporation method. In a second set of experiments, sOEG-DAT of Mn = 10 kDa was compared with the commonly employed emulsifiers polyvinylalcohol (PVA), polyoxyethylene (20) sorbitan monolaurate (Tween 20), and D-α-tocopherol polyethylene glycol succinate (VIT E-TPGS) for OBMD particle preparation. sOEG-DAT allowed to systematically change sizes in a range of 300 up to 900 nm with narrow polydispersity, while in the other cases, a lower size range (250–400 nm, PVA; ∼300 nm, Tween 20) or no effective particle formation was observed. The ability of tailoring particle size in a broad range makes sOEG-DAT of particular interest for the formation of oligodepsipeptide particles, which can further be investigated as drug carriers for controlled delivery. %0 conference lecture %@ %A Braune, S., Bäckemo Johansson, J., Reinthaler, M., Landmesser, U., Lendlein, A., Jung, F. %D 2017 %J 36. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheologie (DGKMH) %T Effects of anticoagulants on blood cell interactions with polymers %U %X %0 editorial %@ 0939-6411 %A Naolou, T., Ruehl, E., Lendlein, A. %D 2017 %J European Journal of Pharmaceutics and Biopharmaceutics %P 1-3 %R doi:10.1016/j.ejpb.2017.03.004 %T Editorial: Nanocarriers: Architecture, transport, and topical application of drugs for therapeutic use %U https://doi.org/10.1016/j.ejpb.2017.03.004 %X No abstract %0 journal article %@ 0001-4842 %A Löwenberg, C., Balk, M., Wischke, C., Behl, M., Lendlein, A. %D 2017 %J Accounts of Chemical Research %N 4 %P 723-732 %R doi:10.1021/acs.accounts.6b00584 %T Shape-Memory Hydrogels: Evolution of Structural Principles To Enable Shape Switching of Hydrophilic Polymer Networks %U https://doi.org/10.1021/acs.accounts.6b00584 4 %X In this Account, the principles of hydrogel network design, incorporation of molecular switches, and hydrogel microstructures are summarized that enable a spatially directed actuation of hydrogels by a shape-memory effect (SME) without major volume alteration. The SME involves an elastic deformation (programming) of samples, which are temporarily fixed by reversible covalent or physical cross-links resulting in a temporary shape. The material can reverse to the original shape when these molecular switches are affected by application of a suitable stimulus. Hydrophobic shape-memory polymers (SMPs), which are established with complex functions including multiple or reversible shape-switching, may provide inspiration for the molecular architecture of shape-memory hydrogels (SMHs), but cannot be identically copied in the world of hydrophilic soft materials. For instance, fixation of the temporary shape requires cross-links to be formed also in an aqueous environment, which may not be realized, for example, by crystalline domains from the hydrophilic main chains as these may dissolve in presence of water. Accordingly, dual-shape hydrogels have evolved, where, for example, hydrophobic crystallizable side chains have been linked into hydrophilic polymer networks to act as temperature-sensitive temporary cross-links. By incorporating a second type of such side chains, triple-shape hydrogels can be realized. Considering the typically given light permeability of hydrogels and the fully hydrated state with easy permeation by small molecules, other types of stimuli like light, pH, or ions can be employed that may not be easily used in hydrophobic SMPs. In some cases, those molecular switches can respond to more than one stimulus, thus increasing the number of opportunities to induce actuation of these synthetic hydrogels. Beyond this, biopolymer-based hydrogels can be equipped with a shape switching function when facilitating, for example, triple helix formation in proteins or ionic interactions in polysaccharides. Eventually, microstructured SMHs such as hybrid or porous structures can combine the shape-switching function with an improved performance by helping to overcome frequent shortcomings of hydrogels such as low mechanical strength or volume change upon temporary cross-link cleavage. Specifically, shape switching without major volume alteration is possible in porous SMHs by decoupling small volume changes of pore walls on the microscale and the macroscopic sample size. Furthermore, oligomeric rather than short aliphatic side chains as molecular switches allow stabilization of the sample volumes. Based on those structural principles and switching functionalities, SMHs have already entered into applications as soft actuators and are considered, for example, for cell manipulation in biomedicine. In the context of those applications, switching kinetics, switching forces, and reversibility of switching are aspects to be further explored. %0 journal article %@ 1022-1336 %A Chen, D., Xia, X., Wong, T.W., Bai, H., Behl, M., Zhao, Q., Lendlein, A., Xie, T. %D 2017 %J Macromolecular Rapid Communications %N 7 %P 1600746 %R doi:10.1002/marc.201600746 %T Omnidirectional Shape Memory Effect via Lyophilization of PEG Hydrogels %U https://doi.org/10.1002/marc.201600746 7 %X Device applications of shape memory polymers demand diverse shape changing geometries, which are currently limited to non-omnidirectional movement. This restriction originates from traditional thermomechanical programming methods such as uniaxial, biaxial stretching, bending, or compression. A solvent-modulated programming method is reported to achieve an omnidirectional shape memory behavior. The method utilizes freeze drying of hydrogels of polyethylene glycol networks with a melting transition temperature around 50 °C in their dry state. Such a process creates temporarily fixed macroporosity, which collapses upon heating, leading to significant omnidirectional shrinkage. These shrunken materials can swell in water to form hydrogels again and the omnidirectional programming and recovery can be repeated. The fixity ratio (R f) and recovery ratio (R r) can be maintained at 90% and 98% respectively upon shape memory multicycling. The maximum linear recoverable strain, as limited by the maximum swelling, is ≈90%. Amongst various application potentials, one can envision the fabrication of multiphase composites by taking advantages of the omnidirectional shrinkage from a porous polymer to a denser structure. %0 journal article %@ 1042-7147 %A Piluso, S., Lendlein, A., Neffe, A.T. %D 2017 %J Polymers for Advanced Technologies %N 10 %P 1318-1324 %R doi:10.1002/pat.3962 %T Enzymatic action as switch of bulk to surface degradation of clicked gelatin-based networks %U https://doi.org/10.1002/pat.3962 10 %X Polymer degradation occurs under physiological conditions in vitro and in vivo, especially when bonds susceptible to hydrolysis are present in the polymer. Understanding of the degradation mechanism, changes of material properties over time, and overall rate of degradation is a necessary prerequisite for the knowledge-based design of polymers with applications in biomedicine. Here, hydrolytic degradation studies of gelatin-based networks synthesized by copper-catalyzed azide-alkyne cycloaddition reaction are reported, which were performed with or without addition of an enzyme. In all cases, networks with a stilbene as crosslinker proofed to be more resistant to degradation than when an octyl diazide was used. Without addition of an enzyme, the rate of degradation was ruled by the crosslinking density of the network and proceeded via a bulk degradation mechanism. Addition of Clostridium histolyticum collagenase resulted in a much enhanced rate of degradation, which furthermore occurred via surface erosion. The mesh size of the hydrogels (>7 nm) was in all cases larger than the hydrodynamic radius of the enzyme (4.5 nm) so that even in very hydrophilic networks with large mesh size enzymes may be used to induce a fast surface degradation mechanism. This observation is of general interest when designing hydrogels to be applied in the presence of enzymes, as the degradation mechanism and material performance are closely interlinked. %0 conference lecture %@ %A Zou, J., Wang, W., Neffe, A.T., Xu, X., Li, Z., Deng, Z., Sun, X. Ma, N., Lendlein, A. %D 2017 %J 36th Conference of the German Society for Clinical Microcirculation and Hemorheology %T Adipogenic differentiation of human adipose derived mesenchymal stem cells in 3D architectured gelatin based hydrogels (ArcGel) %U %X %0 journal article %@ 2192-2640 %A Braune, S., Latour, R.A., Lendlein, A., Jung, F. %D 2017 %J Advanced Healthcare Materials %N 17 %P 1700294 %R doi:10.1002/adhm.201700294 %T Comment on: “Hemocompatibility of Superhemophobic Titania Surfaces” %U https://doi.org/10.1002/adhm.201700294 17 %X No abstract %0 journal article %@ 0939-6411 %A Zhang, N., Said, A., Wischke, C., Kral, V., Brodwolf, R., Volz, P., Boreham, A., Gerecke, C., Li, W., Neffe, A.T., Kleuser, B., Alexiev, U., Lendlein, A., Schaefer-Korting, M. %D 2017 %J European Journal of Pharmaceutics and Biopharmaceutics %P 66-75 %R doi:10.1016/j.ejpb.2016.10.019 %T Poly[acrylonitrile-co-(N-vinyl pyrrolidone)] nanoparticles – Composition-dependent skin penetration enhancement of a dye probe and biocompatibility %U https://doi.org/10.1016/j.ejpb.2016.10.019 %X Nanoparticles can improve topical drug delivery: size, surface properties and flexibility of polymer nanoparticles are defining its interaction with the skin. Only few studies have explored skin penetration for one series of structurally related polymer particles with systematic alteration of material composition. Here, a series of rigid poly[acrylonitrile-co-(N-vinyl pyrrolidone)] model nanoparticles stably loaded with Nile Red or Rhodamin B, respectively, was comprehensively studied for biocompatibility and functionality. Surface properties were altered by varying the molar content of hydrophilic NVP from 0 to 24.1% and particle size ranged from 35 to 244 nm. Whereas irritancy and genotoxicity were not revealed, lipophilic and hydrophilic nanoparticles taken up by keratinocytes affected cell viability. Skin absorption of the particles into viable skin ex vivo was studied using Nile Red as fluorescent probe. Whilst an intact stratum corneum efficiently prevented penetration, almost complete removal of the horny layer allowed nanoparticles of smaller size and hydrophilic particles to penetrate into viable epidermis and dermis. %0 lecture %@ %A Lendlein, A., Schroeter, M. %D 2017 %J %T Polymere in der Medizin %U %X %0 conference lecture %@ %A Kratz, K., Liu, Y., Jiang, Y., Fang, L., Lendlein, A. %D 2017 %J MRS Spring Meeting; Symposium SM8 %T Characterizing shape-memory effects of polymeric micro-scale objects %U %X %0 conference lecture %@ %A Liu, Y., Razzaq, M., Rudolph, T., Kratz, K., Lendlein, A. %D 2017 %J BIFTM PhD Symposium - BioInterfaces in Technology and Medicine %T Two-level shape changes of polymeric microcuboids prepared from crystallizable copolymer networks %U %X %0 conference poster %@ %A Zhang, Q., Kratz, K., Lendlein, A. %D 2017 %J XXVI International Materials Research Congress (IMRC) 2017; Symp. F4: Shape-memory and self-repairing materials %T Reversible bidirectional shape-memory properties of electrospun fibrous meshes %U %X %0 conference poster %@ %A Altabal, O., Wischke, C., Lendlein, A. %D 2017 %J XXVI International Materials Research Congress (IMRC) 2017; Symp. F4: Shape-memory and self-repairing materials %T Controlled deformation of polymer substrates with negative poisson ratio %U %X %0 conference lecture %@ %A Blocki, A., Loeper, F., Chirico, N., Neffe, A.T., Jung, F., Stamm, C., Lendlein, A. %D 2017 %J 36th Conference of the German Society for Clinical Microcirculation and Hemorheology %T Engineering of cell-laden gelatin-based microcapsules for cell delivery and immobilization in regenerative therapies %U %X %0 journal article %@ 1525-7797 %A Wang, W., Naolou, T., Ma, N., Deng, Z., Xu, X., Mansfeld, U., Wischke, C., Gossen, M., Neffe, A.T., Lendlein, A. %D 2017 %J Biomacromolecules %N 11 %P 3819-3833 %R doi:10.1021/acs.biomac.7b01034 %T Polydepsipeptide Block-Stabilized Polyplexes for Efficient Transfection of Primary Human Cells %U https://doi.org/10.1021/acs.biomac.7b01034 11 %X The rational design of a polyplex gene carrier aims to balance maximal effectiveness of nucleic acid transfection into cells with minimal adverse effects. Depsipeptide blocks with an Mn ∼ 5 kDa exhibiting strong physical interactions were conjugated with PEI moieties (2.5 or 10 kDa) to di- and triblock copolymers. Upon nanoparticle formation and complexation with DNA, the resulting polyplexes (sizes typically 60–150 nm) showed remarkable stability compared to PEI-only or lipoplex and facilitated efficient gene delivery. Intracellular trafficking was visualized by observing fluorescence-labeled pDNA and highlighted the effective cytoplasmic uptake of polyplexes and release of DNA to the perinuclear space. Specifically, a triblock copolymer with a middle depsipeptide block and two 10 kDa PEI swallowtail structures mediated the highest levels of transgenic VEGF secretion in mesenchymal stem cells with low cytotoxicity. These nanocarriers form the basis for a delivery platform technology, especially for gene transfer to primary human cells. %0 conference lecture %@ %A Farhan, M., Kratz, K., Lendlein, A. %D 2017 %J MRS Spring Meeting 2017; Symposium SM8 %T Reversible shape-memory effect of crosslinked thermoplastic polymer blends %U %X %0 conference lecture %@ %A Razzaq, M., Behl, M., Lendlein, A. %D 2017 %J MRS Spring Meeting 2017 %T Thermally-induced reversible bidirectional shape-memory effect of hybrid nanocomposites %U %X %0 conference lecture %@ %A Krüger-Genge, A., Hauser, S., Neffe, A., Pietzsch, J., Lendlein, A., Jung, F. %D 2017 %J 36. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheologie (DGKMH) %T Endothelialisation of gelatin- based hydrogels with different elasticity and degradation time %U %X %0 conference lecture %@ %A Blocki, A., Löper, F., Chirico, N., Neffe, A., Jung, F., Stamm, C., Lendlein, A. %D 2017 %J 36. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheologie %T Engineering of cell-laden gelatin-based microcapsules for cell delivery and immobilization in cell-based regenerative therapies %U %X %0 journal article %@ 1386-0291 %A Wang, W., Li, W., Wang, J., Hu, Q., Balk, M., Bieback, K., Stamm, C., Jung, F., Tang, G., Lendlein, A., Ma, N. %D 2017 %J Clinical Hemorheology and Microcirculation %N 3-4 %P 279-295 %R doi:10.3233/CH-179209 %T Folate receptor mediated genetic modification of human mesenchymal stem cells via folic acid-polyethylenimine-grafted poly(N-3-hydroxypropyl)aspartamide %U https://doi.org/10.3233/CH-179209 3-4 %X Mesenchymal stem cells (MSCs) are targeted as vehicles for cell mediated gene therapy. Here we report on a macromolecular carrier, which was designed aiming at successful targeted gene delivery into MSCs through the mediation of folate receptor and reduced cytotoxicity compared to established cationic polymer vector – polyethylenimine with a weight average molecular weight (Mw) of 25,000 Dalton (PEI25K). The carrier PHPA-PEI1800-FA was synthesized in a two-step procedure. PHPA-PEI1800 was prepared by grafting polyethylenimine with a Mw of 1800 Dalton (PEI1800) onto the α,β-poly(N-3-hydroxypropyl)-D,L-aspartamide (PHPA) backbone. PHPA-PEI1800-FA was obtained by chemically conjugating folic acid onto PHPA-PEI1800. The grafting degree of PEI1800 was 3.9±0.2% in relation to the CH groups of PHPA and the molar ratio of folic acid conjugated to PEI1800 (χFA) was 1.8±0.1 as calculated by NMR spectroscopy. The copolymers were biodegradable and exhibited lower cytotoxicity than PEI25K. Compared to PHPA-PEI1800, PHPA-PEI1800-FA led to a significantly higher transfection efficiency in human MSCs, which could be attributed to the mediation of folate receptor during the transfection process as confirmed by folic acid competition assay. Both marker gene (GFP) and therapeutic gene (VEGF) were delivered into human MSCs from multi-donors using PHPA-PEI1800-FA. The percentage of GFP+ MSCs showed an average value of 2.85±1.60% but a large variation for different samples. The VEGF expression level of the PHPA-PEI1800-FA transfected cells was significantly higher than that of either untransfected or naked DNA transfected cells. Conclusively, PHPA-PEI1800-FA is a suitable vector to deliver genes into human MSCs through the interaction with folate receptor. %0 conference lecture %@ %A Li, Z., Xu, X., Wang, W., Kratz, K., Sun, X., Zou, J., Deng, Z., Jung, F., Gossen, M., Ma, N., Lendlein, A. %D 2017 %J 36. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheologie (DGKMH) %T Preconditioning with topographic microstructure of materials promotes the migration capacity of adipose derived mesenchymal stem cells %U %X transplantation of topographic microstructure preconditioned stem cells. %0 conference lecture %@ %A Li, Z., Xu, X., Wang, W., Kratz, K., Sun, X., Zou, J., Deng, Z., Jung, F., Gossen, M., Ma, N., Lendlein, A. %D 2017 %J 36th Conference of the German Society for Clinical Microcirculation and Hemorheology %T Modulation of the mesenchymal stem cell migration capacity via preconditioning with topographic microstructure %U %X %0 journal article %@ 1386-0291 %A Li, Z., Xu, X., Wang, W., Kratz, K., Sun, X., Zou, J., Deng, Z., Jung, F., Gossen, M., Ma, N., Lendlein, A. %D 2017 %J Clinical Hemorheology and Microcirculation %N 3-4 %P 267-278 %R doi:10.3233/CH-179208 %T Modulation of the mesenchymal stem cell migration capacity via preconditioning with topographic microstructure %U https://doi.org/10.3233/CH-179208 3-4 %X Controlling mesenchymal stem cells (MSCs) behavior is necessary to fully exploit their therapeutic potential. Various approaches are employed to effectively influence the migration capacity of MSCs. Here, topographic microstructures with different microscale roughness were created on polystyrene (PS) culture vessel surfaces as a feasible physical preconditioning strategy to modulate MSC migration. By analyzing trajectories of cells migrating after reseeding, we demonstrated that the mobilization velocity of human adipose derived mesenchymal stem cells (hADSCs) could be promoted by and persisted after brief preconditioning with the appropriate microtopography. Moreover, the elevated activation levels of focal adhesion kinase (FAK) and mitogen-activated protein kinase (MAPK) in hADSCs were also observed during and after the preconditioning process. These findings underline the potential enhancement of in vivo therapeutic efficacy in regenerative medicine via transplantation of topographic microstructure preconditioned stem cells. %0 journal article %@ 2050-750X %A Li, Z., Wang, W., Xu, X., Kratz, K., Zou, J., Lysyakova, L., Heuchel, M., Kurtz, A., Gossen, M., Ma, N., Lendlein, A. %D 2017 %J Journal of Materials Chemistry B %N 35 %P 7415-7425 %R doi:10.1039/C7TB01232B %T Integrin β1 activation by micro-scale curvature promotes pro-angiogenic secretion of human mesenchymal stem cells %U https://doi.org/10.1039/C7TB01232B 35 %X Fine tuning of the substrate properties to modulate the function of mesenchymal stem cells (MSCs) has emerged as an attractive strategy to optimize their therapeutic potential. In the context of the mechanotransduction process, the conformational change of integrin (integrin activation) plays a critical role in perceiving and transmitting various signals. In this study, polymeric cell culture inserts with defined bottom roughness were fabricated as a model system for cell cultivation. We showed that the conformational change of integrin and its downstream signaling cascade of human adipose-derived mesenchymal stem cells (hADSCs) could be modulated by the curvature of the cell–material interface. The curvature of the substrate surface with a roughness in the size range of a single cell could strongly increase the high-affinity β1 integrin level of hADSCs without alteration of the total β1 integrin level. Further, the integrin downstream FAK/ERK and Rho/ROCK pathways were activated and resulted in upregulated VEGF secretion of hADSCs. A conditioned medium on such a surface exhibited a strong pro-angiogenic effect, with an increased formation of the tubular structure, a higher migration velocity of endothelial cells and an enhanced blood vessel density in an ex vivo hen's egg test-chorioallantoic membrane (HET-CAM). These results highlighted the clinical potential to manipulate the topographic features of the cell culture substrate, whereby to regulate integrin affinity states and further control MSC functions. %0 journal article %@ 2059-8521 %A Xu, X., Wang, W., Li, Z., Kratz, K., Ma, N., Lendlein, A. %D 2017 %J MRS Advances %N 47 %P 2561-2570 %R doi:10.1557/adv.2017.487 %T Microwell Geometry Modulates Interleukin-6 Secretion in Human Mesenchymal Stem Cells %U https://doi.org/10.1557/adv.2017.487 47 %X The therapeutic effect of mesenchymal stem cells (MSCs) has been investigated in various clinical applications, in which their functional benefits are mainly attributed to the secretion of soluble factors. The enhancement of their therapeutic potential by physical and chemical properties of cell culture substrate is a safe and effective strategy, since they are highly sensitive to their microenvironment such as the elasticity and surface topography. In this study, we demonstrated that the geometry of polymeric substrate regulated the interleukin-6 (IL-6) secretion of human adipose derived MSCs. Polystyrene substrates comprising arrays of square-shaped (S50) or round-shaped (R50) microwells (side length or diameter of 50 μm and depth of 10 μm) were prepared by injection molding. Cellular apoptototic rate of MSCs was not affected by the microwell geometry, while the upregulated secretion of IL-6 and the enhancement of nuclear transcription factor STAT3 were detected in MSCs seeded on S50 substrate. The geometry-dependent modulatory effect was highly associated with ROCK signaling cascade. The inhibition of ROCK abolished the disparity in IL-6 secretion. These findings highlight the possibility to steer the secretion profile of stem cells via microwell geometry in combination with the manipulation of ROCK signaling pathway. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2017 %J Polymers for Advanced Technologies Conference %T Enabling Alternative Stimuli in Shape-memory Polymers %U %X %0 journal article %@ 1944-8244 %A Farhan, M., Rudolph, T., Noechel, U., Yan, W., Kratz, K., Lendlein, A. %D 2017 %J ACS Applied Materials and Interfaces %N 39 %P 33559-33564 %R doi:10.1021/acsami.7b11316 %T Noncontinuously Responding Polymeric Actuators %U https://doi.org/10.1021/acsami.7b11316 39 %X Reversible movements of current polymeric actuators stem from the continuous response to signals from a controlling unit, and subsequently cannot be interrupted without stopping or eliminating the input trigger. Here, we present actuators based on cross-linked blends of two crystallizable polymers capable of pausing their movements in a defined manner upon continuous cyclic heating and cooling. This noncontinuous actuation can be adjusted by varying the applied heating and cooling rates. The feasibility of these devices for technological applications was shown in a 140 cycle experiment of free-standing noncontinuous shape shifts, as well as by various demonstrators. %0 journal article %@ 1042-7147 %A Bhuvanesh, T., Saretia, S., Roch, T., Schoene, A.-C., Rottke, F.O., Kratz, K., Wang, W., Ma, N., Schulz, B., Lendlein, A. %D 2017 %J Polymers for Advanced Technologies %N 10 %P 1305-1311 %R doi:10.1002/pat.3910 %T Langmuir–Schaefer films of fibronectin as designed biointerfaces for culturing stem cells %U https://doi.org/10.1002/pat.3910 10 %X Glycoproteins adsorbing on an implant upon contact with body fluids can affect the biological response in vitro and in vivo, depending on the type and conformation of the adsorbed biomacromolecules. However, this process is poorly characterized and so far not controllable. Here, protein monolayers of high molecular cohesion with defined density are transferred onto polymeric substrates by the Langmuir–Schaefer (LS) technique and were compared with solution deposition (SO) method. It is hypothesized that on polydimethylsiloxane (PDMS), a substrate with poor cell adhesion capacity, the fibronectin (FN) layers generated by the LS and SO methods will differ in their organization, subsequently facilitating differential stem cell adhesion behavior. Indeed, atomic force microscopy visualization and immunofluorescence images indicated that organization of the FN layer immobilized on PDMS was uniform and homogeneous. In contrast, FN deposited by SO method was rather heterogeneous with appearance of structures resembling protein aggregates. Human mesenchymal stem cells showed reduced absolute numbers of adherent cells, and the vinculin expression seemed to be higher and more homogenously distributed after seeding on PDMS equipped with FN by LS in comparison with PDMS equipped with FN by SO. These divergent responses could be attributed to differences in the availability of adhesion molecule ligands such as the Arg-Gly-Asp (RGD) peptide sequence presented at the interface. The LS method allows to control the protein layer characteristics, including the thickness and the protein orientation or conformation, which can be harnessed to direct stem cell responses to defined outcomes, including migration and differentiation. %0 journal article %@ 1381-5148 %A Ceylan Tuncaboylu, D., Wischke, C., Stoermann, F., Lendlein, A. %D 2017 %J Reactive and Functional Polymers %P 68-73 %R doi:10.1016/j.reactfunctpolym.2016.12.015 %T Microgels from microfluidic templating and photoinduced crosslinking of cinnamylidene acetic acid modified precursors %U https://doi.org/10.1016/j.reactfunctpolym.2016.12.015 %X So far, a number of approaches to synthesize microgel networks have been followed, while only in few cases a detailed control of the network architecture has been possible. Here, the photoinduced [2 + 2] cycloaddition reaction of cinnamylidene acetic acid (CAA) moieties coupled to four-arm star shaped oligo(ethylene glycol) (OEG) precursors was explored for the creation of microgels with defined polymer network structures. Based on a rational solvent selection and precursor dispersion in glass-capillary microfluidics, microgels could be successfully prepared by the proposed synthesis approach. Model reactions confirmed a quantitative network formation. Therefore, compared to common radical polymerization for microgel crosslinking, CAA-dimerization may be an alternative approach particularly when well defined network structures are desired. %0 journal article %@ 1042-7147 %A Yan, W., Fang, L., Weigel, T., Behl, M., Kratz, K., Lendlein, A. %D 2017 %J Polymers for Advanced Technologies %N 10 %P 1339-1345 %R doi:10.1002/pat.3953 %T The influence of thermal treatment on the morphology in differently prepared films of a oligodepsipeptide based multiblock copolymer %U https://doi.org/10.1002/pat.3953 10 %X In this study, we explored the influence of applying different thermal treatments on the resulting morphologies of solution-cast and spin-coated PCL-PIBMD thin films, which showed different initial surface morphologies. Differential scanning calorimetry results and atomic force microscopy images after different thermal treatments indicated that PCL and PIBMD domains showed similar crystallization behaviors in 270 ± 30 µm thick solution-cast films as well as in 30 ± 2 and 8 ± 1 nm thick spin-coated PCL-PIBMD films. Existing PIBMD crystalline domains highly restricted the generation of PCL crystalline domains during cooling when the sample was annealed at 180 °C. By annealing the sample above 120 °C, the PIBMD domains crystallized sufficiently and covered the free surface, which restricted the crystallization of PCL domains during cooling. The PCL domains can crystallize by hindering the crystallization of PIBMD domains via the fast vitrification of PIBMD domains when the sample was cooled/quenched in liquid nitrogen after annealing at 180 °C. These findings contribute to a better fundamental understanding of the crystallization mechanism of multi-block copolymers containing two crystallizable domains whereby the Tg of the higher melting domain type is in the same temperature range as the Tm of the lower melting domain type. %0 journal article %@ 1860-7314 %A Roch, T., Hahne, S., Kratz, K., Ma, N., Lendlein, A. %D 2017 %J Biotechnology Journal %N 12 %P 1700334 %R doi:10.1002/biot.201700334 %T Transparent Substrates Prepared From Different Amorphous Polymers Can Directly Modulate Primary Human B cell functions %U https://doi.org/10.1002/biot.201700334 12 %X Manipulation of B cell functions such as antibody and cytokine secretion, is of clinical and biotechnological interest and can be achieved by soluble ligands activating cell surface receptors. Alternatively, the exposure to suitable solid substrates would offer the possibility to transiently induced cell signaling, since the signaling is interrupted when the cells are removed from the substrate. Cell/substrate interactions are mediated by physical valences such as, hydrogen bonds or hydrophobic forces on the substrate surface. Therefore, in this study B cells were cultivated on polymeric substrates, differing in their chemical composition and thus their capacity to undergo physical interactions. Activated B cells cultivated on polystyrene (PS) showed an altered cytokine response indicated by increased IL-10 and decreased IL-6 secretion. Interestingly, B cells cultivated on polyetherurethane (PEU), which has among all tested polymers the highest potential to form strong hydrogen bonds showed an impaired activation, which could be restored by re-cultivation on tissue culture polystyrene. The results indicate that B cell behavior can transiently be manipulated solely by interacting with polymeric surface, which could be explained by receptor activation mediated by physical interaction with the substrate or by altering the availability of the soluble stimulatory reagents by adsorption processes. %0 journal article %@ 0024-9297 %A Liu, Y., Razzaq, M.Y., Rudolph, T., Fang, L., Kratz, K., Lendlein, A. %D 2017 %J Macromolecules %N 6 %P 2518-2527 %R doi:10.1021/acs.macromol.6b02237 %T Two-Level Shape Changes of Polymeric Microcuboids Prepared from Crystallizable Copolymer Networks %U https://doi.org/10.1021/acs.macromol.6b02237 6 %X Polymeric microdevices bearing features like nonspherical shapes or spatially segregated surface properties are of increasing importance in biological and medical analysis, drug delivery, and bioimaging or microfluidic systems as well as in micromechanics, sensors, information storage, or data carrier devices. Here, a method to fabricate programmable microcuboids with shape-memory capability and the quantification of their recovery at different levels is reported. The method uses the soft lithographic technique to create microcuboids with well-defined sizes and surface properties. Microcuboids having an edge length of 25 μm and a height of 10 μm were prepared from cross-linked poly[ethylene-co-(vinyl acetate)] (cPEVA) with different vinyl acetate contents and were programmed by compression with various deformation degrees at elevated temperatures. The microlevel shape-recovery of the cuboidal geometry during heating was monitored by optical microscopy (OM) and atomic force microscopy (AFM) studying the related changes in the projected area (PA) or height, while the nanolevel changes of the nanosurface roughness were investigated by in situ AFM. The shape-memory effect at the microlevel was quantified by the recovery ratio of cuboids (Rr,micro), while at the nanolevel, the recovery ratio of the nanoroughness (Rr,nano) was measured. The values of Rr,micro could be tailored in a range from 42 ± 1% to 102 ± 1% and Rr,nano from 89 ± 6% to 136 ± 21% depending on the applied compression ratio and the amount of vinyl acetate content in the cPEVA microcuboids. %0 conference poster %@ %A Assuncao, M., Walter, M., Bäckemo Johansson, J., Topczewska, P., Krüger-Genge, A., Braune, S., Roch, T., Blocki, A., Behl, M., Jannasch, A., Matschke, K., Klopfleisch, R., Jung, F., Lendlein, A. %D 2017 %J 36. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheologie (DGKMH) %T Characterization of PCL-BA copolymer networks for application as vascular patch %U %X %0 journal article %@ 1042-7147 %A Heuchel, M., Gerber, D., Kratz, K., Lendlein, A. %D 2017 %J Polymers for Advanced Technologies %N 10 %P 1269-1277 %R doi:10.1002/pat.3973 %T Morphological analysis of differently sized highly porous poly(ether imide) microparticles by mercury porosimetry %U https://doi.org/10.1002/pat.3973 10 %X Highly porous poly(ether imide) (PEI) microparticles prepared by a spraying/coagulation process are discussed as candidate adsorber materials for apheresis applications, i.e. removal of uremic toxins from the blood of renal failure patients. PEI particles obtained by the aforementioned procedure can have a broad size distribution with particle diameters ranging from 20 to 800 µm. In order to further estimate the adsorption behavior of PEI microparticles packed in application relevant apheresis modules, a quantitative information about the relation between particle size and pore morphology is required. In this study, we explored whether the intraparticle porosity of PEI microparticles varies with altering the diameter of the particulate adsorbers. By an analytical wet sieving procedure, the obtained PEI microparticles were separated into five size fractions, which were analyzed by mercury intrusion porosimetry, nitrogen adsorption, and scanning electron microscopy. Mercury intrusion porosimetry revealed for all size fractions high porosity values in the range from 78% to 84% with pore diameters in the range from 10 to 1000 nm. A bimodal pore size distribution was found having a first peak at around 100 nm, while a second pronounced peak maximum was found at higher pore sizes that increased with raising particle diameter from 300 nm for the smallest particle size fraction (50–100 µm) to 700 nm for particles with a diameter of 200 to 250 µm. %0 journal article %@ 1042-7147 %A Blocki, A., Loewenberg, C., Jiang, Y., Kratz, K., Neffe, A.T., Jung, F., Lendlein, A. %D 2017 %J Polymers for Advanced Technologies %N 10 %P 1245-1251 %R doi:10.1002/pat.3947 %T Response of encapsulated cells to a gelatin matrix with varied bulk and microenvironmental elastic properties %U https://doi.org/10.1002/pat.3947 10 %X Gelatin-based hydrogels offer various biochemical cues that support encapsulated cells and are therefore suitable as cell delivery vehicles in regenerative medicine. However, besides the biochemical signals, biomechanical cues are crucial to ensure an optimal support of encapsulated cells. Hence, we aimed to correlate the cellular response of encapsulated cells to macroscopic and microscopic elastic properties of glycidylmethacrylate (GMA)-functionalized gelatin-based hydrogels. To ensure that different observations in cellular behavior could be attributed to differences in elastic properties, an identical concentration as well as degree of functionalization of biopolymers was utilized to form covalently crosslinked hydrogels. Elastic properties were merely altered by varying the average gelatin-chain length. Hydrogels exhibited an increased degree of swelling and a decreased bulk elastic modulus G′ with prolonged autoclaving of the starting solution. This was accompanied by an increase of hydrogel mesh size and thus by a reduction of crosslinking density. Tougher hydrogels retained the largest amount of cells; however, they also interfered with cell viability. Softer gels contained a lower cell density, but supported cell elongation and viability. Observed differences could be partially attributed to differences in bulk properties, as high crosslinking densities interfere with diffusion and cell spreading and thus can impede cell viability. Interestingly, a microscopic elastic modulus in the range of native soft tissue supported cell viability and elongation best while ensuring a good cell entrapment. In conclusion, gelatin-based hydrogels providing a soft tissue-like microenvironment represent adequate cell delivery vehicles for tissue engineering approaches. %0 lecture %@ %A Schroeter, M., Lendlein, A. %D 2017 %J %T Basic Organic Chemistry %U %X %0 conference lecture %@ %A Wang, W., Li, W., Wang, J., Hu, Q., Balk, M., Bieback, K., Stamm, C., Jung, F., Tang, G., Lendlein, A., Ma, N. %D 2017 %J 36th Conference of the German Society for Clinical Microcirculation and Hemorheology %T Folate receptor mediated genetic modification of human mesenchymal stem cells via folic acid-polyethylenimine-grafted poly(N-3-hydroxypropyl)aspartamide %U %X %0 journal article %@ 1042-7147 %A Hommes-Schattmann, P.J., Neffe, A.T., Ahmad, B., Williams, G.R., M´Bele, G., Vanneaux, V., Menasche, P., Kalfa, D., Lendlein, A. %D 2017 %J Polymers for Advanced Technologies %N 10 %P 1312-1317 %R doi:10.1002/pat.3963 %T RGD constructs with physical anchor groups as polymer co-electrospinnable cell adhesives %U https://doi.org/10.1002/pat.3963 10 %X The tissue integration of synthetic polymers can be promoted by displaying RGD peptides at the biointerface with the objective of enhancing colonization of the material by endogenous cells. A firm but flexible attachment of the peptide to the polymer matrix, still allowing interaction with receptors, is therefore of interest. Here, the covalent coupling of flexible physical anchor groups, allowing for temporary immobilization on polymeric surfaces via hydrophobic or dipole–dipole interactions, to a RGD peptide was investigated. For this purpose, a stearate or an oligo(ethylene glycol) (OEG) was attached to GRGDS in 51–69% yield. The obtained RGD linker constructs were characterized by NMR, IR and MALDI-ToF mass spectrometry, revealing that the commercially available OEG and stearate linkers are in fact mixtures of similar compounds. The RGD linker constructs were co-electrospun with poly(p-dioxanone) (PPDO). After electrospinning, nitrogen could be detected on the surface of the PPDO fibers by X-ray photoelectron spectroscopy. The nitrogen content exceeded the calculated value for the homogeneous material mixture suggesting a pronounced presentation of the peptide on the fiber surface. Increasing amounts of RGD linker constructs in the electrospinning solution did not lead to a detection of an increased amount of peptide on the scaffold surface, suggesting inhomogeneous distribution of the peptide on the PPDO fiber surface. Human adipose-derived stem cells cultured on the patches showed similar viability as when cultured on PPDO containing pristine RGD. The fully characterized RGD linker constructs could serve as valuable tools for the further development of tissue-integrating polymeric scaffolds. %0 journal article %@ 1386-0291 %A Zou, J., Wang, W., Neffe, A.T., Xu, X., Li, Z., Deng, Z., Sun, X. Ma, N., Lendlein, A. %D 2017 %J Clinical Hemorheology and Microcirculation %N 3-4 %P 297-307 %R doi:10.3233/CH-179210 %T Adipogenic differentiation of human adipose derived mesenchymal stem cells in 3D architectured gelatin based hydrogels (ArcGel) %U https://doi.org/10.3233/CH-179210 3-4 %X Polymeric matrices mimicking multiple functions of the ECM are expected to enable a material induced regeneration of tissues. Here, we investigated the adipogenic differentiation of human adipose derived mesenchymal stem cells (hADSCs) in a 3D architectured gelatin based hydrogel (ArcGel) prepared from gelatin and L-lysine diisocyanate ethyl ester (LDI) in an one-step process, in which the formation of an open porous morphology and the chemical network formation were integrated. The ArcGel was designed to support adipose tissue regeneration with its 3D porous structure, high cell biocompatibility, and mechanical properties compatible with human subcutaneous adipose tissue. The ArcGel could support initial cell adhesion and survival of hADSCs. Under static culture condition, the cells could migrate into the inner part of the scaffold with a depth of 840±120 μm after 4 days, and distributed in the whole scaffold (2 mm in thickness) within 14 days. The cells proliferated in the scaffold and the fold increase of cell number after 7 days of culture was 2.55±0.08. The apoptotic rate of hADSCs in the scaffold was similar to that of cells maintained on tissue culture plates. When cultured in adipogenic induction medium, the hADSCs in the scaffold differentiated into adipocytes with a high efficiency (93±1%). Conclusively, this gelatin based 3D scaffold presented high cell compatibility for hADSC cultivation and differentiation, which could serve as a potential implant material in clinical applications for adipose tissue reparation and regeneration. %0 conference poster %@ %A Liu, Y., Razzaq, M., Rudolph, T., Kratz, K., Lendlein, A. %D 2017 %J XXVI International Materials Research Congress (IMRC) 2017; Symp. F4: Shape-memory and self-repairing materials %T Polymeric Microcuboids Exhibiting Micro- and Nano-Level Shape Changes %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2017 %J Marie Curie Tag 2017; Marie-Curie-Gymnasium Ludwigsfelde %T Kunststoffe in der Medizin %U %X %0 conference poster %@ %A Heuchel, M., Gerber, D., Weigel, T., Kratz, K., Lendlein, A. %D 2017 %J Polymers for Advanced Technologies Conference 2017 %T Morphological analysis of porous poly(ether imide) microparticles %U %X %0 conference lecture %@ %A Behl, M., Balk, M., Zhang, P., Nöchel, U., Lendlein, A. %D 2017 %J XXVI International Materials Research Congress 2017 %T Shape-memory hydrogels as a technology platform for soft actuators %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2017 %J Besuch eines Chemiekurses der Maxim-Gorki-Gesamtschule Kleinmachnow %T Kunststoffe in der Medizin %U %X %0 conference lecture %@ %A Rudolph, T., Liu, Y., Razzaq, M., Fang, L., Kratz, K., Lendlein, A. %D 2017 %J Polymers for Advanced Technologies Conference 2017 %T Miniaturized polymeric micro-cuboids prepared from crystallizable copolymer networks investigated on the nano- and micro-level %U %X %0 journal article %@ 1386-0291 %A Krueger-Genge, A., Hiebl, B., Franke, R.P., Lendlein, A., Jung, F. %D 2017 %J Clinical Hemorheology and Microcirculation %N 3-4 %P 309-318 %R doi:10.3233/CH-179211 %T Effects of Tacrolimus or Sirolimus on the adhesion of vascular wall cells: Controlled in-vitro comparison study %U https://doi.org/10.3233/CH-179211 3-4 %X These data show that in a non-flow model the cytostatic drug Tacrolimus reduced the number of adherent endothelial cells less than Sirolimus, as long as the drug concentration did not surpass 10–6 mol/l. At the limits of solubility, Sirolimus (1×10–5 mol/l) reduced the number of adherent endothelial cells less than Tacrolimus (6×10–5 mol/l), which induced detachment of endothelial cells. %0 journal article %@ 1386-0291 %A Blocki, A., Loeper, F., Chirico, N., Neffe, A.T., Jung, F., Stamm, C., Lendlein, A. %D 2017 %J Clinical Hemorheology and Microcirculation %N 3-4 %P 251-259 %R doi:10.3233/CH-179206 %T Engineering of cell-laden gelatin-based microcapsules for cell delivery and immobilization in regenerative therapies %U https://doi.org/10.3233/CH-179206 3-4 %X 10 wt% GMA-gelatin-based hydrogels with E moduli properties comparable to the native cellular niche proved to be a promising biomaterial suitable for the production of cell-laden microcapsules and shall be evaluated further for biomedical application. %0 journal article %@ 1742-5689 %A Schoene, A.-C., Roch, T., Schulz, B., Lendlein, A. %D 2017 %J Journal of the Royal Society Interface %N 130 %P 20161028 %R doi:10.1098/rsif.2016.1028 %T Evaluating polymeric biomaterial–environment interfaces by Langmuir monolayer techniques %U https://doi.org/10.1098/rsif.2016.1028 130 %X Polymeric biomaterials are of specific relevance in medical and pharmaceutical applications due to their wide range of tailorable properties and functionalities. The knowledge about interactions of biomaterials with their biological environment is of crucial importance for developing highly sophisticated medical devices. To achieve optimal in vivo performance, a description at the molecular level is required to gain better understanding about the surface of synthetic materials for tailoring their properties. This is still challenging and requires the comprehensive characterization of morphological structures, polymer chain arrangements and degradation behaviour. The review discusses selected aspects for evaluating polymeric biomaterial–environment interfaces by Langmuir monolayer methods as powerful techniques for studying interfacial properties, such as morphological and degradation processes. The combination of spectroscopic, microscopic and scattering methods with the Langmuir techniques adapted to polymers can substantially improve the understanding of their in vivo behaviour. %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2017 %J Vortrag am Vicco-von-Buelow Gymnasium Stahnsdorf - Berufsorientierungstag %T Materialforschung - Viele Diziplinen zu einem Ziel. Verwendung von Polymeren in der Medizin %U %X %0 conference lecture %@ %A Balk, M., Behl, M., Nöchel, U., Lendlein, A. %D 2017 %J Polymers for Advanced Technologies Conference 2017 %T Complex movements enabled by triple-shape hydrogels %U %X valves for flow rate control in an aqueous media. %0 journal article %@ 2059-8521 %A Peng, X., Behl, M., Zhang, P., Mazurek-Budzynska, M., Feng, Y., Lendlein, A. %D 2017 %J MRS Advances %N 47 %P 2551-2559 %R doi:10.1557/adv.2017.486 %T Synthesis and Characterization of Multiblock Poly(Ester-Amide-Urethane)s %U https://doi.org/10.1557/adv.2017.486 47 %X In this study, a multiblock copolymer containing oligo(3-methyl-morpholine-2,5-dione) (oMMD) and oligo(3-sec-butyl-morpholine-2,5-dione) (oBMD) building blocks obtained by ring-opening polymerization (ROP) of the corresponding monomers, was synthesized in a polyaddition reaction using an aliphatic diisocyanate. The multiblock copolymer (pBMD-MMD) provided a molecular weight of 40,000 g·mol−1, determined by gel permeation chromatography (GPC). Incorporation of both oligodepsipeptide segments in multiblock copolymers was confirmed by 1H NMR and Matrix Assisted Laser Desorption/Ionization Time Of Flight Mass Spectroscopy (MALDI-TOF MS) analysis. pBMD-MMD showed two separated glass transition temperatures (61 °C and 74 °C) indicating a microphase separation. Furthermore, a broad glass transition was observed by DMTA, which can be attributed to strong physical interaction i.e. by H-bonds formed between amide, ester, and urethane groups of the investigated copolymers. The obtained multiblock copolymer is supposed to own the capability to exhibit strong physical interactions. %0 journal article %@ 2059-8521 %A You, Z., Behl, M., Loewenberg, C., Lendlein, A. %D 2017 %J MRS Advances %N 47 %P 2571-2579 %R doi:10.1557/adv.2017.491 %T pH-sensitivity and Conformation Change of the N-terminal Methacrylated Peptide VK20 %U https://doi.org/10.1557/adv.2017.491 47 %X N-terminal methacrylation of peptide MAX1, which is capable of conformational changes by variation of the pH, results in a peptide, named VK20. Increasing the reactivity of this terminal group enables further coupling reactions or chemical modifications of the peptide. However, this end group functionalization may influence the ability of conformational changes of VK20, as well as its properties. In this paper, the influence of pH on the transition between random coil and ß-sheet conformation of VK20, including the transition kinetics, were investigated. At pH values of 9 and higher, the kinetics of ß-sheet formation increased for VK20, compared to MAX1. The self-assembly into ß-sheets recognized by the formation of a physically crosslinked gel was furthermore indicated by a significant increase of G’. An increase in pH (from 9 to 9.5) led to a faster gelation of the peptide VK20. Simultaneously, G’ was increased from 460 ± 70 Pa (at pH 9) to 1520 ± 180 Pa (at pH 9.5). At the nanoscale, the gel showed a highly interconnected fibrillary network structure with uniform fibril widths of approximately 3.4 ± 0.5 nm (N=30). The recovery of the peptide conformation back to random coil resulted in the dissolution of the gel, whereby the kinetics of the recovery depended on the pH. Conclusively, the ability of MAX1 to undergo conformational changes was not affected by N-terminal methacrylation whereas the kinetics of pH-sensitive ß-sheet formations has been increased. %0 book part %@ %A Heek, T., Behl, M., Lendlein, A. %D 2017 %J Handbook of Telechelic Polyesters, Polycarbonates, and Polyethers %P 115-183 %R doi:10.1201/9781315364469-5 %T Telechelic Poly(Epsilon-Caprolactone)s: Synthesis and Applications %U https://doi.org/10.1201/9781315364469-5 %X A key challenge of polymer chemistry is the synthesis and development of polymeric materials whose chemical and physical characteristics fit their intended field of application. In general, three distinct features of a polymer determine these properties: the chemical composition (i.e., the used (co‑)monomers)), the topology (e.g., linear, branched, network), and the nature and distribution of chemical functional groups, as these determine potential chemical reactivity or physical interactions with the environment. The combination of these design motifs is referred to as the polymer architecture [1]. A modification in one of these parameters can cause significant changes in the resulting properties of a certain polymer. %0 conference lecture %@ %A You, Z., Behl, M., Lendlein, A. %D 2017 %J MRS Spring Meeting 2017 %T Shape-memory cryogels based on conformational transition of peptides %U %X %0 journal article %@ 0142-9612 %A Lohmann, P., Willuweit, A., Neffe, A.T., Geisler, S., Gebauer, T.P., Beer, S., Coenen, H.H., Fischer, H., Hermanns-Sachweh, B., Lendlein, A., Shah, N.J., Kiessling, F., Langen, K.-J. %D 2017 %J Biomaterials %P 158-169 %R doi:10.1016/j.biomaterials.2016.10.039 %T Bone regeneration induced by a 3D architectured hydrogel in a rat critical-size calvarial defect %U https://doi.org/10.1016/j.biomaterials.2016.10.039 %X Bone regeneration can be stimulated by implantation of biomaterials, which is especially important for larger bone defects. Here, healing potency of the porous ArcGel was evaluated in a critical-size calvarial bone defect in rats in comparison with clinical standard autologous bone and Bio-Oss® Collagen (BioOss), a bone graft material frequently used in clinics. Bone healing and metabolic processes involved were monitored longitudinally by [18F]-fluoride and [18F]-FDG μ-PET/CT 1d, 3d, 3w, 6w, and 12w post implantation. Differences in quality of bone healing were assessed by ex vivo μ-CT, mechanical tests and histomorphometry. The amount of bone formed after implantation of ArcGel was comparable to autologous bone and superior to BioOss (histomorphometry). Furthermore, microarchitecture of newly formed bone was more physiological and better functional in case of ArcGel (push-out tests). [18F]-FDG uptake increased until 3d after implantation, and decreased until 12w for both ArcGel and BioOss. [18F]-fluoride uptake increased until 3w post implantation for all materials, but persisted significantly longer at higher levels for BioOss, which indicates a prolonged remodelling phase. The study demonstrates the potential of ArcGel to induce restitutio ad integrum comparable with clinical standard autologous bone and better bone regeneration in large defects compared to a commercial state-of-the-art biomaterial. %0 journal article %@ 2046-2069 %A Mazurek-Budzynska, M., Razzaq, M.Y., Rokicki, G., Behl, M., Lendlein, A. %D 2017 %J MRS Advances %N 47 %P 2529-2536 %R doi:10.1557/adv.2017.471 %T High-Strain Shape-Memory Properties of Poly(Carbonate-Urea-Urethane)s Based on Aliphatic Oligocarbonates and L-Lysine Diisocyanate %U https://doi.org/10.1557/adv.2017.471 47 %X The simultaneous capability of high-strain deformation and high shape recovery ratio constitutes a great challenge in design of the shape-memory polymers. Here we report on poly(carbonate-urea-urethane)s (PCUUs) synthesized by a precursor route, based on oligo(alkylene carbonate) diols, L-lysine diisocyanate (LDI), and water vapor. When programed with a strain of ε prog = 800%, the PCUU networks exhibited a one-way shape-memory effect (1W-SME) with excellent shape fixity (> 97%) and shape recovery (> 99%) ratios. The switching temperatures (T sw) varied between 50 and 56 °C and correlated to the melting transitions of the switching domains. The obtained PCUUs capable of high-strain are interesting candidate materials for degradable biomaterials as required in smart medical devices. %0 journal article %@ 1381-6128 %A Wang, W., Deng, Z., Xu, X., Li, Z., Jung, F., Ma, N., Lendlein, A. %D 2017 %J Current Pharmaceutical Design %N 26 %P 3814-3832 %R doi:10.2174/1381612823666170622110654 %T Functional Nanoparticles and their Interactions with Mesenchymal Stem Cells %U https://doi.org/10.2174/1381612823666170622110654 26 %X Mesenchymal stem cells (MSCs) have become one of the most important cell sources for regenerative medicine. However, some mechanisms of MSC-based therapy are still not fully understood. The clinical outcome may be restricted by some MSC-related obstacles such as the low survival rate, differentiation into undesired lineages and malignant transformation. In recent years, with the emergence of nanotechnology, various types of multifunctional nanoparticles (NPs) have been designed, prepared and explored for bio-related applications. There is high potential of NPs in biomedical applications, attributed to the high capacity of cellular internalization in MSCs and their multiple functionalities. They can be used either as labeling agent to track MSCs for mechanism study or as gene/drug delivery carriers to regulate the cellular behavior and functions of MSCs. However, the application of NPs may be accompanied by some undesirable effects, as some NPs can induce cell death, inhibit cell proliferation or influence the differentiation of MSCs. Aiming to provide a comprehensive understanding of the interaction between NPs and MSCs, recent progress in the design and preparation of multifunctional NPs is summarized in this review, mechanisms of cellular internalization of the NPs are discussed, the main applications of multifunctional NPs in MSCs are highlighted and overview about cellular response of MSCs to different NPs is given. Future studies aiming on design and development of NPs with multifunctionality may open a new field of applying nanotechnology in stem cell-based therapy. %0 conference lecture %@ %A Behl, M., Balk, M., Lendlein, A. %D 2017 %J Polymers for Advanced Technologies Conference 2017 %T Robot Assisted Synthesis of Alternating Multiblock Copolymers Based on Oligo(ε-caprolactone)/Oligotetrahydrofuran %U %X %0 journal article %@ 1042-7147 %A Dal Bianco, A., Wischke, C., Zhou, S., Lendlein, A. %D 2017 %J Polymers for Advanced Technologies %N 10 %P 1263-1268 %R doi:10.1002/pat.3917 %T Controlling surface properties and permeability of polyglycerol network films %U https://doi.org/10.1002/pat.3917 10 %X While branched polyglycerol (PG)-based molecules are well established as hydrophilic particles, the capacity of utilizing PG in bulk materials and opportunities arising by their further surface functionalization have only recently been considered. Here we investigated how the mold used in PG network synthesis may affect surface composition and how the permeability of substances through PG can be controlled by altering network structure, i.e. introducing 20 mol% oligoethylene glycol (OEG) bifunctional spacer molecules. Overall, PG-based bulk network materials were shown to be tailorable, hydrophilic, low swelling and relatively stiff polyether-based materials, with low impact of salt onto material properties. Based on these features, but also on the principal capacity of free hydroxyl groups to be used for functionalization reactions, these materials may be an interesting platform for medical and technical applications, e.g. as diffusion-rate controlling membrane in aqueous environment. %0 journal article %@ 1042-7147 %A Balk, M., Behl, M., Yang, J., Li, Q., Wischke, C., Feng, Y., Lendlein, A. %D 2017 %J Polymers for Advanced Technologies %N 10 %P 1278-1284 %R doi:10.1002/pat.3911 %T Design of polycationic micelles by self‐assembly of polyethyleneimine functionalized oligo[(ε‐caprolactone)‐co‐glycolide] ABA block copolymers %U https://doi.org/10.1002/pat.3911 10 %X Cationic polymeric micelles are of interest as delivery materials for nucleotides allowing condensation and transport of anionic macromolecules and enabling the reduction of cytotoxicity of polyethyleneimine, the current standard of vectors for non-viral nucleic acid delivery. In addition, micelles based on a degradable core would be capable to degrade hydrolytically and release their payload, which should preferably occur after uptake in early endosomes providing a pH of 5.5. We explored whether degradable and amphiphilic ABA block copolymers from hyperbranched polyethyleneimine A blocks and B blocks based on hydrophobic oligoesters (CG) can be created, which can degrade in a pH range relevant for the early endosomes. CG was synthesized by ring-opening polymerization of ε-caprolactone and diglycolide. Polycationic micelles with particle sizes between 19 ± 1 and 43 ± 2 nm were obtained by self-assembly of the ABA block copolymers with different chain lengths of B blocks and/or co-assembly with a diblock copolymer from poly(ethylene glycol) (PEG) functionalized CG oligoester in phosphate-buffered saline solution. Mixed micelles containing PEG-CG showed a decreased zeta potential, suggesting a shielding by dangling PEG chains at the micelle surfaces. Sizes of cationic micelles were stable at pH = 7.4 over the studied time period of 2 weeks at 37 °C. The hydrolytic degradation was controlled by the composition of the CG core and was accelerated when the pH was decreased to 5.5 as detected by increasing micelle sizes. In this way, the polycationic micelles may act as an on-demand delivery system of condensed macromolecules. %0 conference lecture %@ %A Brunacci, N., Wischke, C., Neffe, A., Lendlein, A. %D 2017 %J BIFTM PhD Symposium - BioInterfaces in Technology and Medicine %T Evaluation of surfactants for the formation of sub-micron depsipeptide particles %U %X %0 journal article %@ 1042-7147 %A Mazurek-Budzynska, M., Razzaq, M.Y., Tomczyk, K., Rokicki, G., Behl, M., Lendlein, A. %D 2017 %J Polymers for Advanced Technologies %N 10 %P 1285-1293 %R doi:10.1002/pat.3948 %T Poly(carbonate‐urea‐urethane) networks exhibiting high‐strain shape‐memory effect %U https://doi.org/10.1002/pat.3948 10 %X A challenge in the design of shape-memory polymers (SMPs) is to achieve high deformability with a simultaneous high shape recovery ratio. Here we explored, whether SMPs featuring large deformation capability and high shape recovery ratios can be created as polymer networks providing two kinds of netpoints based on covalent bonds and physical interactions. As a model system, we selected poly(carbonate-urea-urethane)s (PCUUs) synthesized by a precursor route, based on oligo(alkylene carbonate) diols, isophorone diisocyanate (IPDI), and water vapor. The PCUU networks exhibited a one-way shape-memory effect (1W-SME) with programmed strains up to εprog = 1000% whereby they provided excellent shape fixity (92–97%) and shape recovery (≥99%) ratios. The switching temperatures (Tsw) varied between 36 and 65 °C and increased with the increasing molecular weight of the oligo(alkylene carbonate) diol and length of the hydrocarbon chain between the carbonate linkages. Tsw was also influenced by the strain applied during programming (εprog). Poly(carbonate-urethane)s have been reported to have good biocompatibility and biostability, which in the combination of high-strain capacity and high Young's modulus makes the obtained PCUUs interesting candidate materials suitable for medical devices such as medical sutures or vascular stents. %0 journal article %@ 1932-6254 %A Haase, T., Krost, A., Sauter, T., Kratz, K., Peter, J., Kamann, S., Jung, F., Lendlein, A., Zohlnhöfer, D., Rüder, C. %D 2017 %J Journal of Tissue Engineering and Regenerative Medicine %N 4 %P 1034-1044 %R doi:10.1002/term.2002 %T In vivo biocompatibility assessment of poly (ether imide) electrospun scaffolds %U https://doi.org/10.1002/term.2002 4 %X Poly(ether imide) (PEI), which can be chemically functionalized with biologically active ligands, has emerged as a potential biomaterial for medical implants. Electrospun PEI scaffolds have shown advantageous properties, such as enhanced endothelial cell adherence, proliferation and low platelet adhesion in in vitro experiments. In this study, the in vivo behaviour of electrospun PEI scaffolds and PEI films was examined in a murine subcutaneous implantation model. Electrospun PEI scaffolds and films were surgically implanted subcutaneously in the dorsae of mice. The surrounding subcutaneous tissue response was examined via histopathological examination at 7 and 28 days after implantation. No serious adverse events were observed for both types of PEI implants. The presence of macrophages or foreign body giant cells in the vicinity of the implants and the formation of a fibrous capsule indicated a normal foreign body reaction towards PEI films and scaffolds. Capsule thickness and inflammatory infiltration cells significantly decreased for PEI scaffolds during days 7–28 while remaining unchanged for PEI films. The infiltration of cells into the implant was observed for PEI scaffolds 7 days after implantation and remained stable until 28 days of implantation. Additionally some, but not all, PEI scaffold implants induced the formation of functional blood vessels in the vicinity of the implants. Conclusively, this study demonstrates the in vivo biocompatibility of PEI implants, with favourable properties of electrospun PEI scaffolds regarding tissue integration and wound healing. %0 conference poster %@ %A Quinn, S., Kratz, K., Tirelli, N., Lendlein, A., Blaker, J. %D 2017 %J Polymers for Advanced Technologies Conference %T Solution blow spinning of poly(vinylidene fluoride) at different temperatures %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2017 %J 10th International Conference on Cachexia, Sarcopenia and Muscle Wasting %T Device-based tissue regeneration by multifunctional polymers %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2017 %J MRS Spring Meeting 2017 %T Shape-memory effects - soft materials and polymers in small scale %U %X %0 conference lecture %@ %A Neffe, A., Naolou, T., Lendlein, A. %D 2017 %J MRS Spring Meeting 2017 %T Influence of metal softness on the ring-opening polymerization of 2;5-morpholinediones and lactones %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2017 %J Lecture at the Biomedical Polymers Laboratory; Soochow University %T Shape-memory effects of polymers %U %X %0 conference lecture %@ %A Lendlein, A., Schroeter, M. %D 2017 %J Tag der Wissenschaften am Weinberg-Gymnasium 2017 %T Chemie ist nicht nur wenn es knallt und stinkt! - Intelligente Kunststoffe %U %X %0 conference poster %@ %A Krüger-Genge, A., Hiebl, B., Schunck, W., Müller, D., Blaschke, F., Franke, R., Lendlein, A., Jung, F. %D 2017 %J 36. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheologie (DGKMH) %T Effects of tacrolimus or sirolimus on the adhesion of vascular wall cells: controlled in-vitro camparison study %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2017 %J Seminar of the International Centre of Biocybernetics (ICB) on „Nanoparticles and Nanotechnology for Biomedical Engineering; Biotechnology and Medicine” %T Nanoengineering multifunctional biomaterials %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2017 %J Lecture at the Institute of Textiles and Clothing; The Hong Kong Polytechnic University %T Recent trends in shape-memory polymers %U %X %0 conference lecture %@ %A Neffe, A., Piluso, S., Lendlein, A. %D 2017 %J Polymers for Advanced Technologies Conference 2017 %T Clicked gelatin hydrogels - Multifunctional networks showing enzymatic surface degradation %U %X %0 conference poster %@ %A Hommes-Schattmann, P., Neffe, A., Zierke, M., Lendlein, A. %D 2017 %J XXVI International Materials Research Congress (IMRC) 2017; Symp. F4: Shape-memory and self-repairing materials %T Polyester urethanes with multiblock sequence structure and alkynyl-functionalized side chains %U %X conditions. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2017 %J XXVI International Materials Research Congress (IMRC) 2017; Symp. C5: New trends in polymer chemistry and characterization %T Shape-memory polymers %U %X %0 conference lecture %@ %A You, Z., Behl, M., Lendlein, A. %D 2017 %J BIFTM PhD Symposium - BioInterfaces in Technology and Medicine %T Conformational transition of peptide functionalized cryogels enabling shape-memory capability %U %X %0 conference lecture %@ %A Ma, N., Xu, X., Wang, W., Li, Z., Zou, J., Kratz, K., Lendlein, A. %D 2017 %J MRS Spring Meeting 2017 %T Regulation of mesenchymal stem cell behavior and secretion via microscale surface roughness %U %X %0 conference lecture %@ %A Bhuvanesh, T., Roch, T., Schulz, B., Ma, N., Lendlein, A. %D 2017 %J BIFTM PhD Symposium - BioInterfaces in Technology and Medicine %T Understanding protein-polymer biointerfaces to modulate cell responses %U %X %0 conference lecture %@ %A Zou, J., Wang, W., Neffe, A., Xu, X., Li, Z., Deng, Z., Sun, X., Ma, N., Lendlein, A. %D 2017 %J 36. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheologie (DGKMH) %T Adipogenic differentiation of human adipose derived mesenychmal stem cells in 3D architectured gelatin-based hydrogels (ArcGel) %U %X %0 conference lecture %@ %A Roch, T., Kratz, K., Ma, N., Lendlein, A. %D 2017 %J 36. Jahrestagung der Deutschen Gesellschaft für Klinische Mikrozirkulation und Hämorheologie (DGKMH) %T Standard elution protocols are insufficient to determine the endotoxin burden of biomaterials %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2017 %J Berufsorientierung für Schülerinnen und Schüler der 5. Klassen %T Forschung bei HZG - Polymere in der Medizin %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2017 %J Lecture at the Center for Education and Research on Macromolecules (CERM); University of Liège %T Shape-Memory Effects in Polymers - Programmed Shape Shifts on Demand %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2017 %J Girls & Boys Day 2017 - Zukunftstag für Mädchen und Jungen %T Forschung bei HZG - Polymere in der Medizin %U %X %0 conference lecture %@ %A Keller, M., Lendlein, A. %D 2017 %J Girls & Boys Day 2017 - Zukunftstag für Mädchen und Jungen %T HZG in Teltow und Kunststoffe in der Medizin %U %X %0 conference poster %@ %A Xu, X., Wang, W., Kratz, K., Ma, N., Lendlein, A. %D 2017 %J MRS Spring Meeting 2017 %T Microstructured stubstrates modulate interleukin-6 secretion in human mesenchymal stem cells %U %X %0 conference poster %@ %A Peng, X., Behl, M., Zhang, P., Lendlein, A. %D 2017 %J MRS Spring Meeting 2017 %T Decrease of Tg of polymers from morpholinediones by modification with hexyl groups %U %X %0 conference poster %@ %A Zhang, P., Behl, M., Peng, X., Razzaq, M., Lendlein, A. %D 2017 %J MRS Spring Meeting 2017 %T Ultrasonic Cavitation Induced Shape-Memory Effect in Porous Polymer Networks %U %X %0 conference lecture %@ %A Wischke, C., Racheva, M., Störmann, F., Bähr, E., Lendlein, A. %D 2017 %J MRS Spring Meeting 2017 %T Functional hydrogels and particles from crosslinked polymeric telechelics %U %X %0 journal article %@ 0032-3861 %A Peng, X., Behl, M., Zhang, P., Mazurek-Budzynska, M., Razzaq, M.Y., Lendlein, A. %D 2016 %J Polymer %P 318-326 %R doi:10.1016/j.polymer.2016.10.033 %T Hexyl-modified morpholine-2,5-dione-based oligodepsipeptides with relatively low glass transition temperature %U https://doi.org/10.1016/j.polymer.2016.10.033 %X Oligodepsipeptides (oDPs), alternating copolymers of an α-amino acid and an α-hydroxy acid, are typically created by ring-opening polymerization (ROP) of morpholine-2,5-dione derivatives (MDs). In general, oDPs exhibit relatively high glass transition temperatures (Tgs) caused by the strong intermolecular H-bonding between amide and ester bonds. So far, it was not reported that variation at α-amino acid moieties in MDs monomers lead to lower Tg. Here we explored whether the thermal properties of the oDPs can be adjusted by introducing a hexyl side chain in the α-hydroxy acid part of the MDs. By synthesizing a MD with an atactic pendant hexyl group at position 3, the influence of a modification at position 6 compared to a modification at position 3 towards ROP was investigated. In both cases the atactic bulky side groups hindered the H-bonding between chain segments resulting in a significant reduction of the Tgs to a temperature around human body temperature (32 and 36 °C) in contrast to ROP of a MD providing a methyl group at position 3 and a Tg ≈ 65 °C. Such oDPs could be interesting candidate materials for biomedical applications such as degradable implants. %0 conference lecture (invited) %@ %A Schulz, B., Lendlein, A. %D 2016 %J Deutsch-Russischer Karrieretag 2016 %T Die Helmholtz-Graduiertenschule "Macromolecular Bioscience" - Ein Kooperationsprojekt ausseruniversitaerer und universitaerer Forschung und Lehre %U %X %0 conference poster %@ %A Naolou, T., Neffe, A.T., Lendlein, A. %D 2016 %J International Conference on Dermal Drug Delivers by Nanocarrierrs, SFB Konferenz %T Ring-Opening polymerization of morpholine-2,5-diones by iron(II) acetate and metal alkoxides %U %X %0 conference poster %@ %A Peng, X., Behl, M., Zhang, P., Lendlein, A. %D 2016 %J International Conference on Dermal Drug Delivers by Nanocarrierrs, SFB Konferenz %T Morpholine-2,5-diones with hexyl side chains as monomers for oligodepsipeptides with decreased glass transition temperature %U %X %0 conference poster %@ %A Li, Z., Wang, W., Kratz, K., Küchler, J., Xu, X., Zou, J., Deng, Z., Sun, X., Gossen, M., Ma, N., Lendlein, A. %D 2016 %J 35. Jahrestagung der Deutschen Gesellschaft für klinische Mikrozirkulation und Hämorheologie (DGKMH) %T Neural differentiation of human induced pluripotent stem cells on the structured surface %U %X lnduced pluripotent stem cells (iPSCs) own the capacity to develop into all cell types of the adult body, presenting high potential in regenerative medicine. Regulating and controlling the differentiation of iPSCs via the surface topographic cues of biomaterials is a promising and safe approach to enhance their therapeutic efficacy. In this study, we tested the effects of microscale roughness on differentiation of human iPSCs into neural progenitor cells and dopaminergic neuron cells using polystyrene surface with different roughness levels. Neural differentiation of human iPSCs could be strongly influenced by microscale roughness. Upregulated neuronal markers were detected in iPSCs cells seeded on rougher surface, as examined by real-time PCR and immunost aini ng. Particularly, the intermedium rough surface significantly improved the neuronal marker expression as compared other surfaces. This study demonstrates that a surface with an appropriated microscale roughness level can promote the differentiation of human iPSCs towards the neuronal lineage. Our study suggests the potential applications of controllable iPSCs cell differentiation via surface structure, and highlights the strategy of design and development of structured surface on regulating stem cell development. %0 conference lecture %@ %A Braune, S., Baeckemo-Johansson, J., Kratz, K., Jung, F., Lendlein, A. %D 2016 %J 18th Conference of the European Society for Clinical Hemorheology and Microcirculation, ESCHM 2016 %T The Influence of different rewetting procedures on the thrombogenicity of nanoporous poly(ether imide) microparticles %U %X %0 conference lecture %@ %A Lendlein, A., Neffe, A.T., Ma, N., Behl, M., Wischke, C. %D 2016 %J International Conference on Dermal Drug Delivers by Nanocarrierrs, SFB Konferenz %T Functional Polymers and Carriers Systems %U %X %0 conference lecture %@ %A Blocki, A., Wang, Y., Koch, M., Jung, F., Bhakoo, K., Raghunath, M., Lendlein, A. %D 2016 %J 18th Conference of the European Society for Clinical Hemorheology and Microcirculation, ESCHM 2016 %T Blood-derived angiogenic cells (BDACs) resemble a hematopoietic pericyte population and are a promosing candidate for therapeutic angiogenesis %U %X %0 conference lecture (invited) %@ %A Wischke, C., Lendlein, A. %D 2016 %J 30. Treffpunkt Medizintechnik 2016 %T Polymerbasierte Materialien fuer Technologie und Medizin %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2016 %J 5th International Conference Smart and Multifunctional Materials, Structures and Systems, CIMTEC 2016 %T Bio-based Polymer Systems with Multifunctionality %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2016 %J Berufsorientierung Vico-von-Buelow Gymnasium %T Biomaterialforschung bei HZG %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2016 %J Girls & Boys Day 2016 %T Forschung bei HZG - Polymere in der Medizin %U %X %0 conference lecture %@ %A Schoene, A.-C., Schulz, B., Lendlein, A. %D 2016 %J 16th International Conference on Organized Molecular Films %T Influence of hydrophobic segments on the enzymatic degradation of multiblock copolymer based Langmuir films %U %X %0 conference lecture %@ %A Schulz, B., Schoene, A.-C., Lendlein, A. %D 2016 %J 16th International Conference on Organized Molecular Films %T Morphologies and Degradation Behaviour of Biodegradable Polymers at the Ai-Water Interface %U %X %0 conference poster %@ %A Mazurek-Budzynska, M., Tomczyk, K., Rokicki, G., Razzaq, M.Y., Behl, M., Lendlein, A. %D 2016 %J Advanced Functional Polymers for Medicine, AFPM 2016 %T Poly(carbonate-urea-urethane) networks exhibiting high-strain shape memory effect %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2016 %J Symposium of the International Faculty for Artificial Organs, INFA 2016 %T Aspects of multi-functionality and clinical translation in biomaterial application %U %X %0 conference lecture (invited) %@ %A Wischke, C., Lendlein, A. %D 2016 %J 9. Innovationsforum Senftenberg %T Benefits and Perspective of interdisziplinary research %U %X %0 conference lecture (invited) %@ %A Schulz, B., Schoene, A.-C., Lendlein, A. %D 2016 %J 5th International Conference Smart and Multifunctional Materials, Structures and Systems, CIMTEC 2016 %T Interplay of morphology and degredation in two-dimensional Polymer films at the air-water interface %U %X %0 conference lecture (invited) %@ %A Kratz, K., Lendlein, A. %D 2016 %J Cross - Innovation - Workshop: Polymere, Neue Perspektiven fuer IVD, Bioanalytik und Medizin %T Multifunktionale Materialien fuer Technologie und Medizin %U %X %0 conference poster %@ %A Kratz, K., Jiang, Y., Liu, Y., Lendlein, A. %D 2016 %J International Conference on Molecular Interaction Engineering, MIE 2016 %T Active Polymer Substrates for 3D Printable Biology %U %X %0 conference lecture %@ %A Jung, F., Krueger-Genge, A., Braune, S., Ma, N., Lendlein, A. %D 2016 %J 18th Conference of the European Society for Clinical Hemorheology and Microcirculation, ESCHM 2016 %T Biological Evaluation of polymer-based Biomaterials %U %X %0 conference poster %@ %A Brunacci, N., Naolou, T., Wischke, C., Neumann, F., Ma, N., Neffe, A.T., Lendlein, A. %D 2016 %J Advanced Functional Polymers for Medicine, AFPM 2016 %T Comparison of particulate carriers for dexamethasone with oligodepsipeptide or OLGA as matrix material %U %X %0 lecture %@ %A Lendlein, A. %D 2016 %J %T BSRT Einfuehrungskurs %U %X %0 conference lecture %@ %A Roch, T., Kratz, K., Ma, N., Lendlein, A. %D 2016 %J 18th Conference of the European Society for Clinical Hemorheology and Microcirculation, ESCHM 2016 %T Dendritic cell responses towards clinically used polydimethylsiloxane and polytetrafluoroethylene %U %X %0 conference poster %@ %A Hommes-Schattmann, P.J., Neffe, A.T., Ahmad, B., Williams, G.R., Vanneaux, V., Menasche, P., Kalfa, D., Lendlein, A. %D 2016 %J Advanced Functional Polymers for Medicine, AFPM 2016 %T Electrospun PPDO- Patches With Incorporated RGD Constructs %U %X %0 conference lecture %@ %A Schulz, C., Krueger-Genge, A., Vukicevic, R., Neffe, A.T., Lendlein, A., Jung, F. %D 2016 %J 18th Conference of the European Society for Clinical Hemorheology and Microcirculation, ESCHM 2016 %T Monolayer formation and shear-resistance of human vein endothelial cells on gelatin-based hydrogels with tailorable elasticity and degradability %U %X %0 conference poster %@ %A Baeckemo-Johansson, J., Reinthaler, M., Braune, S., Lendlein, A., Jung, F. %D 2016 %J 18th Conference of the European Society for Clinical Hemorheology and Microcirculation, ESCHM 2016 %T Shear-induces platelet adherence and activation in a dynamic multiwell-plate system %U %X %0 conference poster %@ %A Dal Bianco, A., Zhou, S., Wischke, C., Lendlein, A. %D 2016 %J Advanced Functional Polymers for Medicine, AFPM 2016 %T Surface properties and permeability of polyglycerol films %U %X %0 editorial %@ 1743-4440 %A Reinthaler, M., Jung, F., Landmesser, U., Lendlein, A. %D 2016 %J Expert Review of Medical Devices %N 11 %P 1001-1003 %R doi:10.1080/17434440.2016.1230013 %T Editorial: Trend to move from permanent metals to degradable, multifunctional polymer or metallic implants in the example of coronary stents %U https://doi.org/10.1080/17434440.2016.1230013 11 %X No abstract %0 conference poster %@ %A Farhan, M., Kratz, K., Lendlein, A. %D 2016 %J Advanced Functional Polymers for Medicine, AFPM 2016 %T Two-way shape-memory networks with large reversible changes %U %X %0 conference poster %@ %A Racheva, M., Wischke, C., Lendlein, A. %D 2016 %J International Conference on Molecular Interaction Engineering, MIE 2016 %T Tyrosinase as biocatalyst for hydrogel synthesis: side reactions affecting bioactive molecules %U %X %0 conference lecture %@ %A Keller, M., Lendlein, A. %D 2016 %J Girls & Boys Day 2016 %T HZG in Teltow und Kunststoffe in der Medizin %U %X %0 conference poster %@ %A Rottke, F., Schulz, B., Eidner, S., Kumke, M.U., Domb, A., Lendlein, A. %D 2016 %J Advanced Functional Polymers for Medicine, AFPM 2016 %T Crystallization of poly(sebacic acid) at the air-water interface %U %X %0 conference poster %@ %A Bhuvanesh, T., Saretia, S., Roch, T., Schoene, A.-C., Rottke, F., Ma, N., Schulz, B., Lendlein, A. %D 2016 %J Advanced Functional Polymers for Medicine, AFPM 2016 %T Langmuir-Schaefer films of fibronectin as designed bionterfaces for culturing stem cells %U %X %0 conference poster %@ %A Balk, M., Behl, M., Yang, J., Li, Q., Wischke, C., Feng, Y., Lendlein, A. %D 2016 %J Advanced Functional Polymers for Medicine, AFPM 2016 %T Design of Polycationic Micelles by Self-Assembly of Polyethyleneimine Functionalized Oligo[(ε-caprolactone)-co-glycolide] ABA Block Copolymers %U %X %0 conference poster %@ %A Neffe, A.T., Piluso, S., Vukicevic, R., Noechel, U., Braune, S., Lendlein, A. %D 2016 %J Advanced Functional Polymers for Medicine, AFPM 2016 %T Sequential Alkyne-Azide Cycloadditions for Functionalized Gelatin Hydrogel Formation %U %X %0 conference poster %@ %A Wischke, C., Tuncaboylu, D.C., Lendlein, A. %D 2016 %J International Conference on Dermal Drug Delivers by Nanocarrierrs, SFB Konferenz %T Microgels from photocrosslinking of cinnamylidene acetic acid modified polyethylene glycol %U %X %0 journal article %@ 0168-3659 %A Wang, W., Balk, M., Deng, Z., Wischke, C., Gossen, M., Behl, M., Ma, N., Lendlein, A. %D 2016 %J Journal of Controlled Release %P 71-79 %R doi:10.1016/j.jconrel.2016.08.004 %T Engineering biodegradable micelles of polyethylenimine-based amphiphilic block copolymers for efficient DNA and siRNA delivery %U https://doi.org/10.1016/j.jconrel.2016.08.004 %X Polycationic micelles have shown advantageous properties as nucleic acid delivery vectors both in vitro and in vivo. In contrast to polycationic micelles reported so far, we designed particles integrating a sufficient nucleic acid condensation capability by polycationic polyethylenimine (PEI) segments as well as only a mild cytotoxic behavior. The micelles composed of a hydrophobic oligoester core with glycolide units resulting in fast degradation after cellular internalization in combination with PEG moieties acting as shielding agents. By grafting branched 25 kDa polyethylenimine (PEI25) and poly(ethylene glycol) (PEG) on poly[(ε-caprolactone)-co-glycolide] (CG), amphiphilic PEI-CG-PEI and PEG-CG block copolymers were used to form a series of micelles via self-assembly of PEI-CG-PEI or co-assembly of both copolymers for DNA and siRNA delivery. This modular system enabled a systematic investigation of different parameters and their synergetic effects as different functions were introduced. The polyplex formation and serum stability, cytotoxicity, and transfection activity could be tailored by changing the CG chain length in PEI-based copolymer, incorporating PEG-CG, and varying the N/P ratio. All micelle-based polyplex compositions showed high DNA transfection activity according to reporter gene-expression and an exceptionally high knockdown in siRNA delivery experiments. Remarkably, the GFP expression of > 99% cells was successfully knocked down by micelle-mediated siRNA interference, resulting in a decrease of two orders of magnitude in fluorescence intensity. Incorporation of PEG-CG in the micelles reduced the PEI-related cytotoxicity, and markedly enhanced the serum stability of both DNA and siRNA polyplexes. Compared with homo-PEI25, these micelles showed several advantages including the lower toxicity, higher siRNA transfection efficiency and higher polyplex stability in the presence of serum. This study therefore provides an effective approach to tune the structure, property and function of polycationic micelles for efficient DNA and siRNA delivery, which could contribute to the design and development of novel non-viral transfection vectors with superb functionality. %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2016 %J Chemiekurs der Maxim-Gorki-Gesamtschule Kleinmachnow %T Kunststoffe in der Medizin %U %X %0 conference lecture %@ %A Li, Z., Wang, W., Kratz, K., Kuechler, J., Xu, X., Zou, J., Deng, Z., Sun, X., Gossen, M., Ma, N., Lendlein, A. %D 2016 %J 35th Conference of the German Society for Clinical Microcirculation and Hemorheology %T Influence of surface roughness on neural differentiation of human induced pluripotent stem cells %U %X %0 journal article %@ 1944-8244 %A Nöchel, U., Behl, M., Balk, M., Lendlein, A. %D 2016 %J ACS Applied Materials and Interfaces %N 41 %P 28068-28076 %R doi:10.1021/acsami.6b09581 %T Thermally-Induced Triple-Shape Hydrogels: Soft Materials Enabling Complex Movements %U https://doi.org/10.1021/acsami.6b09581 41 %X Shape-memory hydrogels enable directed movements of a specimen in response to temperature, whereby crystallizable switching segments incorporated as side chains resulted in constant degrees of swelling during the shape-memory cycle. Here we report about hydrogels exhibiting a thermally induced triple-shape effect that allows complex movements of soft materials with two almost independent shape changes. Potential applications for those soft triple-shape materials are two-step self-unfolding devices or temperature-sensitive hydrogel actuators, for example, smart valves for flow rate control in aqueous media. Series of hydrogels with two different hydrophobic crystallizable switching segments were prepared. The degrees of swelling of the triple-shape hydrogels were not affected for different shapes or temperatures, which avoided in this way interferences on the shape shifts. During the two-step programming procedure, two distinct shapes can be implemented as reflected by shape fixity ratios of generally >50%. Structural analysis of the switching domains during the triple-shape cycle by means of X-ray scattering indicates that longer side chains gain lower orientation after deformation and that shorter side chains orient perpendicular to the hydrophilic main chain. Furthermore, it is observed that increased orientation of the switching domains is not a key requirement for adequate shape fixity and recovery ratios of the triple-shape effect in hydrogels, thus longer side chains can be utilized as switching segments in other shape-memory hydrogels. %0 editorial %@ 1616-5187 %A Neffe, A.T., Grijpma, D.W., Lendlein, A. %D 2016 %J Macromolecular Bioscience %N 12 %P 1743-1744 %R doi:10.1002/mabi.201600419 %T Editorial: Advanced Functional Polymers for Medicine %U https://doi.org/10.1002/mabi.201600419 12 %X No abstract %0 journal article %@ 0014-3057 %A Naolou, T., Lendlein, A., Neffe A.T. %D 2016 %J European Polymer Journal %P 139-149 %R doi:10.1016/j.eurpolymj.2016.10.011 %T Influence of metal softness on the metal-organic catalyzed polymerization of morpholin-2,5-diones to oligodepsipeptides %U https://doi.org/10.1016/j.eurpolymj.2016.10.011 %X Synthetic access to oligodepsipeptides (ODP), polymers with high potential in biomedicine, is given by the ring-opening polymerization (ROP) of morpholine-2,5-diones (MDs). Classically, the ROP of MDs is mostly conducted by coordination-insertion polymerization using metal-organics as a catalyst e.g. tin(II) di(2-ethyl hexanoate) (Sn(Oct)2). This ROP has been shown to be significantly more difficult to conduct than the corresponding ROP of dilactide, which was related to different electronic properties of the monomers and potential steric crowding. Here, we investigated the ROP of 3-(S)-sec-butylmorpholine-2,5-dione (BMD) by varying the catalyst’s hardness, comparing Sn(Oct)2 with the ethoxides of indium, magnesium, aluminum and iron(III), as well as with iron(II) acetate. The ROP of BMD with Sn(Oct)2 in bulk at 135 °C for 24 h gave ODP with a number-average molecular weight (Mn) = 4.5 kDa. Mg(OEt)2 gave the best results among the other investigated metal ethoxides with ODP of Mn = 4 kDa and a conversion ratio of 57 mol%. On the other hand, high polymerization temperature was needed (160 °C) in the case of In(OEt)3, which resulted in partial degradation, while Al(OEt)3 and Fe(OEt)3 did not result in polymerization. Very effective for the ROP of the studied MD proofed to be Fe(OAc)2, giving OBMD with a Mn = 5.8 kDa, a polydispersity of 1.1, a conversion ratio of 86 mol%, and no racemization. This catalyst likewise performed well in the polymerization of Ser- and Tyr-based MDs. Fe(II) is softer than Sn(II) and may support the ROP by promoting the alkoxide transfer step of the polymerization, while suppressing the formation of unreactive coordination complexes. In contrast, the metal alkoxides investigated were harder than Fe(II) or Sn(II), but had low steric demand. The results suggest that the hardness of the central atom is the key property in the polymerization, while steric considerations are of lower importance. In addition, a synthesis of MDs with protected side chains in improved yields was introduced. This was achieved by in situ formation of an alkyl iodide that is very effective in the ring closing reaction. %0 conference lecture %@ %A Schulz, C., Vukicevic, R., Krueger-Genge, A., Neffe, A.T., Lendlein, A., Jung, F. %D 2016 %J 18th European Conference for Clinical Hemorheology and Microcirculation, ESCHM 2016 %T Monolayer formation and shear-resistance of human umbilical vein endothelial cells on gelatin-based hydrogels with tailorable elsticity and degradability %U %X %0 conference lecture %@ %A Krueger-Genge, A., Schulz, C., Jung, F., Fuhrmann, R., Lendlein, A., Franke, R.-P. %D 2016 %J 35th Conference of the German Society for Clinical Microcirculation and Hemorheology %T Shear resistance of endothelial cells in a pathological environment %U %X %0 journal article %@ 1022-1336 %A Schoene, A.-C., Schulz, B., Lendlein, A. %D 2016 %J Macromolecular Rapid Communications %N 23 %P 1856-1859 %R doi:10.1002/marc.201600650 %T Stimuli Responsive and Multifunctional Polymers: Progress in Materials and Applications %U https://doi.org/10.1002/marc.201600650 23 %X No abstract %0 journal article %@ 1386-0291 %A Roch, T., Kratz, K., Ma, N., Lendlein, A. %D 2016 %J Clinical Hemorheology and Microcirculation %N 4 %P 899-910 %R doi:10.3233/CH-168033 %T Inflammatory responses of primary human dendritic cells towards polydimethylsiloxane and polytetrafluoroethylene %U https://doi.org/10.3233/CH-168033 4 %X Although frequently used as implants materials, both polydimethylsiloxane (PDMS) and polytetrafluoroethylene (PTFE) are often associated with adverse effects including foreign body responses. Dendritic cells (DC) are crucial for the initiation of immune reactions and could also play a role in foreign body associated inflammations. Therefore, the interaction of DC with PDMS and PTFE was investigated regarding their capacity to induce undesired cell activation. Medical grade PDMS and PTFE films were embedded into polystyrene PS inserts via injection molding to prevent the DC from migrating below the substrate and thereby, interacting not only with the test sample but also with the culture vessel material. The viability, the expression of co-stimulatory molecules, and the cytokine/chemokine profiles were determined after 24 hours incubation of the DC with PDMS or PTFE. Blank PS inserts and tissue culture polystyrene (TCP) served as reference materials. The viability of DC was not substantially influenced after incubation with PDMS and PTFE. However, both polymers induced DC activation indicated by the upregulation of co-stimulatory molecules. The release profiles of 14 soluble inflammatory mediators showed substantial differences between PDMS, PTFE, PS, and TCP. This study showed the potential of PTFE and PDMS to activate primary human dendritic cells, which could be an explanation for the often observed inflammatory events associated with the implantation of these polymers. %0 conference lecture %@ %A Roch, T., Kratz, K., Ma, N., Lendlein, A. %D 2016 %J 18th Conference of the European Society for Clinical Hemorheology and Microcirculation, ESCHM 2016 %T Inflammatory responses of primary human dendritic cells towards polydimethylsiloxane and polytetrafluoroethylene %U %X %0 journal article %@ 1386-0291 %A Xu, X., Wang, W., Li, Z., Kratz, K., Ma, N., Lendlein, A. %D 2016 %J Clinical Hemorheology and Microcirculation %N 3 %P 367-382 %R doi:10.3233/CH-168107 %T Surface geometry of poly(ether imide) boosts mouse pluripotent stem cell spontaneous cardiomyogenesis via modulating the embryoid body formation process %U https://doi.org/10.3233/CH-168107 3 %X The permanent loss of cardiomyocytes may lead to the irreversible damage of myocardium in cardiovascular diseases. The induced pluripotent stem cells (iPSCs) with the capacity of differentiation into a variety of cell types including cardiomyocytes showed high potential for efficient heart regeneration. The iPSCs and iPSC-derived embryoid bodies (EBs) as well as the differentiated cardiomyocytes are highly sensitive to the biophysical cues of their microenvironment, and accordingly their behavior and function can be largely modulated by microstructure of the cell culture surface. In this study, we investigated the regulatory effect of microscale roughness on both cardiomyogenesis and secretion of EBs using poly(ether imide) (PEI) cell culture inserts with different levels of bottom roughness (R0: flat surface; R1: rough surface, Rq ∼ 4 μm; R2: rough surface, Rq ∼ 23 μm). The proliferation rate and cardiomyogenesis of EBs increased with the increase of surface roughness. The EB secretome derived from R2 surface remarkably enhanced the in vitro new vessel formation of endothelial cells, as compared to those from R0 and R1. These findings highlight the potential to improve the iPSC/EB-based restoration of cardiovascular function via microstructured biomaterials. %0 conference lecture %@ %A Xu, X., Wang, W., Li, Z., Kratz, K., Ma, N., Lendlein, A. %D 2016 %J 35th Conference of the German Society for Clinical Microcirculation and Hemorheology %R doi:10.3233/CH-168107 %T Surface geometry of poly(ether imide) boosts mouse pluripotent stem cell spontaneous cardiomyogenesis via modulating the embryoid body formation process %U https://doi.org/10.3233/CH-168107 %X %0 journal article %@ 1386-0291 %A Li, Z., Wang, W., Kratz, K., Kuechler, J., Xu, X., Zou, J., Deng, Z., Sun, X., Gossen, M., Ma, N., Lendlein, A. %D 2016 %J Clinical Hemorheology and Microcirculation %N 3 %P 355-366 %R doi:10.3233/CH-168121 %T Influence of surface roughness on neural differentiation of human induced pluripotent stem cells %U https://doi.org/10.3233/CH-168121 3 %X Induced pluripotent stem cells (iPSCs) own the capacity to develop into all cell types of the adult body, presenting high potential in regenerative medicine. Regulating and controlling the differentiation of iPSCs using the surface topographic cues of biomaterials is a promising and safe approach to enhance their therapeutic efficacy. In this study, we tested the effects of surface roughness on differentiation of human iPSCs into neural progenitor cells and dopaminergic neuron cells using polystyrene with different roughness (R0: flat surface; R1: rough surface, Rq ∼ 6 μm; R2: rough surface, Rq ∼ 38 μm). Neural differentiation of human iPSCs could be influenced by surface roughness. Up-regulated neuronal markers were found in cells on rough surface, as examined by real-time PCR and immunostaining. Particularly, the R1 surface significantly improved the neuronal marker expression, as compared to R0 and R2 surface. This study demonstrates the significance of surface roughness, depending on the roughness level, in promoting differentiation of human iPSCs towards the neuronal lineage. Our study suggests the potential applications of surface roughness in iPSCs based treatment of neural disorder diseases, and highlights the importance of design and development of biomaterials with effective surface structures to regulate stem cells. %0 editorial %@ 0168-3659 %A Wischke, C., Ruehl, E., Lendlein, A. %D 2016 %J Journal of Controlled Release %P 1-2 %R doi:10.1016/j.jconrel.2016.10.025 %T Editorial: Dermal Drug Delivery by Nanocarriers %U https://doi.org/10.1016/j.jconrel.2016.10.025 %X No abstract %0 book part %@ %A Schroeter, M., Wildemann, B., Lendlein, A. %D 2016 %J Regenerative Medicine - From Protocol to Patient, 3. Tissue Engineering, Biomaterials and Nanotechnology %P 65-96 %R doi:10.1007/978-3-319-28274-9_4 %T Biodegradable Polymeric Materials %U https://doi.org/10.1007/978-3-319-28274-9_4 %X This chapter gives an overview about polymeric materials established in clinical use such as polyesters, polyurethanes, polyanhydrides, or carbohydrates. It describes further their synthesis and exemplary applications such as surgical sutures. Finally the importance of a continuing development of novel materials for future applications is pointed out, since the number of potential applications in the medical field is expanding rapidly. %0 journal article %@ 1022-1336 %A Roßberg, J., Rottke, F.O., Schulz, B., Lendlein, A. %D 2016 %J Macromolecular Rapid Communications %N 23 %P 1966-1971 %R doi:10.1002/marc.201600471 %T Enzymatic Degradation of Oligo(ε‐caprolactone)s End‐Capped with Phenylboronic Acid Derivatives at the Air–Water Interface %U https://doi.org/10.1002/marc.201600471 23 %X The influence of terminal functionalization of oligo(ε-caprolactone)s (OCL) with phenylboronic acid pinacol ester or phenylboronic acid on the enzymatic degradation behavior at the air–water interface is investigated by the Langmuir monolayer degradation technique. While the unsubstituted OCL immediately degrades after injection of the enzyme lipase from Pseudomonas cepacia, enzyme molecules are incorporated into the films based on end-capped OCL before degradation. This incorporation of enzymes does not inhibit or suppress the film degradation, but retards it significantly. A specific binding of lipase to the polymer monolayer allows studying the enzymatic activity of bound proteins and the influence on the degradation process. The functionalization of a macromolecule with phenyl boronic acid groups is an approach to investigate their interactions with diol-containing biomolecules like sugars and to monitor their specified impact on the enzymatic degradation behavior at the air–water interface. %0 lecture %@ %A Schroeter, M., Lendlein, A. %D 2016 %J %T Basic Organic Chemistry %U %X %0 journal article %@ 2073-4360 %A Zharinova, E., Heuchel, M., Weigel, T., Gerber, D., Kratz, K., Lendlein, A. %D 2016 %J Polymers %N 12 %P 412 %R doi:10.3390/polym8120412 %T Water-Blown Polyurethane Foams Showing a Reversible Shape-Memory Effect %U https://doi.org/10.3390/polym8120412 12 %X Water-blown polyurethane (PU) foams are of enormous technological interest as they are widely applied in various fields, i.e., consumer goods, medicine, automotive or aerospace industries. The discovery of the one-way shape-memory effect in PU foams provided a fresh impetus for extensive investigations on porous polymeric actuators over the past decades. High expansion ratios during the shape-recovery are of special interest when big volume changes are required, for example to fill an aneurysm during micro-invasive surgery or save space during transportation. However, the need to program the foams before each operation cycle could be a drawback impeding the entry of shape-memory polymeric (SMP) foams to our daily life. Here, we showed that a reversible shape-memory effect (rSME) is achievable for polyurethane water-blown semicrystalline foams. We selected commercially available crystallizable poly(ε-caprolactone)-diols of different molecular weight for foams synthesis, followed by investigations of morphology, thermal, thermomechanical and shape-memory properties of obtained compositions. Densities of synthesized foams varied from 110 to 180 kg∙m−3, while peak melting temperatures were composition-dependent and changed from 36 to 47 °C, while the melting temperature interval was around 15 K. All semicrystalline foams exhibited excellent one-way SME with shape-fixity ratios slightly above 100% and shape-recovery ratios from the second cycle of 99%. The composition with broad distribution of molecular weights of poly(ε-caprolactone)-diols exhibited an rSME of about 12% upon cyclic heating and cooling from Tlow = 10 °C and Thigh = 47 °C. We anticipate that our experimental study opens a field of systematic investigation of rSMEs in porous polymeric materials on macro and micro scale and extend the application of water-blown polyurethane foams to, e.g., protective covers with zero thermal expansion or even cushions adjustable to a certain body shape. %0 journal article %@ 2073-4360 %A Feng, Y., Liu, W., Ren, X., Lu, W., Guo, M., Behl, M., Lendlein, A., Zhang, W. %D 2016 %J Polymers %N 3 %P 58 %R doi:10.3390/polym8030058 %T Evaluation of Electrospun PCL-PIBMD Meshes Modified with Plasmid Complexes in Vitro and in Vivo %U https://doi.org/10.3390/polym8030058 3 %X Functional artificial vascular meshes from biodegradable polymers have been widely explored for certain tissue engineered meshes. Still, the foreign body reaction and limitation in endothelialization are challenges for such devices. Here, degradable meshes from phase-segregated multiblock copolymers consisting of poly(ε-caprolactone) (PCL) and polydepsipeptide segments are successfully prepared by electrospinning and electrospraying techniques. The pEGFP-ZNF580 plasmid microparticles (MPs-pZNF580) were loaded into the electrospun meshes to enhance endothelialization. These functional meshes were evaluated in vitro and in vivo. The adhesion and proliferation of endothelial cells on the meshes were enhanced in loaded mesh groups. Moreover, the hemocompatibility and the tissue response of the meshes were further tested. The complete tests showed that the vascular meshes modified with MPs-pZNF580 possessed satisfactory performance with an average fiber diameter of 550 ± 160 nm, tensile strength of 27 ± 3 MPa, Young’s modulus of 1. 9 ± 0.2 MPa, water contact angle of 95° ± 2°, relative cell number of 122% ± 1% after 7 days of culture, and low blood platelet adhesion as well as weak inflammatory reactions compared to control groups. %0 journal article %@ 2280-8000 %A Trajkovski, B., Petersen, A., Perka, C., Scharnagl, N., Mathew, S., Wischke, C., Lendlein, A., Duda, G.N. %D 2016 %J Journal of Applied Biomaterials & Functional Materials %N 2 %P e143-e153 %R doi:10.5301/jabfm.5000270 %T A double-layer patch design for local and controlled drug delivery as an intraoperative custom-made implant-coating technology %U https://doi.org/10.5301/jabfm.5000270 2 %X Double-layered patches with 1 layer for drug delivery and 1 as gluing interface could represent a solution for safe and controlled local drug delivery from implant surfaces or other, even biological, materials. The technology platform presented here opens the opportunity for personalized medicine by allowing local administration of drugs with customized release based on an intraoperative application. %0 conference lecture %@ %A Schulz, C., Vukicevic, R., Krueger-Genge, A., Neffe, A.T., Lendlein, A., Jung, F. %D 2016 %J 18th Conference of the European Society for Clinical Hemorheology and Microcirculation, ESCHM 2016 %T Cell layer formation and shear-resistance of human endothelial cells on gelatin-based hydrogels with tailorable elasticity %U %X %0 journal article %@ 1742-7061 %A Federico, S., Noechel, U., Loewenberg, C., Lendlein, A., Neffe, A.T. %D 2016 %J Acta Biomaterialia %P 1-10 %R doi:10.1016/j.actbio.2016.04.018 %T Supramolecular hydrogel networks formed by molecular recognition of collagen and a peptide grafted to hyaluronic acid %U https://doi.org/10.1016/j.actbio.2016.04.018 %X The extracellular matrix (ECM) is a nano-structured, highly complex hydrogel, in which the macromolecules are organized primarily by non-covalent interactions. Here, in a biomimetic approach, the decorin-derived collagen-binding peptide LSELRLHNN was grafted to hyaluronic acid (HA) in order to enable the formation of a supramolecular hydrogel network together with collagen. The storage modulus of a mixture of collagen and HA was increased by more than one order of magnitude (G′ = 157 Pa) in the presence of the HA-grafted peptide compared to a mixture of collagen and HA (G′ = 6 Pa). The collagen fibril diameter was decreased, as quantified using electron microscopy, in the presence of the HA-grafted peptide. Here, the peptide mimicked the function of decorin by spatially organizing collagen. The advantage of this approach is that the non-covalent crosslinks between collagen molecules and the HA chains created by the peptide form a reversible and dynamic hydrogel, which could be employed for a diverse range of applications in regenerative medicine. %0 journal article %@ 1386-0291 %A Kumar, R.K., Basu, S., Lemke, H.-D., Jankowski, J., Kratz, K., Lendlein, A., Tetali, S.D. %D 2016 %J Clinical Hemorheology and Microcirculation %N 4 %P 667-680 %R doi:10.3233/CH-152027 %T Effect of extracts of poly(ether imide) microparticles on cytotoxicity, ROS generation and proinflammatory effects on human monocytic (THP-1) cells %U https://doi.org/10.3233/CH-152027 4 %X examined. %0 journal article %@ 1386-0291 %A Tetali, S.D., Jankowski, V., Luetzow, K., Kratz, K., Lendlein, A., Jankowski, J. %D 2016 %J Clinical Hemorheology and Microcirculation %N 4 %P 657-665 %R doi:10.3233/CH-152026 %T Adsorption capacity of poly(ether imide) microparticles to uremic toxins %U https://doi.org/10.3233/CH-152026 4 %X Uremia is a phenomenon caused by retention of uremic toxins in the plasma due to functional impairment of kidneys in the elimination of urinary waste products. Uremia is presently treated by dialysis techniques like hemofiltration, dialysis or hemodiafiltration. However, these techniques in use are more favorable towards removing hydrophilic than hydrophobic uremic toxins. Hydrophobic uremic toxins, such as hydroxy hipuric acid (OH-HPA), phenylacetic acid (PAA), indoxyl sulfate (IDS) and p-cresylsulfate (pCRS), contribute substantially to the progression of chronic kidney disease (CKD) and cardiovascular disease. Therefore, objective of the present study is to test adsorption capacity of highly porous microparticles prepared from poly( ether imide) (PEI) as an alternative technique for the removal of uremic toxins. Two types of nanoporous, spherically shaped microparticles were prepared from PEI by a spraying/coagulation process. PEI particles were packed into a preparative HPLC column to which a mixture of the four types of uremic toxins was injected and eluted with ethanol. Eluted toxins were quantified by analytical HPLC. PEI particles were able to adsorb all four toxins, with the highest affinity for PAA and pCR. IDS and OH-HPA showed a partially non-reversible binding. In summary, PEI particles are interesting candidates to be explored for future application in CKD. %0 journal article %@ 1386-0291 %A Braune, S., Froehlich, G.M., Lendlein, A., Jung, F. %D 2016 %J Clinical Hemorheology and Microcirculation %N 4 %P 681-688 %R doi:10.3233/CH-152028 %T Effect of temperature on platelet adherence %U https://doi.org/10.3233/CH-152028 4 %X Differences in the density of adherent platelets after incubation at 22°C and 37°C occurred on PDMS and PET. Similar levels of adherent platelets were observed on the very thrombogenic PTFE. The covered surface areas per single platelet were analyzed to measure the state of platelet activation and revealed no differences between the two incubation temperatures for any of the analyzed polymers. Irrespective of the observed differences between the low and medium thrombogenic PDMS and PET and the higher variability at 22°C, the thrombogenicity of the three investigated polymers was evaluated being comparable at both incubation temperatures. %0 journal article %@ 1552-4973 %A Braune, S., Gross, M., Walter, M., Zhou, S., Dietze, S., Rutschow, S., Lendlein, A., Tschoepe, C., Jung, F. %D 2016 %J Journal of Biomedical Materials Research B %N 1 %P 210-217 %R doi:10.1002/jbm.b.33366 %T Adhesion and activation of platelets from subjects with coronary artery disease and apparently healthy individuals on biomaterials %U https://doi.org/10.1002/jbm.b.33366 1 %X On the basis of the clinical studies in patients with coronary artery disease (CAD) presenting an increased percentage of activated platelets, we hypothesized that hemocompatibility testing utilizing platelets from healthy individuals may result in an underestimation of the materials' thrombogenicity. Therefore, we investigated the interaction of polymer-based biomaterials with platelets from CAD patients in comparison to platelets from apparently healthy individuals. In vitro static thrombogenicity tests revealed that adherent platelet densities and total platelet covered areas were significantly increased for the low (polydimethylsiloxane, PDMS) and medium (Collagen) thrombogenic surfaces in the CAD group compared to the healthy subjects group. The area per single platelet—indicating the spreading and activation of the platelets—was markedly increased on PDMS treated with PRP from CAD subjects. This could not be observed for collagen or polytetrafluoroethylene (PTFE). For the latter material, platelet adhesion and surface coverage did not differ between the two groups. Irrespective of the substrate, the variability of these parameters was increased for CAD patients compared to healthy subjects. This indicates a higher reactivity of platelets from CAD patients compared to the healthy individuals. Our results revealed, for the first time, that utilizing platelets from apparently healthy donors bears the risk of underestimating the thrombogenicity of polymer-based biomaterials. %0 conference lecture (invited) %@ %A Schroeter, M., Lendlein, A. %D 2016 %J Marie-Curie Tag am Marie-Curie Gymnasium %T Polymere in der Medizin – Neue Entwicklungen bei Kunststoffen %U %X %0 journal article %@ 2059-8521 %A Vukicevic, R., Neffe, A.T., Gebauer, T., Frank, O., Schossig, M., Lendlein, A. %D 2016 %J MRS Advances %N 27 %P 1995-2001 %R doi:10.1557/adv.2016.416 %T Mechanical Properties of Architectured Gelatin-Based Hydrogels on Different Hierarchical Levels %U https://doi.org/10.1557/adv.2016.416 27 %X Preparation of three-dimensionally architectured porous biomaterials can be achieved in a one-step process by stabilizing gelatin with L-lysine diisocyanate ethyl ester (LDI) in water. The reaction of gelatin with LDI in presence of water leads to the formation of oligourea bridges between gelatin molecules and oligourea chains grafted on gelatin. The number and the length of the bridges, as well as of the grafted chains strongly depend on the concentration of the LDI used for the stabilization, and this has huge influence on the mechanical properties of the material on different hierarchical levels. Higher LDI concentrations yield materials with increased deformation resistance in tensile tests due to the higher number of covalent and physical netpoints in the material. However, mechanical properties determined on the micro-level by AFM indentation showed the opposite trend, i.e. a decrease of Young’s modulus with increasing LDI content. This was interpreted by a decreasing number of shorter oligourea bridges between gelatin chains with decreasing LDI content. %0 journal article %@ 0887-6266 %A Yan, W., Fang, L., Noechel, U., Kratz, K., Lendlein, A. %D 2016 %J Journal of Polymer Science B %N 19 %P 1935-1943 %R doi:10.1002/polb.24097 %T Influence of programming strain rates on the shape-memory performance of semicrystalline multiblock copolymers %U https://doi.org/10.1002/polb.24097 19 %X Multiblock copolymers named PCL-PIBMD consisting of crystallizable poly(ε-caprolactone) segments and crystallizable poly[oligo(3S-iso-butylmorpholine-2,5-dione)] segments coupled by trimethyl hexamethylene diisocyanate provide a versatile molecular architecture for achieving shape-memory effects (SMEs) in polymers. The mechanical properties as well as the SME performance of PCL-PIBMD can be tailored by the variation of physical parameters during programming such as deformation strain or applied temperature protocols. In this study, we explored the influence of applying different strain rates during programming on the resulting nanostructure of PCL-PIBMD. Programming was conducted at 50 °C by elongation to εm = 50% with strain rates of 1 or 10 or 50 mm min−1. The nanostructural changes were visualized by atomic force microscopy (AFM) measurements and investigated by in situ wide and small angle X-ray scattering experiments. With increasing the strain rate, a higher degree of orientation was observed in the amorphous domains. Simultaneously the strain-induced formation of new PIBMD crystals as well as the fragmentation of existing large PIBMD crystals occurred. The observed differences in shape fixity ratio and recovery stress of samples deformed with various strain rates can be attributed to their different nanostructures. The achieved findings can be relevant parameters for programming the shape-memory polymers with designed recovery forces. %0 journal article %@ 1386-0291 %A Braune, S., Basu, S., Kratz, K., Johansson, J.B., Reinthaler, M., Lendlein, A., Jung, F. %D 2016 %J Clinical Hemorheology and Microcirculation %N 3 %P 345-353 %R doi:10.3233/CH-168114 %T Strategy for the hemocompatibility testing of microparticles %U https://doi.org/10.3233/CH-168114 3 %X The reported in vitro dynamic whole blood test system allowed the sensitive analysis of the hemocompatibility of polymer-based microparticles and was successfully validated for porous PEI microparticles with different water wettabilities. Beyond the qualitative and quantitative analysis of cell-material interactions, the test also allowed the functional evaluation of platelets in whole blood. %0 journal article %@ 1386-0291 %A Kumar, R.K., Basu, S., Lemke, H.-D., Jankowski, J., Kratz, K., Lendlein, A., Tetali, S.D. %D 2016 %J Clinical Hemorheology and Microcirculation %N 4 %P 931-940 %R doi:10.3233/CH-168046 %T Influence of nanoporous poly(ether imide) particle extracts on human aortic endothelial cells (HAECs) %U https://doi.org/10.3233/CH-168046 4 %X It is essential to make sure that these synthetic polymers should not evoke any inflammatory or apoptotic response during dialysis. Therefore in our study we evaluated in vitro effect of PEI microparticle extracts in human aortic endothelial cells (HEACs) concerning toxicity, inflammation and apoptosis. No cell toxicity was observed when HAECs were treated with PEI extracts and inflammatory/apoptotic markers were not upregulated in presence of PEI extracts. Our results ensure biocompatibility of PEI particles and further hemocompatibility of particles will be tested. %0 conference lecture %@ %A Kumar, R.K., Basu, S., Lemke, H.-D., Jankowski, J., Kratz, K., Lendlein, A., Tetali, S.D. %D 2016 %J 18th Conference of the European Society for Clinical Hemorheology and Microcirculation, ESCHM 2016 %T Influence of nanoporous poly(ether imide) particle extracts on human aortic endothelial cells (HAECs) %U %X %0 journal article %@ 2059-8521 %A Jiang, Y., Fang, L., Kratz, K., Lendlein, A. %D 2016 %J MRS Advances %N 27 %P 1985-1993 %R doi:10.1557/adv.2016.389 %T Influence of Compression Direction on the Shape-Memory Effect of Micro-Cylinder Arrays Prepared from Semi-Crystalline Polymer Networks %U https://doi.org/10.1557/adv.2016.389 27 %X In this study, we explored the influence of the applied compression direction during programming, i.e. vertical compression and tilted compression, on the SME of microstructured crosslinked poly[ethylene-co-(vinyl acetate)] (cPEVA) films comprising arrays of micro-cylinders with a height of 10 µm and different diameters of 10 µm, 25 µm, and 50 µm. The shape recovery of the microstructures during heating was visualized online by optical microscopy, while atomic force microscopy (AFM) was utilized to investigate the temperature-induced shape change of single micro-cylinders. Here, the changes in micro-cylinder height and the characteristic angle θ were followed and analyzed for quantification of the shape-memory performance. Both compression modes resulted in almost flat programmed surfaces as indicated by high shape fixity ratios of R f ≥ 93±1%. A nearly complete recovery of the micro-cylinders was obtained for all investigated cPEVA samples documented by high shape recovery values of R r ≥ 97±1%, while the obtained shape change of the micro-cylinders during recovery almost reversely recalled the applied deformation during programming. The presented capability of SMP microstructured substrates to memorize the way of deformation during programming could be a new tool for controlling particular shape changes of microstructures during recovery and in such a way the generated local recovery forces can be adjusted. %0 conference poster %@ %A Zhang, N., Said, A., Wischke, C., Kral, V., Brodwolf, R., Boreham, A., Gerecke, C., Li, W., Neffe, A.T., Kleuser, B., Alexiev, U., Lendlein, A., Schaefer-Korting, M. %D 2016 %J International Conference on Dermal Drug Delivers by Nanocarrierrs, SFB Konferenz %T Composition-dependent skin penetration and toxicity of a series of poly[acrylonitrile-co-(N-vinyl pyrrolidone)] nanoparticles %U %X %0 conference poster %@ %A Brunacci, N., Naolou, T., Neffe, A.T., Wischke, C., Lendlein, A. %D 2016 %J International Conference on Dermal Drug Delivers by Nanocarrierrs, SFB Konferenz %T Evaluation of surfactants for the formation of sub-micron depsipeptide particles %U %X %0 journal article %@ 1386-0291 %A Schulz, C., Vukicevic, R., Krueger-Genge, A., Neffe, A.T., Lendlein, A., Jung, F. %D 2016 %J Clinical Hemorheology and Microcirculation %N 4 %P 699-710 %R doi:10.3233/CH-168007 %T Monolayer formation and shear-resistance of human umbilical vein endothelial cells on gelatin-based hydrogels with tailorable elsticity and degradability %U https://doi.org/10.3233/CH-168007 4 %X The formation of a functionally-confluent and shear-resistant endothelial cell monolayer on cardiovascular implants is a promising strategy to prevent thrombogenic processes after implantation. On the basis of existing studies with arterial endothelial cells adhering after two hours on gelatin-based hydrogels in marked higher numbers compared to tissue culture plates, we hypothesize that also venous endothelial cells (HUVEC) should be able to adhere and form an endothelial monolayer on these hydrogels after days. Furthermore, variation of the hydrogel composition, which slightly influences the materials elasticity and even more the degradation behaviour, should have no considerable effect on HUVEC. Therefore, the monolayer formation and shear resistance of HUVEC were explored on two gelatin-based hydrogels differing in their elasticity (Young’s moduli between 35 and 55 kPa) in comparison to a positive control (HUVEC on glass cover slips) and a negative control (HUVEC on glass cover slips activated with interleukin-1β) after 9 days of culturing. HUVEC density after 9 days of culturing under static conditions was lower on the hydrogels compared to both controls (p < 0.05 each). On G10_LNCO8 slightly more EC adhered than on G10_LNCO5. Staining of the actin cytoskeleton and VE-cadherin revealed a pronounced cell-substrate interaction while the cell-cell interaction was comparable to the controls (HUVEC on glass). The secretion of vasoactive and inflammatory mediators did not differ between the hydrogels and the controls. Adherent HUVEC seeded on the hydrogels were able to resist physiological shear forces and the release of cyto- and chemokines in response to the shear forces did not differ from controls (HUVEC on glass). Therefore, both gelatin-based hydrogels are a suitable substrate for EC and a promising candidate for cardiovascular applications. %0 journal article %@ 2059-8521 %A Balk, M., Behl, M., Noechel, U., Lendlein, A. %D 2016 %J MRS Advances %N 27 %P 2011-2017 %R doi:10.1557/adv.2016.414 %T Architectured Shape-Memory Hydrogels with Switching Segments Based on Oligo(Epsilon-caprolactone) %U https://doi.org/10.1557/adv.2016.414 27 %X Shape-memory hydrogels (SMHs) are potential candidate materials for biomedical applications as they can mimic the elastic properties of soft tissue and exhibit shape transformations at body temperature. Here we explored, whether architectured SMHs can be designed by incorporating oligo(ε-caprolactone) (OCL, = 4500 g·mol-1, T m = 54 °C) side chains as switching segment into hydrophilic polymer networks based on N-vinylpyrrolidone as backbone forming component and oligo(ethylene glycol)divinylether (OEGDVE, = 250 g·mol-1) as crosslinker. By utilizing NaCl and NaHCO3 as porogene during thermal crosslinking architectured hydrogels having pore diameters between 30 and 500 µm and wall thicknesses ranging from 10 to 190 µm in the swollen state were synthesized. According to the porous microstructure, a macroscopic form stability was obtained when the polymer networks were swollen until equilibrium in water. Material properties were investigated as function of the OCL content, which was varied between 20 and 40 wt%. In compression experiments the architectured hydrogels exhibited strain fixity and strain recovery ratios above 80%. These architectured SMHs might enable biomaterial applications as smart implants with the recovery of bulky structures from compact shapes. %0 journal article %@ 1838-7640 %A Tondera, C., Hauser, S., Krueger-Genge, A., Jung, F., Neffe, A.T., Lendlein, A., Klopfleisch, R., Steinbach, J., Neuber, C., Pietzsch, J. %D 2016 %J Theranostics %N 12 %P 2114-2128 %R doi:10.7150/thno.16614 %T Gelatin-based Hydrogel Degradation and Tissue Interaction in vivo: Insights from Multimodal Preclinical Imaging in Immunocompetent Nude Mice %U https://doi.org/10.7150/thno.16614 12 %X Hydrogels based on gelatin have evolved as promising multifunctional biomaterials. Gelatin is crosslinked with lysine diisocyanate ethyl ester (LDI) and the molar ratio of gelatin and LDI in the starting material mixture determines elastic properties of the resulting hydrogel. In order to investigate the clinical potential of these biopolymers, hydrogels with different ratios of gelatin and diisocyanate (3-fold (G10_LNCO3) and 8-fold (G10_LNCO8) molar excess of isocyanate groups) were subcutaneously implanted in mice (uni- or bilateral implantation). Degradation and biomaterial-tissue-interaction were investigated in vivo (MRI, optical imaging, PET) and ex vivo (autoradiography, histology, serum analysis). Multimodal imaging revealed that the number of covalent net points correlates well with degradation time, which allows for targeted modification of hydrogels based on properties of the tissue to be replaced. Importantly, the degradation time was also dependent on the number of implants per animal. Despite local mechanisms of tissue remodeling no adverse tissue responses could be observed neither locally nor systemically. Finally, this preclinical investigation in immunocompetent mice clearly demonstrated a complete restoration of the original healthy tissue. %0 journal article %@ 1616-5187 %A Schulz, C., Hecht, J., Krueger-Genge, A., Kratz, K., Jung, F., Lendlein, A. %D 2016 %J Macromolecular Bioscience %N 12 %P 1776-1791 %R doi:10.1002/mabi.201600319 %T Generating Aptamers Interacting with Polymeric Surfaces for Biofunctionalization %U https://doi.org/10.1002/mabi.201600319 12 %X Common strategies for biofunctionalization of surfaces comprise the immobilization of bioactive molecules used as cell-binding ligands for cell recruitment. Besides covalent binding, multivalent noncovalent physical forces between substrate and ligand are an alternative way to equip surfaces with biomacromolecules. In this study, polymer binding ligands are screened by means of a DNA-based in vitro selection process. As candidate biomaterials poly(ether imide) (PEI), polystyrene, and poly[ethylene-co-(vinyl acetate)] are selected, due to their different chemical structure, but similar macroscopic interface properties, allowing physical interaction with nucleotide bases by varying valences. Multivalent interacting aptamers are successfully enriched by SELEX method and an area-wide surface functionalization is achieved, which can be used for further binding of bioactive molecules. In vitro selection against the polymers result in thymine-dominated aptamer binding motifs. The preferential interaction with thymine is attributed to its chemical structure, connected with a decreased electrostatic repulsion of the π-system and the hydrophobic character maximizing entropy. The aptamer binding stability correlates with available valences for interaction, resulting in a more stable functionalization of PEI. %0 journal article %@ 1559-4106 %A Reinthaler, M., Braune, S., Lendlein, A., Landmesser, U., Jung, F. %D 2016 %J Biointerphases %N 2 %P 029702 %R doi:10.1116/1.4953246 %T Platelets and coronary artery disease: Interactions with the blood vessel wall and cardiovascular devices %U https://doi.org/10.1116/1.4953246 2 %X In view of the rare presence of studies concerning platelet function as risk factor in atherosclerotic patients, processes underlying thromboembolic events are reviewed in this paper. The morphology and the structural organization—membrane receptors, the open canalicular and dense tubular systems, the cytoskeleton, mitochondria, granules, lysosomes, and peroxisomes—of platelets are described. Platelet function under physiological conditions in atherosclerosis and after implantation of cardiovascular devices is summarized. %0 journal article %@ 1386-0291 %A Tzoneva, R., Uzunova, V., Apostolova, S., Krueger-Genge, A., Neffe, A.T., Jung, F., Lendlein, A. %D 2016 %J Clinical Hemorheology and Microcirculation %N 4 %P 941-949 %R doi:10.3233/CH-168040 %T Angiogenic potential of endothelial and tumor cells seeded on gelatin–based hydrogels in response to electrical stimulations %U https://doi.org/10.3233/CH-168040 4 %X Angiogenesis is one of the key processes during development, wound healing and tumor formation. Prerequisite for its existence is the presence of endogenous electrical fields (EFs) generated by active ion transport across polarized epithelia and endothelia, and appearance of the transcellular potentials. During angiogenesis cellular factor as endothelial growth factor (VEGF), synthesis of adhesive proteins and membrane metalloproteinases (MMPs) govern the angiogenic response to different external stimuli as biomaterials interactions and/or exogenous EF. Gelatin-based hydrogels with elasticities comparable to human tissues have shown to influence cell behavior as well as cell attachment, protein synthesis, VEGF and MMP’s production after the application of EF. Gelatin-based matrices with 3 (G10_LNCO3), 5 (G10_LNCO5), and 8 (G10_LNCO8) fold excess of isocyanate groups per mol of amine groups present in gelatin were used. Human umbilical endothelial cells (HUVEC) (Lonza Basel, Switzerland) and highly invasive breast cancer MDA-MB-231 cells (ATCC®HTB-26TM) were used. For an estimation of the amount of VEGF released from cells a commercially available VEGF ELISA (Thermo Fisher Scientific, Germany) kit was used. Fibronectin (FN) enzyme immunoassay (EIA) was used to analyze the secreted amount of FN by cells seeded on the materials. Secreted MMPs were analyzed by zymography. Gelatin-based hydrogels attracted HUVEC adhesion and diminished the adhesion of MDA-MB-231 cells. The applied direct current (DC) EF induced an almost 5–fold increase in VEGF production by HUVEC seeded on gelatin-based hydrogels, while in contrast, the applied EF decreased the production of VEGF by cancer cells. FN synthesis was elevated in HUVEC cells seeded on gelatin-based materials in comparison to FN synthesis by cancer cells. HUVEC seeded on gelatin hydrogels showed an expression mainly of MMP-2. The application of EF increased the production of MMP-2 in HUVEC seeded on gelatin materials. In contrast, for MDA-MB-231 the production of MMPs on gelatin materials was lower compared to control materials. With the application of EF the levels of MMP-9 decreased but MMP-2 expression raised significantly for gelatin materials. Overall, the results showed that studied gelatin materials suppressed attachment of cancerous cells, as well as suppressed their angiogenic potential revealed by decreased VEGF and MMP production. Thus, this study approved gelatin-based hydrogels with proper elasticity characteristics and different degradation behavior as useful matrices for use in vascular tissue regeneration or in restriction of tumor growth after tumor resection. %0 conference lecture %@ %A Braune, S., Basu, S., Kratz, K., Johansson, J.B., Reinthaler, M., Lendlein, A., Jung, F. %D 2016 %J 35th Conference of the German Society for Clinical Microcirculation and Hemorheology %T Strategy for the hemocompatibility testing of microparticles %U %X %0 editorial %@ 1743-5889 %A Wischke, C., Lendlein, A. %D 2016 %J Nanomedicine %N 12 %P 1507-1509 %R doi:10.2217/nnm.16.45 %T Editorial: Functional nanocarriers by miniaturization of polymeric materials %U https://doi.org/10.2217/nnm.16.45 12 %X No abstract %0 journal article %@ 2059-8521 %A Baudis, S., Balk, M., Lendlein, A., Behl, M. %D 2016 %J MRS Advances %N 27 %P 2003-2009 %R doi:10.1557/adv.2016.411 %T Robot Assisted Polyurethane Chain Extension of Dihydroxy Telechelic Depsipeptides %U https://doi.org/10.1557/adv.2016.411 27 %X Depsipeptide-based multiblock copolymers synthesized from dihydroxy telechelic oligodepsipeptide precursors are promising candidate materials for biomedical and pharmaceutical applications. High molecular weight polymers in polyaddition reactions e.g. of diols with diisocyanates can only be reached when reactive groups are equivalent and a high conversion for this step growth polymerization is obtained. However, in depsipeptide-based multiblock urethanes reported so far, the stoichiometric ratio of the diisocyanate compound exceeded the theoretical value of 100% by far. In order to investigate the influence of the dosing system in this unusual behavior of the stoichiometric reaction two dosing devices, a solid dosing unit (SDU) and a gravimetric dosing unit (GDU) were used for a gravimetric transfer of an oligo(3-sec-butylmorpholine-2.5-dione) (OBMD) as model oligodepsipeptide. The OBMD precursor, which was transferred as a solid or as a highly viscous solution, was reacted with an isomeric mixture of 2,2,4- and 2,4,4-trimethylhexamethylene diisocyanate (TMDI) as chain extender. Two series of 49 reactions were performed and the chain extension efficacy of the building block was compared between the SDU and GDU as well as with respect to the Carothers equation. When the GDU was used the chain extension yielded higher molecular weights, proving the high accuracy of the dosing device, and the molar ratio of TMDI required for the high-throughput synthesis of the depsipeptide-based multiblock copolymers was similar to depsipeptide-based multiblock copolymers created in a classical synthesis approach. %0 journal article %@ 2059-8521 %A Friess, F., Lendlein, A., Wischke, C. %D 2016 %J MRS Advances %N 27 %P 2019-2024 %R doi:10.1557/adv.2016.493 %T Two phase microfluidics with inviscid drops: Effects of total flow rate and delayed surfactant addition %U https://doi.org/10.1557/adv.2016.493 27 %X The microfluidic production of droplets is a well controllable process, which allows templating small spherical containers that can subsequently be transferred into uniformly sized polymer microgel particles by a crosslinking reaction. Recently, the per-channel production rate of N-isopropylacrylamide (NIPAAm) droplets (w-phase) dispersed in a low-viscosity fluorocarbon oil (o-phase) could be increased by a delayed surfactant addition, while maintaining the advantageous dripping regime. Here it should be evaluated, if delayed surfactant addition can be applied to enhance droplet production also for high viscosity continuous phases, which is associated with a change to an inviscid drop scenario compared to the previously used setting of viscous drops. It could be illustrated that the concept of delayed surfactant addition holds true also for viscous continuous phases and allows ∼8 fold increased flow rates in the dripping regime. Surprisingly, the droplet size increased at higher total flow rate with constant flow rate ratios of w- and o-phases, which is discussed in the light of viscous dissipation, microchannel bulging and viscosity of the continuous phase. More rigid microchannels such as from glass may allow further exploring this phenomenon in the future. %0 conference poster %@ %A Farhan, M., Noechel, U., Kratz, K., Lendlein, A. %D 2016 %J Integrating Function Into Polymers, Polydays 2016 %T Two-way shape-memory properties of surface functionalizable crosslinked crystallizable Terpolymers %U %X %0 journal article %@ 2190-4286 %A Rottke, F.O., Schulz, B., Richau, K., Kratz, K., Lendlein, A. %D 2016 %J Beilstein Journal of Nanotechnology %P 1156-1165 %R doi:10.3762/bjnano.7.107 %T An ellipsometric approach towards the description of inhomogeneous polymer-based Langmuir layers %U https://doi.org/10.3762/bjnano.7.107 %X The applicability of nulling-based ellipsometric mapping as a complementary method next to Brewster angle microscopy (BAM) and imaging ellipsometry (IE) is presented for the characterization of ultrathin films at the air–water interface. First, the methodology is demonstrated for a vertically nonmoving Langmuir layer of star-shaped, 4-arm poly(ω-pentadecalactone) (PPDL-D4). Using nulling-based ellipsometric mapping, PPDL-D4-based inhomogeneously structured morphologies with a vertical dimension in the lower nm range could be mapped. In addition to the identification of these structures, the differentiation between a monolayer and bare water was possible. Second, the potential and limitations of this method were verified by applying it to more versatile Langmuir layers of telechelic poly[(rac-lactide)-co-glycolide]-diol (PLGA). All ellipsometric maps were converted into thickness maps by introduction of the refractive index that was derived from independent ellipsometric experiments, and the result was additionally evaluated in terms of the root mean square roughness, Rq. Thereby, a three-dimensional view into the layers was enabled and morphological inhomogeneity could be quantified. %0 journal article %@ 0169-409X %A Balk, M., Behl, M., Wischke, C., Zotzmann, J., Lendlein, A. %D 2016 %J Advanced Drug Delivery Reviews %P 136-152 %R doi:10.1016/j.addr.2016.05.012 %T Recent advances in degradable lactide-based shape-memory polymers %U https://doi.org/10.1016/j.addr.2016.05.012 %X Biodegradable polymers are versatile polymeric materials that have a high potential in biomedical applications avoiding subsequent surgeries to remove, for example, an implanted device. In the past decade, significant advances have been achieved with poly(lactide acid) (PLA)-based materials, as they can be equipped with an additional functionality, that is, a shape-memory effect (SME). Shape-memory polymers (SMPs) can switch their shape in a predefined manner upon application of a specific external stimulus. Accordingly, SMPs have a high potential for applications ranging from electronic engineering, textiles, aerospace, and energy to biomedical and drug delivery fields based on the perspectives of new capabilities arising with such materials in biomedicine. This study summarizes the progress in SMPs with a particular focus on PLA, illustrates the design of suitable homo- and copolymer structures as well as the link between the (co)polymer structure and switching functionality, and describes recent advantages in the implementation of novel switching phenomena into SMP technology. %0 journal article %@ 0032-3861 %A Schoene, A.-C., Kratz, K., Schulz, B., Lendlein, A. %D 2016 %J Polymer %P 92-98 %R doi:10.1016/j.polymer.2016.09.001 %T The relevance of hydrophobic segments in multiblock copolyesterurethanes for their enzymatic degradation at the air-water interface %U https://doi.org/10.1016/j.polymer.2016.09.001 %X The interplay of an enzyme with a multiblock copolymer PDLCL containing two segments of different hydrophilicity and degradability is explored in thin films at the air-water interface. The enzymatic degradation was studied in homogenous Langmuir monolayers, which are formed when containing more than 40 wt% oligo(ε-caprolactone) (OCL). Enzymatic degradation rates were significantly reduced with increasing content of hydrophobic oligo(ω-pentadecalactone) (OPDL). The apparent deceleration of the enzymatic process is caused by smaller portion of water-soluble degradation fragments formed from degradable OCL fragments. Beside the film degradation, a second competing process occurs after adding lipase from Pseudomonas cepacia into the subphase, namely the enrichment of the lipase molecules in the polymeric monolayer. The incorporation of the lipase into the Langmuir film is experimentally revealed by concurrent surface area enlargement and by Brewster angle microscopy (BAM). Aside from the ability to provide information about the degradation behavior of polymers, the Langmuir monolayer degradation (LMD) approach enables to investigate polymer-enzyme interactions for non-degradable polymers. %0 journal article %@ 0032-3861 %A Fang, L., Yan, W., Noechel, U., Kratz, K., Lendlein, A. %D 2016 %J Polymer %P 54-62 %R doi:10.1016/j.polymer.2016.08.105 %T Programming structural functions in phase-segregated polymers by implementing a defined thermomechanical history %U https://doi.org/10.1016/j.polymer.2016.08.105 %X These findings provide insights about the structure function relation in multiblock copolymers with two crystalline phases exhibiting a temperature-memory effect by implementation of specific thermomechanical histories, which might be a general principle for tailoring other functions like mechanical strength or deformability in polymers. %0 journal article %@ 0168-3659 %A Vogt, A., Wischke, C., Neffe, A.T., Ma, N., Alexiev, U., Lendlein, A. %D 2016 %J Journal of Controlled Release %P 3-15 %R doi:10.1016/j.jconrel.2016.07.027 %T Nanocarriers for drug delivery into and through the skin - Do existing technologies match clinical challenges? %U https://doi.org/10.1016/j.jconrel.2016.07.027 %X The topical application of drug-loaded particles has been explored extensively aiming at a dermal, follicular or transdermal drug delivery. This review summarizes the present state of the field of polymeric nanocarriers for skin application, also covering methodologies to clinically characterize their interaction and penetration in skin in vivo. Furthermore, with a focus on a clinical perspective, a number of questions are addressed: How well are existing nanoparticle systems penetrating the skin? Which functions of new carrier concepts may meet the clinical requirements? To which extend will instrumental imaging techniques provide information on the biological functions of nanocarriers? Which issues have to be addressed for translating experimental concepts into a future clinical application? %0 journal article %@ 2059-8521 %A Neffe, A.T., Federico, S., Lendlein, A. %D 2016 %J MRS Advances %N 27 %P 1965-1970 %R doi:10.1557/adv.2016.266 %T Secondary Structure of Decorin-Derived Peptides in Solution %U https://doi.org/10.1557/adv.2016.266 27 %X Decorin is a small leucine-rich repeat proteoglycan supporting collagen fibril formation by controlling the rate of collagen fibrillogenesis and fibril dimensions. Peptides derived from the inner surface of decorin have been shown to bind to collagen, while peptides derived from the outer surface do not display such binding affinity. As typical secondary structural elements such as β-sheets and α-helical regions were found in the decorin X-ray crystal structure, here it was investigated by Circular Dichroism (CD) spectroscopy in solution, whether the same structural elements can be found in the derived peptides. Here it is shown that the peptide derived from decorin’s outer surface has the propensity to adopt helical conformation, as it was found in the crystal structure. The results were more pronounced in 80 vol% TFE solution, which led to an increase in the number as well as the length of helices. In contrast, peptides derived from the inner surface had a higher tendency to adopt β-sheet conformation, also in TFE, which corresponds to the conformation of the original sequence in the crystal structure of decorin. This suggests that the peptides derived from decorin adopt the structures present in the native protein. %0 journal article %@ 0141-3910 %A Schoene, A.-C., Kratz, K., Schulz, B., Lendlein, A. %D 2016 %J Polymer Degradation and Stability %P 114-121 %R doi:10.1016/j.polymdegradstab.2016.07.010 %T Polymer architecture versus chemical structure as adjusting tools for the enzymatic degradation of oligo(Epsilon-caprolactone) based films at the air-water interface %U https://doi.org/10.1016/j.polymdegradstab.2016.07.010 %X The enzymatic degradation of oligo(ε-caprolactone) (OCL) based films at the air-water interface is investigated by Langmuir monolayer degradation (LMD) experiments to elucidate the influence of the molecular architecture and of the chemical structure on the chain scission process. For that purpose, the interactions of 2D monolayers of two star-shaped poly(ε-caprolactone)s (PCLs) and three linear OCL based copolyesterurethanes (P(OCL-U)) with the lipase from Pseudomonas cepacia are evaluated in comparison to linear OCL. While the architecture of star-shaped PCL Langmuir layers slightly influences their degradability compared to OCL films, significantly retarded degradations are observed for P(OCL-U) films containing urethane junction units derived from 2, 2 (4), 4-trimethyl hexamethylene diisocyanate (TMDI), hexamethylene diisocyanate (HDI) or lysine ethyl ester diisocyanate (LDI). The enzymatic degradation of the OCL based 2D structures is related to the presence of hydrophilic groups within the macromolecules rather than to the packing density of the film or to the molecular weight. The results reveal that the LMD technique allows the parallel analysis of both the film/enzyme interactions and the degradation process on the molecular level. %0 journal article %@ 0024-9297 %A Bilici, C., Can, V., Noechel, U., Behl, M., Lendlein, A., Okay, O. %D 2016 %J Macromolecules %N 19 %P 7442-7449 %R doi:10.1021/acs.macromol.6b01539 %T Melt-Processable Shape-Memory Hydrogels with Self-Healing Ability of High Mechanical Strength %U https://doi.org/10.1021/acs.macromol.6b01539 19 %X We present here a synthetic strategy for the preparation of melt-processable shape-memory hydrogels with self-healing ability. The supramolecular hydrogel with a water content of 60–80 wt % consists of poly(acrylic acid) chains containing 20–50 mol % crystallizable n-octadecyl acrylate (C18A) segments together with surfactant micelles. The key of our approach to render the hydrogel melt-processable is the absence of chemical cross-links and the presence of surfactant micelles. At temperatures above the melting temperature Tm of the crystalline domains of alkyl side chains, the hydrogel liquefies due to the presence of surfactant micelles effective for solubilizing the hydrophobic C18A segments. At this stage, it can easily be shaped into any desired form by pouring into molds. Cooling below Tm and removing the surfactant from the gel network results in a hydrogel of any permanent shape with a particularly high compressive strength of 90 MPa and a Young’s modulus of 26 MPa. If the hydrogel was damaged on purpose e.g. by cutting into two pieces, the extraordinary mechanical properties can completely be recovered via temperature-induced healing process. The hydrogel also exhibits a complete shape fixity ratio and a shape recovery ratio of 97 ± 2%. %0 conference poster %@ %A Liu, Y., Razzaq, M.Y., Kratz, K., Lendlein, A. %D 2016 %J Integrating Function Into Polymers, Polydays 2016 %T Two Level Shape Changes of Programmed Micro-cuboids %U %X %0 conference lecture %@ %A Tzoneva, R., Uzunova, V., Apostolova, S., Krueger-Genge, A., Neffe, A.T., Jung, F., Lendlein, A. %D 2016 %J 18th Conference of the European Society for Clinical Hemorheology and Microcirculation, ESCHM 2016 %T Angiogenic potential of endothelial and tumor cells seeded on gelatin–based hydrogels in response to electrical stimulations %U %X %0 conference lecture %@ %A Behl, M., Noechel, U., Balk, M., Lendlein, A. %D 2016 %J Shape Memory Applications, Research and Technology Symposium, SMART 2016 %T Thermally- induced Triple-shape Hydrogels %U %X %0 conference poster %@ %A Neumann, F., Balke, J., Lendlein, A., Alexiev, U., Ma, N. %D 2016 %J International Conference on Dermal Drug Delivers by Nanocarrierrs %T Investigation of the reactive oxygen species production of gold nanoparticle with controlled size %U %X and chemical property has a strong influence on mitochondrial activity and ROS production. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2016 %J 1st International Conference of Molecular Engineering of Polymers, MEP 2016 %T Designing Multifunctional Polymers for Implants %U %X %0 conference lecture %@ %A Lendlein, A., Neffe, A.T., Ma, N., Behl, M., Wischke, C. %D 2016 %J Multifunctional Biomaterials for Medicine, HVI Symposium 2016 %T Functional Polymers and Carriers Systems %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2016 %J Advanced Functional Polymers for Medicine, AFPM 2016 %T Multifunctional Bio-based Polymers %U %X %0 conference poster %@ %A Brunacci, N., Naolou, T., Wischke, C., Neffe, A., Lendlein, A. %D 2016 %J Polydays 2016 %T Depsipeptide submicron particles of different sizes as drug delivery systems %U %X %0 conference poster %@ %A Blocki, A., Loewenberg, C., Neffe, A.T., Jung, F., Lendlein, A. %D 2016 %J Advanced Functional Polymers for Medicine, AFPM 2016 %T Mechanobiological response of encapsulated cells to a gelatin matrix with varied crosslinking density %U %X %0 conference poster %@ %A Blocki, A., Loewenberg, C., Jiang, Y., Kratz, K., Neffe, A.T., Jung, F., Lendlein, A. %D 2016 %J RegMed Forum - 10 Jahre BCRT %T Response of encapsulated cells to a gelatin matrix with varied bulk and microenvironmental elastic properties %U %X %0 conference lecture %@ %A Wischke, C., Seifert, B., Lendlein, A. %D 2016 %J Materialien fuer medizinische Anwendungen, RMIB-AG %T Sterilisation von Polymeren %U %X %0 journal article %@ 1022-1336 %A Zhang, P., Behl, M., Peng, X., Razzaq, M., Lendlein, A. %D 2016 %J Macromolecular Rapid Communications %N 23 %P 1897-1903 %R doi:10.1002/marc.201600439 %T Ultrasonic Cavitation Induced Shape-Memory Effect in Porous Polymer Networks %U https://doi.org/10.1002/marc.201600439 23 %X Inspired by the application of ultrasonic cavitation based mechanical force (CMF) to open small channels in natural soft materials (skin or tissue), it is explored whether an artificial polymer network can be created, in which shape-changes can be induced by CMF. This concept comprises an interconnected macroporous rhodium-phosphine (Rh-P) coordination polymer network, in which a CMF can reversibly dissociate the Rh-P microphases. In this way, the ligand exchange of Rh-P coordination bonds in the polymer network is accelerated, resulting in a topological rearrangement of molecular switches. This rearrangement of molecular switches enables the polymer network to release internal tension under ultrasound exposure, resulting in a CMF-induced shape-memory capability. The interconnected macroporous structure with thin pore walls is essential for allowing the CMF to effectively permeate throughout the polymer network. Potential applications of this CMF-induced shape-memory polymer can be mechanosensors or ultrasound controlled switches. %0 conference lecture (invited) %@ %A Behl, M., Lendlein, A. %D 2016 %J Medizin Innovativ - MedTech Summit 2016 %T Bedeutung von Materialinnovationen für Gesundheit und Lebensqualität %U %X %0 conference poster %@ %A Kumar Reddi, K., Krishna D., Jankowski, J., Heuchel, M., Kratz, K., Lendlein, A., Tetali, S. %D 2016 %J 35. Jahrestagung der Deutschen Gesellschaft für klinische Mikrozirkulation und Hämorheologie (DGKMH) %T Influence of extracts from hydrophilic modified poly(ether imide) microparticles on cytotoxicity; ROS generation and proinflammatory behavior of human monocytic (THP-1) cells %U %X %0 conference poster %@ %A Rottke, F.O., Schulz, B., Eidner, S., Kumke, M.U., Domb, A., Lendlein, A. %D 2016 %J Integrating function into polymers, Polydays 2016 %T Properties of poly(sebacic acid) monolayers at the air-water interface %U %X %0 conference lecture %@ %A Blocki, A., Koch, M., Beyer, S., Lendlein, A., Jung, F. %D 2016 %J 35. Jahrestagung der Deutschen Gesellschaft für klinische Mikrozirkulation und Hämorheologie (DGKMH) %T Angiogenesis during wound healing: an in vitro model %U %X %0 conference lecture (invited) %@ %A Behl, M., Neffe, A., Kratz, K., Ma, N., Lendlein, A. %D 2016 %J Medtec Europe %T Design Principles of Multifunctional Materials Interacting With Cells %U %X %0 conference lecture %@ %A Neffe, A., Federico, S., Piluso, S., Löwenberg, C., Pierce, B., Nöchel, U., Wischke, C., Lendlein, A. %D 2016 %J Polydays 2016 %T Design Strategy for the Elucidation of Protein-Protein-Binding Epitopes; and Application of the Derived Peptides in Biomaterials %U %X %0 conference lecture %@ %A Tondera, C., Ullm, S., Krüger-Genge, A., Jung, F., Gebauer, T., Neffe, A., Lendlein, A., Steinbach, J., Pietzsch, J. %D 2016 %J World Biomaterials Congress (WBC 2016) %T Gelatin-based hydrogels as versatile tools for tissue engineering: insights from multimodal imaging in vivo and ex vivo %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2016 %J Shape Memory Applications; Research and Technology Symposium - SMART 2016 %T Shape-memory effects in polymer networks %U %X %0 conference lecture %@ %A Neffe, A., Pierce, B., Tronci, G., Ma, N., Pittermann, E., Gebauer, T., Frank, O., Schossig, M., Xu, X., Willie, B., Forner, M., Ellinghaus, A., Lienau, J., Duda, G., Lendlein, A. %D 2016 %J RegMed Forum & 10 Years BCRT %T One step creation of multifunctional 3D architectured hydrogels inducing bone regeneration %U %X %0 conference lecture %@ %A Roch, T., Schroeter, M., Lendlein, A. %D 2016 %J Besuch einer Schülergruppe des Weinberg Gymnasiums am Institut für Biomaterialforschung %T Polymere als Biomaterialien %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2016 %J Marie Curie-Tag 2016; Marie-Curie-Gymnasium Ludwigsfelde %T Kunststoffe in der Medizin %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2016 %J Berufsorientierungstag des Weinberg-Gymnasiums Kleinmachnow %T HZG in Teltow und Kunststoffe in der Medizin %U %X %0 conference lecture %@ %A Lendlein, A., Schroeter, M. %D 2016 %J Tag der Wissenschaften 2016 am Weinberg-Gymnasium Kleinmachnow %T Chemie ist nicht nur wenn es knallt und stinkt! Intelligente Kunststoffe : Chemische Stimuli und deren Anwendung %U %X %0 conference lecture %@ %A Lendlein, A. %D 2016 %J RegMed Forum - 10 Jahre BCRT %T Biomaterials and Translational Technologies %U %X %0 conference lecture %@ %A Wischke, C., Kratz, K., Lendlein, A. %D 2016 %J International Conference on Molecular Interaction Engineering, MIE 2016 %T Functional Materials and Interfaces %U %X %0 conference poster %@ %A Mazurek-Budzynska, M., Razzaq, M.Y., Tomczyk, K., Rokicki, G., Behl, M., Lendlein, A. %D 2016 %J Integrating function into polymers, Polydays 2016 %T High-strain shape-memory effect of poly(carbonate-urea-urethane) networks %U %X %0 conference lecture %@ %A Roch, T., Kratz, K., Ma, N., Lendlein, A. %D 2016 %J Multifunctional Biomaterials for Medicine, HVI Symposium 2016 %T Dendritic cell responses towards clinically used polydimethylsiloxane and polytetrafluoroethylene %U %X %0 conference poster %@ %A Schoene, A.-C., Schulz, B., Lendlein, A. %D 2016 %J Integrating function into polymers, Polydays 2016 %T Enzymatic degradation of oligo(Epsilon-caprolactone) based Langmuir films adjusted by variation of polymer structure %U %X %0 conference lecture %@ %A Maier, A., Braune, S., Lendlein, A., Jung, F. %D 2016 %J 35th Conference of the German Society for Clinical Microcirculation and Hemorheology %T Adsorption and conformational changes of the human von Willebrand factor on polymer-based biomaterials %U %X %0 conference poster %@ %A Yan, W., Behl, M., Kratz, K., Lendlein, A. %D 2016 %J Integrating function into polymers, Polydays 2016 %T Insights in the shape-memory mechanism of multiblock copolymers having crystallizable as well as glassy switching segments %U %X %0 conference poster %@ %A Bhuvanesh, T., Saretia, S., Roch, T., Schoene, A.-C., Rottke, F., Ma, N., Schulz, B., Lendlein, A. %D 2016 %J Multifunctional Biomaterials for Medicine, HVI Symposium 2016 %T Langmuir-Schaefer films of fibronectin as designed biointerfaces for culturing stem cells %U %X %0 conference poster %@ %A Balk, M., Behl, M., Yang, J., Li, Q., Wischke, C., Feng, Y., Lendlein, A. %D 2016 %J Integrating function into polymers, Polydays 2016 %T Design of Polycationic Micelles by Self-Assembly of Polyethyleneimine Functionalized Oligo[(ε-aprolactone)-co-glycolide] ABA Block Copolymers %U %X %0 conference lecture %@ %A Kratz, K., Noechel, U., Behl, M., Lendlein, A. %D 2016 %J Shape Memory Applications, Research and Technology Symposium, SMART 2016 %T Decoding Temperature - Memory Effects in Copolymer Networks Having Crystallizable Controlling Units %U %X %0 conference lecture %@ %A Balk, M., Behl, M., Noechel, U., Lendlein, A. %D 2016 %J Shape Memory Applications, Research and Technology Symposium, SMART 2016 %T 3D Structured Hydrogels with Enzymatically-Induced Shape Shifting %U %X %0 conference lecture (invited) %@ %A Schulz, B., Lendlein, A. %D 2016 %J Kunststoffe & Chemie, Cross-Innovation-Workshop %T Zweidimensionale Polymerfilme an der Wasser-Luft Grenzflaeche - Chancen zur Untersuchung der Morphologie und des Abbauverhaltens von Biomaterialoberflaechen %U %X %0 conference poster %@ %A Xu, X., Li, Z., Wang, W., Kratz, K., Ma, N., Lendlein, A. %D 2016 %J 18th Conference of the European Society for Clinical Hemorheology and Microcirculation, ESCHM 2016 %T Geometry of Microwells modulate IL-6 secretion of human adipose derived mesenchymal stem cells via ROCK signaling pathway %U %X %0 conference lecture %@ %A Maier, A., Braune, S., Lendlein, A., Jung, F. %D 2016 %J Multifunctional Biomaterials for Medicine, HVI Symposium 2016 %T Adsorption and conformational changes of the human von Willebrand factor on polymer-based biomaterials %U %X %0 conference lecture %@ %A Balk, M., Behl, M., Nöchel, U., Lendlein, A. %D 2015 %J MRS Fall Meeting 2015 - Multifunctionality in Polymer-Based Materials; Gels and Interfaces %T 3D Structured Shape-Memory Hydrogels with Switching Segments Based on Oligo (ε-caprolactone) %U %X %0 journal article %@ 1946-4274 %A Stoermann, F., Wischke, C., Lendlein, A. %D 2015 %J MRS Online Proceedings Library %P 95-100 %R doi:10.1557/opl.2015.494 %T Photo-Reversibility of Cinnamylidene Acetic Acid Derived Crosslinks in Poly(ε-caprolactone) Networks %U https://doi.org/10.1557/opl.2015.494 %X Photoswitchable polymeric materials comprise moieties that undergo light-induced chemical reactions or conformational alteration. The reversibility of photo-responsive molecular switches has an influence on material functions observed on the macroscopic level such as reversibility of shape switching, especially with regard to the number of cycles. Cinnamylidene acetic acid (CAA) has received attention due to its reversible dimerization by [2+2] cycloaddition reactions. In the present study, possible side-reactions during photo-scission of the CAA dimers as netpoints in poly(ε-caprolactone) based materials were studied by fluorescence spectroscopy, HPLC and 1H,1H-COSY. Liberation of fluorescent fragments, which have their origin in the various dimer structures, could only be found in small amounts, while a non-identified species seems to be generated during dimerization and photo-scission. The results furthermore suggest that CAA-based switches in PCL-networks do not provide full reversibility of netpoint formation under the examined conditions, due to non-selective side-reactions, which could lead to an attenuation of the macroscopic effect in multiple photo-cycles. In perspective, the design of CAA derivatives with enhanced photo-reversibility should be targeted. %0 journal article %@ 0391-3988 %A Braune, S., Zhou, S., Groth, B., Lendlein, A., Jung, F. %D 2015 %J The International Journal of Artificial Organs %N 7 %P 345-418 %R doi:10.5301/ijao.5000417 %T Quantification of adherent platelets on biomaterials. Comparison of colorimetric and microscopic assessment %U https://doi.org/10.5301/ijao.5000417 7 %X No abstract %0 conference lecture (invited) %@ %A Behl, M., Saatchi, M., Noechel, U., Lendlein, A. %D 2015 %J 13th Int. Conference of Polymers for Advanced Technologies (PAT 2015) %T Reversible Bidirectional Shape-Memory Effect at Physiological Temperature from Oligo(epsilon-caprolactone) and n-Butyl Acrylate %U %X %0 journal article %@ 1022-1336 %A Saatchi, M., Behl, M., Noechel, U., Lendlein, A. %D 2015 %J Macromolecular Rapid Communications %N 10 %P 880-884 %R doi:10.1002/marc.201400729 %T Copolymer Networks From Oligo(Epsilon-caprolactone) and n-Butyl Acrylate Enable a Reversible Bidirectional Shape-Memory Effect at Human Body Temperature %U https://doi.org/10.1002/marc.201400729 10 %X Exploiting the tremendous potential of the recently discovered reversible bidirectional shape-memory effect (rbSME) for biomedical applications requires switching temperatures in the physiological range. The recent strategy is based on the reduction of the melting temperature range (ΔT m) of the actuating oligo(ε-caprolactone) (OCL) domains in copolymer networks from OCL and n-butyl acrylate (BA), where the reversible effect can be adjusted to the human body temperature. In addition, it is investigated whether an rbSME in the temperature range close or even above Tm,offset (end of the melting transition) can be obtained. Two series of networks having mixtures of OCLs reveal broad ΔTms from 2 °C to 50 °C and from −10 °C to 37 °C, respectively. In cyclic, thermomechanical experiments the rbSME can be tailored to display pronounced actuation in a temperature interval between 20 °C and 37 °C. In this way, the application spectrum of the rbSME can be extended to biomedical applications. %0 journal article %@ 0378-5173 %A Staufenbiel, S., Merino, M., Li, W., Huang, M.-D., Baudis, S., Lendlein, A., Mueller, R.H., Wischke, C. %D 2015 %J International Journal of Pharmaceutics %N 1-2 %P 87-96 %R doi:10.1016/j.ijpharm.2015.02.072 %T Surface characterization and protein interaction of a series of model poly[acrylonitrile-co-(N-vinyl pyrrolidone)] nanocarriers for drug targeting %U https://doi.org/10.1016/j.ijpharm.2015.02.072 1-2 %X The surface properties of intravenously injected nanoparticles determine the acquired blood protein adsorption pattern and subsequently the organ distribution and cellular recognition. A series of poly[acrylonitrile-co-(N-vinyl pyrrolidone)] (PANcoNVP) model nanoparticles (133–181 nm) was synthesized, in which the surface properties were altered by changing the molar content of NVP (0–33.8 mol%) as the more hydrophilic repeating unit. The extent of achieved surface property variation was comprehensively characterized. The residual sodium dodecyl sulfate (SDS) content from the synthesis was in the range 0.3–1.6 μg ml−1, potentially contributing to the surface properties. Surface hydrophobicity was determined by Rose Bengal dye adsorption, hydrophobic interaction chromatography (HIC) and aqueous two-phase partitioning (TPP). Particle charge was quantified by zeta potential (ZP) measurements including ZP–pH profiles. The interaction with proteins was analyzed by ZP measurements in serum and by adsorption studies with single proteins. Compared to hydrophobic polystyrene model nanoparticles, all PANcoNVP particles were very hydrophilic. Differences in surface hydrophobicity could be detected, which did not linearly correlate with the systematically altered bulk composition of the PANcoNVP nanoparticles. This proves the high importance of a thorough surface characterization applying a full spectrum of methods, complementing predictions solely based on bulk polymer composition. %0 conference poster %@ %A Lohmann, P., Willuweit, A., Geisler, S., Gebauer, T., Neffe, A., Lendlein, A., Shah, N., Langen, K. %D 2015 %J Konferenz der Deutschen Gesellschaft für Nuklearmedizin (DGN) %T Untersuchung der Knochenregeneration mittels 18F-Fluorid und 18F-FDG mittels Inveon PET/CT im kritischen Knochendefektmodell bei der Ratte %U %X %0 journal article %@ 1751-6161 %A Guglielmi, P.O., Herbert, E.G., Tartivel, L., Behl, M., Lendlein, A., Huber, N., Lilleodden, E.T. %D 2015 %J Journal of the Mechanical Behavior of Biomedical Materials %P 1-10 %R doi:10.1016/j.jmbbm.2015.02.009 %T Mechanical characterization of oligo(ethylene glycol)-based hydrogels by dynamic nanoindentation experiments %U https://doi.org/10.1016/j.jmbbm.2015.02.009 %X Oligo(ethylene glycol)-based (OEG) hydrogel samples of varying cross-link densities and degrees of swelling were characterized through dynamic nanoindentation testing. Experiments were performed using a non-standard nanoindentation method, which was validated on a standard polystyrene sample. This method maximizes the capability of the instrument to measure the stiffness and damping of highly compliant, viscoelastic materials. Experiments were performed over the frequency range of 1 to 50 Hz, using a 1 mm diameter flat punch indenter. A hydration method was adopted to avoid sample dehydration during testing. Values of storage modulus (E′)(E′) ranged from 3.5 to 8.9 MPa for the different OEG-hydrogel samples investigated. Samples with higher OEG concentrations showed greater scatter in the modulus measurements and it is attributed to inhomogeneities in these materials. The (E′)(E′) values did not show a strong variation over frequency for any of the samples. Values of loss modulus (E″)(E″) were two orders of magnitude lower than the storage modulus, resulting in very low values of loss factor (E″/E′E″/E′<0.1). These are characteristics of strong gels, which present negligible viscous properties. %0 journal article %@ 1386-0291 %A Yan, W., Fang, L., Heuchel, M., Kratz, K., Lendlein, A. %D 2015 %J Clinical Hemorheology and Microcirculation %N 1 %P 109-120 %R doi:10.3233/CH-151940 %T Modeling of stress relaxation of a semi-crystalline multiblock copolymer and its deformation behavior %U https://doi.org/10.3233/CH-151940 1 %X Stress relaxation can strongly influence the shape-memory capability of polymers. Recently a modified Maxwell-Wiechert model comprising two Maxwell units and single spring unit in parallel has been introduced to successfully describe the shape recovery characteristics of amorphous polyether urethanes. In this work we explored whether such a modified Maxwell-Wiechert model is capable to describe the stress relaxation behavior of a semi-crystalline multiblock copolymer named PCL-PIBMD, which consists of crystallizable poly(ε-caprolactone) (PCL) segments and crystallizable poly(3S-isobutylmorpholine-2,5-dione) (PIBMD) segments. The stress relaxation behavior of PCL-PIBMD was explored after uniaxial deformation to different strains ranging from 50 to 900% with various strain rates of 1 or 10 or 50 mm·min−1. The modeling results indicated that under the assumption that in PCL-PIBMD both PCL and PIBMD blocks have narrow molecular weight distributions and are arranged in sequence, the two relaxation processes can be related to the amorphous PCL and PIBMD domains and the spring element can be associated to the PIBMD crystalline domains. The first Maxwell unit representing the faster relaxation process characterized by the modulus E1 and the relaxation time τ1 is related to the amorphous PCL domains (which are in the rubbery state), while the second Maxwell unit (E2 ;τ2) represents the behavior of the amorphous PIBMD domains, which are in the glassy state at 50°C. Increasing strain rates resulted in an increase of E1 and a significantly reduction in τ1, whereas the elastic modulus as well as the relaxation time related to the amorphous PIBMD domains remained almost constant. When a higher deformation was applied (ε ≥ 200%) lower values for the elastic moduli of the three model elements were obtained. In general the applied model was also capable to describe the relaxation behavior of PCL-PIBMD at a deformation temperature of 20°C, where additional crystalline PCL domains are existent. The presented approach using a modified Maxwell-Wiechert model to analyze the stress relaxation behavior can be useful to understand the changes in structure-function relation of amorphous as well as semi-crystalline polymers occurring during its uniaxial deformation. %0 journal article %@ 1386-0291 %A Fang, L., Wischke, C., Kratz, K., Lendlein, A. %D 2015 %J Clinical Hemorheology and Microcirculation %N 1 %P 77-87 %R doi:10.3233/CH-151934 %T Influence of film thickness on the crystalline morphology of a copolyesterurethane comprising crystallizable poly(Epsilon-caprolactone) soft segments %U https://doi.org/10.3233/CH-151934 1 %X BACKGROUND: In this work a model approach to investigate changes in crystalline morphology during heating/cooling procedures in the context of programming and induction of the shape-memory effect is presented. OBJECTIVE AND METHOD: Atomic-force microscopy (AFM) was performed to investigate the variations in poly(ε-caprolactone) (PCL) crystalline morphology in nm thin films on a silicon substrate and a film with 20 μm thickness, prepared from a copolyesterurethane (named PDLCL) consisting of crystallizable poly(ω-pentadecalactone) (PPDL) hard segments and crystallizable PCL segments forming switching domains. RESULTS: PCL crystals in switching domains melted/recrystallized repeatedly during heating/cooling cycles between 20 and 70°C, while evident variation in PPDL crystals forming hard domains remained was not observed. When film thickness was 20 nm, PCL edge-on lamellae were observed, confined in the phase-separated morphology, while flat-on PCL lamellae, which broke out from the previous phase-separated morphology, were obtained at a film thickness of 170 nm. In contrast, large PCL spherulites were observed in the 20 μm thick film. CONCLUSION: PCL crystalline morphology in PDLCL as well as the competition between crystallization and phase separation can be tailored by the film thickness and the substrate. Such AFM investigations on thin films can be a helpful approach for predicting the crystal morphology in micro-/nanoscaled objects. %0 journal article %@ 2050-7488 %A Noechel, U., Reddy, C.S., Wang, K., Cui, J., Zizak, I., Behl, M., Kratz, K., Lendlein, A. %D 2015 %J Journal of Materials Chemistry A %N 16 %P 8284-8293 %R doi:10.1039/C4TA06586G %T Nanostructural changes in crystallizable controlling units determine the temperature-memory of polymers %U https://doi.org/10.1039/C4TA06586G 16 %X Temperature-memory polymers remember the temperature, where they were deformed recently, enabled by broad thermal transitions. In this study, we explored a series of crosslinked poly[ethylene-co-(vinyl acetate)] networks (cPEVAs) comprising crystallizable polyethylene (PE) controlling units exhibiting a pronounced temperature-memory effect (TME) between 16 and 99 °C related to a broad melting transition ([similar]100 °C). The nanostructural changes in such cPEVAs during programming and activation of the TME were analyzed via in situ X-ray scattering and specific annealing experiments. Different contributions to the mechanism of memorizing high or low deformation temperatures (Tdeform) were observed in cPEVA, which can be associated to the average PE crystal sizes. At high deformation temperatures (>50 °C), newly formed PE crystals, which are established during cooling when fixing the temporary shape, dominated the TME mechanism. In contrast, at low Tdeform (<50 °C), corresponding to a cold drawing scenario, the deformation led preferably to a disruption of existing large crystals into smaller ones, which then fix the temporary shape upon cooling. The observed mechanism of memorizing a deformation temperature might enable the prediction of the TME behavior and the knowledge based design of other TMPs with crystallizable controlling units. %0 journal article %@ 2192-2640 %A Li, Q., Shi, C., Zhang, W., Behl, M., Lendlein, A., Feng, Y. %D 2015 %J Advanced Healthcare Materials %N 8 %P 1225-1235 %R doi:10.1002/adhm.201400817 %T Nanoparticles Complexed with Gene Vectors to Promote Proliferation of Human Vascular Endothelial Cells %U https://doi.org/10.1002/adhm.201400817 8 %X Amphiphilic block copolymers containing biodegradable hydrophobic segments of depsipeptide based copolymers have been synthesized and explored as gene carriers for enhancing proliferation of endothelial cells in vitro. These polymers form nanoparticles (NPs) with positive charges on their surface, which could condense recombinant plasmids of enhanced green fluorescent protein plasmid and ZNF580 gene (pEGFP-ZNF580) and protect them against DNase I. ZNF580 gene is efficiently transported into EA.hy926 cells to promote their proliferation, whereby the transfection efficiency of NPs/pEGFP-ZNF580 is approximately similar to that of Lipofectamine 2000. These results indicate that the NPs might have potential as a carrier for pEGFP-ZNF580, which could support endothelialization of cardiovascular implants. %0 journal article %@ 0032-3861 %A Heuchel, M., Razzaq, M.Y., Kratz, K., Behl, M., Lendlein, A. %D 2015 %J Polymer %P 215-222 %R doi:10.1016/j.polymer.2015.03.063 %T Modeling the heat transfer in magneto-sensitive shape-memory polymer nanocomposites with dynamically changing surface area to volume ratios %U https://doi.org/10.1016/j.polymer.2015.03.063 %X Here we present a heat transfer model for predicting Tmax of SMPNCs samples with different S/V ratios when exposed to an AMF. The obtained temperature difference between sample and surrounding in an AMF of constant magnetic field strength decreases at uni-axial deformation with the square root of the stretching ratio. The model was validated with magnetically heating experiments of two different SMPNC systems (comprising crystallizable or amorphous switching segments) containing the same magnetic nanoparticles, while H was varied from 7 to 27 kA m−1 at a fixed frequency of 258 kHz. The experimentally achieved temperatures at deformations up to 50% could be predicted with a divergence below 6%. Finally the model was applied in a principle design study of a device consisting of a rolled SMPNC stripe, which was stepwise opened by increasing H. The modeling approach might be helpful to predict the temperature profiles of SMPNCs which were heated by other mechanisms, e.g., radiofrequency or near IR. %0 conference poster %@ %A Görs, J., Tartivel, L., Roch, T., Ma, N., Behl, M., Lendlein, A. %D 2015 %J Advanced Functional Polymers for Medicine (AFPM) %T Immuno-compatibility of Amphiphilic ABA Triblock Copolymer Based Hydrogel Films for Biomedical Application %U %X %0 conference poster %@ %A Schöne, A., Kratz, K., Schulz, B., Lendlein, A. %D 2015 %J 14th European Conference on Organised Films (ECOF 14) %T Enzymatic degradation of Langmuir films based on star-shaped poly(Ɛ-caprolactone) %U %X %0 journal article %@ 1438-7492 %A Zhang, Q., Sauter, T., Fang, L., Kratz, K., Lendlein, A. %D 2015 %J Macromolecular Materials and Engineering %N 5 %P 522-530 %R doi:10.1002/mame.201400267 %T Shape-Memory Capability of Copolyetheresterurethane Microparticles Prepared via Electrospraying %U https://doi.org/10.1002/mame.201400267 5 %X Multifunctional thermo-responsive and degradable microparticles exhibiting a shape-memory effect (SME) have attracted widespread interest in biomedicine as switchable delivery vehicles or microactuators. In this work almost spherical solid microparticles with an average diameter of 3.9 ± 0.9 μm are prepared via electrospraying of a copolyetheresterurethane named PDC, which is composed of crystallizable oligo(p-dioxanone) (OPDO) hard and oligo(ε-caprolactone) (OCL) switching segments. The PDC microparticles are programmed via compression at different pressures and their shape-memory capability is explored by off-line and online heating experiments. When a low programming pressure of 0.2 MPa is applied a pronounced thermally-induced shape-memory effect is achieved with a shape recovery ratio about 80%, while a high programming pressure of 100 MPa resulted in a weak shape-memory performance. Finally, it is demonstrated that an array of PDC microparticles deposited on a polypropylene (PP) substrate can be successfully programmed into a smart temporary film, which disintegrates upon heating to 60 °C. %0 conference lecture %@ %A Schulz, B., Lendlein, A. %D 2015 %J 14th European Conference on Organised Films (ECOF 14) %T Biodegradable polymers at the water-air-interface - Morphologies and degradation behavior %U %X %0 conference lecture %@ %A Roch, T., Lendlein, A. %D 2015 %J Exkursion: Biotechnologiestudenten der TU  Berlin %T Polymere als Biomaterialien %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2015 %J Girls` Day 2015; Mädchen-Zukunftstag %T Willkommen auf dem HZG Campus Teltow - Institut für Biomaterialforschung %U %X %0 conference poster %@ %A Vijaya Bhaskar, T., Roch, T., Ma, N., Kratz, K., Lendlein, A. %D 2015 %J Advanced Functional Polymers for Medicine (AFPM) %T Single and competitive protein adsorption on polymeric surfaces %U %X %0 conference poster %@ %A Wischke, C., Friess, F., Lendlein, A. %D 2015 %J Advanced Functional Polymers for Medicine (AFPM) %T Programming shape changes of shape-memory microparticles towards increased surface areas by elastic recovery of a phantom matrix %U %X %0 journal article %@ 1946-4274 %A Loewenberg, C., Julich-Gruner, K.K., Neffe, A.T.Lendlein, A. %D 2015 %J MRS Online Proceedings Library %P 76-81 %R doi:10.1557/opl.2015.491 %T Influence of glycidylmethacrylate functional groups attached to gelatin on the formation and properties of hydrogels %U https://doi.org/10.1557/opl.2015.491 %X Gelatin functionalized with glycidyl methacrylate (GMA) has been shown to allow crosslinking by photopolymerization and metathesis reaction. However, side chain functionalization of gelatin might reduce triple helicalization, which influences mechanical properties of gelatin-based polymer networks. Here, the influence of glycidylmethycrylation of gelatin on the chain organization, swelling, and mechanical properties is investigated by comparing among each other physical gels prepared from GMA-gelatin solutions of different concentrations (5-20 wt.-%) by drying and rehydration. An increase of GMA-gelatin concentration from 5 wt.-% to 20 wt.-% led to an increased density of produced gelatin films and a decreasing water uptake of the films from 1160 wt.-% to 730 wt.-%, while the storage modulus was increasing about one order of magnitude from 440 Pa to 4090 Pa. The relative single and triple helix content was not influenced by the variation of polymer concentration. %0 conference poster %@ %A Schöne, A., Schulz, B., Kratz, K., Lendlein, A. %D 2015 %J Advanced Functional Polymers for Medicine (AFPM) %T Reduced enzymatic degradation of poly( -caprolactone) based Langmuir films at the air- water interface by introduction of urethane linkers in the polymer backbone %U %X %0 conference lecture %@ %A Feng, Y., Wang, H., Lv, J., Behl, M., Lendlein, A. %D 2015 %J Advanced Functional Polymers for Medicine (AFPM) %T Biodegradable carrier/gene complexes to mediate proliferation and migration of human vascular endothelial cells %U %X %0 conference lecture (invited) %@ %A Neffe, A., Federico, S., Lendlein, A. %D 2015 %J Advanced Functional Polymers for Medicine (AFPM) %T Strategy for the Computer-assisted Design of Collagen Binding Peptides and their Application in Biomaterial Design %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2015 %J Advanced Functional Polymers for Medicine (AFPM) %T Geometry as Design Concept for active Biomaterials %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2015 %J 12. Teltower Technologie Tag – „Innovative Medizintechnik im Dreieck von Wissenschaft; Wirtschaft und Versorgung“ %T Multifunktionale Biomaterialien in Technologie und Medizin %U %X %0 conference lecture %@ %A Roch, T., Schroeter, M., Lendlein, A. %D 2015 %J Naturwissenschaftliche Tage am Schadow-Gymnasium Steglitz-Zehlendorf %T Polymere als Biomaterialien %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2015 %J Naturwissenschaftliche Tage am Schadow-Gymnasium Steglitz-Zehlendorf %T HZG in Teltow und Kunststoffe in der Medizin %U %X %0 journal article %@ 1386-0291 %A Roch, T., Ma, N., Kratz, K., Lendlein, A. %D 2015 %J Clinical Hemorheology and Microcirculation %N 1 %P 51-63 %R doi:10.3233/CH-151939 %T Cell-based detection of microbial biomaterial contaminations %U https://doi.org/10.3233/CH-151939 1 %X A major challenge in biomaterial synthesis and functionalization is the prevention of microbial contaminations such as endotoxins (lipopolysaccharides (LPS)). In addition to LPS, which are exclusively expressed by Gram negative bacteria, also other microbial products derived from fungi or Gram positive bacteria can be found as contaminations in research laboratories. Typically, the Limulus amebocyte lysate (LAL)-test is used to determine the endotoxin levels of medical devices. However, this test fails to detect material-bound LPS and other microbial contaminations and, as demonstrated in this study, detects LPS from various bacterial species with different sensitivities. In this study a cell-based assay using genetically engineered RAW macrophages, which detect not only soluble but also material-bound microbial contaminations is introduced. The sensitivity of this cell-line towards different LPS species and different heat-inactivated microbes was investigated. As proof of principle a soft hydrophobic poly(n-butyl acrylate) network (cPnBA), which may due to adhesive properties strongly bind microbes, was deliberately contaminated with heat-inactivated bacteria. While the LAL-test failed to detect the microbial contamination, the cell-based assay clearly detected material-bound microbial contaminations. Our data demonstrate that a cell-based detection system should routinely be used as supplement to the LAL-test to determine microbial contaminations of biomaterials. %0 journal article %@ 1042-7147 %A Sauter, T., Geiger, B., Kratz, K., Lendlein, A. %D 2015 %J Polymers for Advanced Technologies %N 10 %P 1209-1216 %R doi:10.1002/pat.3583 %T Encasement of metallic cardiovascular stents with endothelial cell-selective copolyetheresterurethane microfibers %U https://doi.org/10.1002/pat.3583 10 %X Cardiovascular metallic stents established in clinical application are typically coated by a thin polymeric layer on the stent struts to improve hemocompatibility, whereby often a drug is added to the coating to inhibit neointimal hyperplasia. Besides such thin film coatings recently nano/microfiber coated stents are investigated, whereby the fibrous coating was applied circumferential on stents. Here, we explored whether a thin fibrous encasement of metallic stents with preferentially longitudinal aligned fibers and different local fiber densities can be achieved by electrospinning. An elastic degradable copolyetheresterurethane, which is reported to selectively enhance the adhesion of endothelial cells, while simultaneously rejecting smooth muscle cells, was utilized for stent coating. The fibrous stent encasements were microscopically assessed regarding their single fiber diameters, fiber covered area and fiber alignment at three characteristic stent regions before and after stent expansion. Stent coatings with thicknesses in the range from 30 to 50 µm were achieved via electrospinning with 1,1,1,3,3,3-hexafluoro-2-propanol (HFP)-based polymer solution, while a mixture of HFP and formic acid as solvent resulted in encasements with a thickness below 5 µm comprising submicron sized single fibers. All polymeric encasements were mechanically stable during expansion, whereby the fibers deposited on the struts remained their position. The observed changes in fiber density and diameter indicated diverse local deformation mechanisms of the microfibers at the different regions between the struts. Based on these results it can be anticipated that the presented fibrous encasement of stents might be a promising alternative to stents with polymeric strut coatings releasing anti-proliferative drugs. %0 editorial %@ 1386-0291 %A Lendlein, A., Neffe, A.T., Jerome, C. %D 2015 %J Clinical Hemorheology and Microcirculation %N 1 %P 1-2 %R doi:10.3233/CH-151941 %T Editorial: Advanced Functional Polymers in Medicine (AFPM) %U https://doi.org/10.3233/CH-151941 1 %X No abstract %0 journal article %@ 1946-4274 %A Heuchel, M., Al-Qaisi, L., Kratz, K., Noechel, U., Behl, M., Lendlein, A. %D 2015 %J MRS Online Proceedings Library %P 127-134 %R doi:10.1557/opl.2015.527 %T Thermomechanical Characterization of a Series of Crosslinked Poly[ethylene-co-(vinyl acetate)] (PEVA) Copolymers %U https://doi.org/10.1557/opl.2015.527 %X The influence of VA content and extent of crosslinking on the appearance of the respective melting (Tm) and glass transition (Tg) as well as the thermomechanical properties of cPEVA systems could be demonstrated by discussing both DSC and DMTA results. The temperature range of mechanical stability correlates with the VA content and is determined by decreasing Tm values. The cross links do barely alter the stiffness of a PEVA up to the Tm rang, but lead to constant mechanical rigidity in the rubbery range above Tm. %0 journal article %@ 1042-7147 %A Goers, J., Roch, T., Tartivel, L., Behl, M., Ma, N., Lendlein, A. %D 2015 %J Polymers for Advanced Technologies %N 12 %P 1378-1386 %R doi:10.1002/pat.3676 %T Immuno-compatibility of amphiphilic ABA triblock copolymer-based hydrogel films for biomedical applications %U https://doi.org/10.1002/pat.3676 12 %X The protein adsorption and immuno-compatibility of hydrogels largely influence the clinical outcome in biomedical application scenarios. In this study photo-crosslinked 2-isocyanate ethyl methacrylate–functionalized oligo(ethylene glycol)–oligo(propylene glycol)–oligo(ethylene glycol) (IEMA–OEG–OPG–OEG–IEMA)-based polymer hydrogel films were explored with respect to endotoxin contaminations, intrinsic immuno-modulatory features, and protein adsorption of human fibronectin as well as serum albumin. Therefore three different hydrogel films were prepared from aqueous solutions of dimethacrylated OEG–OPG–OEG triblock copolymers (Mn = 12,700 g mol−1, 70 mol% OEG content) with varying wt% of the macromonomer (10 to 30%) resulting in polymeric networks, which differ in their crosslinking density and accordingly their physical properties. It could be shown that all three hydrogel film compositions do not cause complement and immune cell activation. The films were protein repellent, but reversible protein diffusion in and out of the hydrogel network, depending on the mesh size of the network, could be observed. In conclusion, the hydrogels can be considered as immuno-compatible, which qualifies them for biomedical applications such as drug release systems. %0 journal article %@ 1946-4274 %A Noechel, U., Kratz, K., Behl, M., Lendlein, A. %D 2015 %J MRS Online Proceedings Library %P 41-48 %R doi:10.1557/opl.2015.427 %T Relation -between Nanostructural Changes and Macroscopic Effects during Reversible Temperature-Memory Effect under Stress-Free Conditions in Semicrystalline Polymer Networks %U https://doi.org/10.1557/opl.2015.427 %X Temperature-memory effects in polymers under stress-free conditions are typically limited to one way effects. Recently, crosslinked polymer networks comprising crystallizable domains, which were capable of a reversible temperature-memory effect (rTME) under stress-free conditions, were introduced. The utilization of crystallizable actuator domains (AD) and shape determining domains (SD) where related to two different temperature ranges of a single broad melting temperature transition in case of rTME. In this study we investigated the nanostructure of crosslinked poly[ethylene-co-(vinyl acetate)] cPEVA capable of rTME in situ during actuation cycles utilizing X-ray scattering techniques and related the changes on the nanoscale to effects on the macroscopic scale. It was observed that 23% of SD obtained at a separation temperature of 75 °C gave the highest reversible strain and when exceeding 80 °C only isotropic crystallization occurred and no rTME was observed. Furthermore, distances between oriented crystalline lamellae correlated to the macroscopic actuation during heating-cooling cycles, exhibiting long-periods from 14 to 17 nm as function of temperature. %0 journal article %@ 1042-7147 %A Farhan, M., Chaganti, S.R., Noechel, U., Kratz, K., Lendlein, A. %D 2015 %J Polymers for Advanced Technologies %N 12 %P 1421-1427 %R doi:10.1002/pat.3702 %T Reversible shape-memory properties of surface functionalizable, crystallizable crosslinked terpolymers %U https://doi.org/10.1002/pat.3702 12 %X There is a high demand for polymer actuators comprising reactive groups at their surface in biotechnological or bioanalytical devices especially in microfluidics. In this work, we explored whether a thermoplastic poly[ethylene-co-(ethyl acylate)-co-(maleic anhydride)] (PEEAMA) terpolymer can be converted to a multifunctional shape-memory actuator by introducing covalent netpoints. In crosslinked PEEAMA (cPEEAMA) crystalline polyethylene (PE) domains with melting temperatures below 70°C should serve as actuation domains, responsible for the reversible shape change during cyclic heating and cooling, while higher melting PE crystals act as skeleton forming domains; finally maleic anhydride (MAH) groups enable surface modification of the polymeric substrate. cPEEAMAs with a fixed composition and various crosslink densities were prepared by thermally crosslinking of PEEAMA using different dicumyl peroxide (DCP) concentrations in the starting reaction mixture. A broad melting transition in the range of 50 to 90°C with a melting temperature interval of ∆Tm = 40°C, related to the crystalline PE domains, was observed for all polymer networks in differential scanning calorimetric experiments. Cyclic, thermomechanical uniaxial tensile tests revealed high reversible strains up to 17 ± 2%. A reversible change in long period during repetitive heating and cooling was observed in in situ small angle X-ray scattering experiments. Finally, a successful functionalization of the MAH groups at the cPEEAMA surface by reaction with ethylene diamine was confirmed by infrared spectroscopy analysis. The presented amino functionalized cPEEAMA substrates could be a candidate material for the preparation of adaptive microfluidic devices. %0 conference poster %@ %A Roch, T., Kratz, K., Ma, N., Lendlein, A. %D 2015 %J 34th Conference of the German Society for Clinical Microcirculation and Hemorheology %T Polymeric inserts differing in their chemical composition as substrates for dendritic cell cultivation %U %X %0 journal article %@ 1386-0291 %A Roch, T., Kratz, K., Ma, N., Lendlein, A. %D 2015 %J Clinical Hemorheology and Microcirculation %N 2 %P 347-357 %R doi:10.3233/CH-152004 %T Polymeric inserts differing in their chemical composition as substrates for dendritic cell cultivation %U https://doi.org/10.3233/CH-152004 2 %X Dendritic cells (DC) contribute to immunity by presenting antigens to T cells and shape the immune response by the secretion of cytokines. Due to their immune stimulatory potential DC-based therapies are promising approaches to overcome tolerance e.g. against tumors. In order to enforce the immunogenicity of DCs, they have to be matured and activated in vitro , which requires an appropriate cell culture substrate, supporting their survival expansion and activation. Since most cell culture devices are not optimized for DC growth, it is hypothesized that polymers with certain physicochemical properties can positively influence the DC cultures. With the aim to evaluate the effects that polymers with different chemical compositions have on the survival, the activation status, and the cytokine/chemokine secretion profile of DC, their interaction with polystyrene (PS), polycarbonate (PC), poly(ether imide) (PEI), and poly(styrene-co -acrylonitrile) (PSAN)-based cell culture inserts was investigated. By using this insert system, which fits exactly into 24 well cell culture plates, effects induced from the culture dish material can be excluded. The viability of untreated DC after incubation with the different inserts was not influenced by the different inserts, whereas LPS-activated DC showed an increased survival after cultivation on PC, PS, and PSAN compared to tissue culture polystyrene (TCP). The activation status of DC estimated by the expression of CD40, CD80, CD83, CD86 and HLA-DR expression was not altered by the different inserts in untreated DC but slightly reduced when LPS-activated DC were cultivated on PC, PS, PSAN, and PEI compared to TCP. For each polymeric cell culture insert a distinct cytokine profile could be observed. Since inserts with different chemical compositions of the inserts did not substantially alter the behavior of DC all insert systems could be considered as alternative substrate. The observed increased survival on some polymers, which showed in contrast to TCP a hydrophobic surface, could be beneficial for certain applications such as T cell expansion and activation. %0 conference lecture %@ %A Braune, S., Jung, F., Lendlein, A. %D 2015 %J VDI Arbeitskreis Kunststofftechnik Kunststoffe in der Medizin %T Thrombogenität und Hämokompatibilität von Biomaterialien %U %X %0 journal article %@ 1946-4274 %A Julich-Gruner, K.K., Lendlein, A., Boccaccini, A.R., Neffe, A.T. %D 2015 %J MRS Online Proceedings Library %P 82-87 %R doi:10.1557/opl.2015.492 %T Anisotropic Composites of Desaminotyrosine and Desaminotyrosyl Tyrosine Functionalized Gelatin and Bioactive Glass Microparticles %U https://doi.org/10.1557/opl.2015.492 %X Functionalization of gelatin with desaminotyrosine (DAT) and desamino tyrosyl tyrosine (DATT) has been demonstrated to allow network formation based on non-covalent interactions of the aromatic moieties. Based on the observation that the DAT(T) groups furthermore could interact with hydroxyapatite fillers, here it was investigated whether such interactions of DAT(T) could also be employed to stabilize composites formed by functionalized gelatins and bioactive glass (BG) particles. Because of sedimentation of the BG microparticles during the gelification, anisotropic composites with two distinct layers were formed. The characterization of mechanical properties by tensile tests and rheology showed that all composites of non-functionalized and DAT(T) functionalized gelatins with BG microparticles showed an increased Young’s modulus (E) up to 3 MPa, an increased storage modulus (G’) up to 100 kPa, increased tensile strength (σmax) up to 3.4 MPa, and increased loss modulus (G’’) compared to the pure matrices. As the observed effects were more pronounced in the DAT(T) functionalized gelatins compared to non-functionalized gelatins, and a much increased thermal stability of these composites was found, it is likely that there are binding interactions between the aromatic moieties and the BG microparticles. This effect open opportunities for the further development of this type of gelatin-based composites for bone regeneration applications. %0 journal article %@ 1946-4274 %A Wischke, C., Weigel, J., Lendlein, A. %D 2015 %J MRS Online Proceedings Library %P 30-35 %R doi:10.1557/opl.2015.60 %T Poly(n-butylcyanoacrylate) Nanoparticles as Carriers for Adenosine triphosphate %U https://doi.org/10.1557/opl.2015.60 %X Adenosine triphosphate (ATP) has numerous biological functions both intra- and extracellularly, including effects on the directed migration of cells with a regenerative potential in brain tissue. Therefore, carrier systems would be of interest that would be capable to be loaded with ATP and release it in a controlled manner. In the present study, poly(n-butylcyanoacrylate) (PBCA) nanoparticles as a potential carrier system were prepared by anionic polymerization using different polymerization media, which resulted in different zeta potential values and in some cases aggregation of nanoparticles. By decorating the particle surface with positively charged diethylaminoethyl dextran, multivalent ionic interaction allowed to load ATP to the nanoparticles by adsorption. In release experiments, an ATP release over 6 hours was observed. ATP-loaded nanoparticles may thus be suitable to explore biological effects of short-term ATP delivery for biomedical applications. %0 journal article %@ 1042-7147 %A Basu, S., Heuchel, M., Weigel, T., Kratz, K., Lendlein, A. %D 2015 %J Polymers for Advanced Technologies %N 12 %P 1447-1455 %R doi:10.1002/pat.3684 %T Integrated process for preparing porous, surface functionalized polyetherimide microparticles %U https://doi.org/10.1002/pat.3684 12 %X Highly porous polyetherimide (PEI) microparticles achieved by a spraying/coagulation process are candidate absorber materials for apheresis applications. Hydrophobic PEI surfaces tend to be rapidly coated with proteins when in contact with blood. Therefore, a hydrophilic modification of such particles is required. In this study, we explored the formation of porous, surface functionalized PEI microparticles by low molecular weight polyethyleneimine (Pei) or potassium hydroxide (KOH) in an integrated process combining chemical modification and particle formation. The integrated process resulted in smaller microparticles with diameters of 70 to 80 µm compared to the chemical two-step process. All particles exhibited similar bulk densities, ranging from 0.09 to 0.015 g cm−3, and average pore sizes around 180–250 nm. A successful modification of the particles' surface by both processing approaches could be confirmed by X-ray photoelectron spectroscopy measurements and microwetting experiments, where hydrophilic advancing contact angles of 57° to 64° were determined. Integrated particle processing further resulted in changes of the bulk properties, i.e. molecular weight, thermal decomposition behavior or glass transition temperature. Hydrophilic modified PEI microparticles have been successfully prepared by different approaches. In a next step their absorption capacity for uremic toxins will be investigated with regard to a potential application in blood detoxification. %0 editorial %@ 1022-1336 %A Julich-Gruner, K.K., Pandit, A., Lendlein, A. %D 2015 %J Macromolecular Rapid Communications %N 21 %P 1859-1861 %R doi:10.1002/marc.201500575 %T Editorial: Advanced Functional Polymers Addressing the Needs of Modern Medicine %U https://doi.org/10.1002/marc.201500575 21 %X No abstract %0 journal article %@ 1946-4274 %A Racheva, M., Romero, O., Julich-Gruner, K.K., Ulrich, A.S., Wischke, C., Lendlein, A. %D 2015 %J MRS Online Proceedings Library %P 36-41 %R doi:10.1557/opl.2015.260 %T Purity of mushroom tyrosinase as a biocatalyst for biomaterial synthesis affects the stability of therapeutic peptides %U https://doi.org/10.1557/opl.2015.260 %X The formation of injectable implants in the presence of cells or solutes has previously been conceptualized to be based on the selectivity of bioorthogonal chemical reactions. As an alternative approach, hydrogel network synthesis by enzymatic reactions with a typically high inherent substrate specificity and low toxicity have been repeatedly proposed, e.g. using commercial mushroom tyrosinase (MTyr), which specifically catalyzes phenol oxidation. In this study, it should be explored whether MTyr is compatible with therapeutic peptides that may be delivered from such hydrogels in the future. Based on the specificity of MTyr to phenol residues, no modification of peptides lacking the amino acid tyrosine would be expected. One example of such peptides is gramicidin S (GS), a potent antimicrobial peptide. However, when GS was incubated with commercial MTyr, peptide degradation occurred as observed by HPLC analysis. Several fragments of the peptide were detected by MALDI-TOF. Contamination of MTyr with peptidases was proven as the source of undesired peptide cleavage, which needs to be considered when preparing enzymatically crosslinked hydrogels for biomedical applications. %0 conference lecture %@ %A Vijaya Bhaskar, T.B., Ma, N., Lendlein, A., Roch, T. %D 2015 %J 34th Conference of the German Society for Clinical Microcirculation and Hemorheology %T The interaction of human macrophage subsets with silicone as a biomaterial %U %X %0 journal article %@ 1386-0291 %A Wang, W., Kratz, K., Behl, M., Yan, W., Liu, Y., Xu, X., Baudis, S., Li, Z., Kurtz, A., Lendlein, A., Ma, N. %D 2015 %J Clinical Hemorheology and Microcirculation %N 2 %P 301-321 %R doi:10.3233/CH-152001 %T The interaction of adipose-derived human mesenchymal stem cells and polyether ether ketone %U https://doi.org/10.3233/CH-152001 2 %X Polyether ether ketone (PEEK) as a high-performance, thermoplastic implant material entered the field of medical applications due to its structural function and commercial availability. In bone tissue engineering, the combination of mesenchymal stem cells (MSCs) with PEEK implants may accelerate the bone formation and promote the osseointegration between the implant and the adjacent bone tissue. In this concept the question how PEEK influences the behaviour and functions of MSCs is of great interest. Here the cellular response of human adipose-derived MSCs to PEEK was evaluated and compared to tissue culture plate (TCP) as the reference material. Viability and morphology of cells were not altered when cultured on the PEEK film. The cells on PEEK presented a high proliferation activity in spite of a relatively lower initial cell adhesion rate. There was no significant difference on cell apoptosis and senescence between the cells on PEEK and TCP. The inflammatory cytokines and VEGF secreted by the cells on these two surfaces were at similar levels. The cells on PEEK showed up-regulated BMP2 and down-regulated BMP4 and BMP6 gene expression, whereas no conspicuous differences were observed in the committed osteoblast markers (BGLAP, COL1A1 and Runx2). With osteoinduction the cells on PEEK and TCP exhibited a similar osteogenic differentiation potential. Our results demonstrate the biofunctionality of PEEK for human MSC cultivation and differentiation. Its clinical benefits in bone tissue engineering may be achieved by combining MSCs with PEEK implants. These data may also provide useful information for further modification of PEEK with chemical or physical methods to regulate the cellular processes of MSCs and to consequently improve the efficacy of MSC-PEEK based therapies. %0 conference lecture %@ %A Braune, S., Zhou, S., Groth, B., Lendlein, A., Jung, F. %D 2015 %J 42th Annual ESAO Conference, ESAO 2015 %T Quantification of adherent platelets on biomaterials. Comparison of colorimetric and microscopic assessment %U %X %0 conference lecture %@ %A Wang, W., Kratz, K., Behl, M., Yan, W., Liu, Y., Xu, X., Baudis, S., Li, Z., Kurtz, A., Lendlein, A., Ma, N. %D 2015 %J 34th Conference of the German Society for Clinical Microcirculation and Hemorheology %T The interaction of adipose-derived human mesenchymal stem cells and polyether ether ketone %U %X %0 journal article %@ 0168-3659 %A Hao, X., Lv, J., Li, Q., Fan, J., Feng, Y., Behl, M., Lendlein, A. %D 2015 %J Journal of Controlled Release %P e 123 %R doi:10.1016/j.jconrel.2015.05.207 %T REDV-linked biodegradable polymeric micelles as the transfer vector of ZNF580 for the proliferation of endothelial cells %U https://doi.org/10.1016/j.jconrel.2015.05.207 %X No abstract %0 journal article %@ 1946-4274 %A Baudis, S., Lendlein, A., Behl, M. %D 2015 %J MRS Online Proceedings Library %P 109-115 %R doi:10.1557/opl.2015.493 %T Robot Assisted Synthesis and Characterization of Polyester-based Polyurethanes %U https://doi.org/10.1557/opl.2015.493 %X Dihydroxy telechelics are precursors for the synthesis of multiblock copolymers. In order to synthesize high molecular weight polymers with good elastic properties it is necessary to gain detailed knowledge of the reaction behavior of these precursors. Therefore it was explored whether the polyaddition reaction of polyester-diols can be established in a robotic synthesizer platform to facilitate the elucidation of reaction characteristics. A series of 16 reactions was performed using a telechelic polyester and trimethylhexamethylene diisocyanate. The chain extension behavior of the building block was compared with respect to the Carothers equation. It was found, that the chain extension behavior follows the expected trend. The molecular weight of the polymers increased when the optimal ratio of reactive groups was approached. %0 journal article %@ 1946-4274 %A Razzaq, M.Y., Behl, M., Lendlein, A. %D 2015 %J MRS Online Proceedings Library %P 71-76 %R doi:10.1557/opl.2015.495 %T Thermally Controlled Shape-Memory Investigations of Nanocomposites Based on Oligo(ω-pentadecalactone) and Magnetic Nanoparticles Acting as Crosslinks %U https://doi.org/10.1557/opl.2015.495 %X Covalent integration of inorganic nanoparticles into polymer matrices leads to a homogenization of their distribution and enhances the structural properties. Here, we report on a thermally-controlled reversible shape-memory effect (R-SME) of magnetic nanocomposites under stress-controlled conditions. The magnetic nanocomposites consisted of an oligo(ω-pentadecalactone) (OPDL) matrix with covalently integrated or physically added magnetic nanoparticles (MNP). The R-SME of these materials was based on crystallization-induced elongation (CIE) and melting-induced contraction (MIC) under a constant stress in thermomechanical experiments. Furthermore, the adjustability of the recovery stress in magnetic nanocomposites as a function of MNP content was investigated. A slight increase in the recovery stress from 0.9 MPa for pure OPDL network to 1.2 MPa for H-NC containing 9 wt% of covalently integrated MNP was observed. %0 journal article %@ 1386-0291 %A Vijaya Bhaskar, T.B., Ma, N., Lendlein, A., Roch, T. %D 2015 %J Clinical Hemorheology and Microcirculation %N 2 %P 119-133 %R doi:10.3233/CH-151991 %T The interaction of human macrophage subsets with silicone as a biomaterial %U https://doi.org/10.3233/CH-151991 2 %X Conclusively, it was shown that silicone has the ability to induce a pro-inflammatory state to different magnitudes dependent on the macrophage subsets. This priming of the macrophage phenotype by silicone could explain the incidence of severe foreign body complications observed in vivo. %0 journal article %@ 1386-0291 %A Julich-Gruner, K.K., Roch, T., Ma, N., Neffe, A.T., Lendlein, A. %D 2015 %J Clinical Hemorheology and Microcirculation %N 1 %P 13-23 %R doi:10.3233/CH-151938 %T Synthesis and characterization of star-shaped oligo(ethylene glycol) with tyrosine derived moieties under variation of their molecular weight %U https://doi.org/10.3233/CH-151938 1 %X Conclusively, our data suggested that the sOEG solutions have surface active properties without inducing unwanted cellular responses, which is required e.g. in pharmaceutical applications to solubilize hydophobic substances. %0 journal article %@ 1022-1336 %A Vukicevic, R., Neffe, A.T., Luetzow, K., Pierce, B.F., Lendlein, A. %D 2015 %J Macromolecular Rapid Communications %N 21 %P 1891-1896 %R doi:10.1002/marc.201500311 %T Conditional Ultrasound Sensitivity of Poly[(N-isopropylacrylamide)-co-(vinyl imidazole)] Microgels for Controlled Lipase Release %U https://doi.org/10.1002/marc.201500311 21 %X Triggering the release of cargo from a polymer network by ultrasonication as an external, noninvasive stimulus can be an interesting concept for on-demand release. Here, it is shown that, in pH- and thermosensitive microgels, the ultrasound sensitivity of the polymer network depends on the external conditions. Crosslinked poly[(N-isopropylacrylamide)-co-(vinyl imidazole)] microgels showed a volume phase transition temperature (VPTT) of 25–50 °C, which increases with decreasing pH. Above the VPTT the polymer chains are collapsed, while below VPTT they are extended. Only in the case of maximum observed swelling, where the polymer chains are expanded, the microgels are mechanically fragmented through ultrasonication. In contrast, when the polymer chains are partially collapsed it is not possible to manipulate the microgels by ultrasound. Additionally, the ultrasound-induced on-demand release of wheat germ lipase from the microgels could be demonstrated successfully. The principle of conditional ultrasound sensitivity is likely to be general and can be used for selection of matrix–cargo combinations. %0 journal article %@ 0044-8249 %A Federico, S., Pierce, B.F., Piluso, S., Lendlein, A., Neffe, A.T. %D 2015 %J Angewandte Chemie %N 37 %P 11131-11135 %R doi:10.1002/ange.201505227 %T Design von Decorin-basierten Peptiden, die an Kollagen I binden, und ihr Potenzial als Adhaesionssequenzen in Biomaterialien %U https://doi.org/10.1002/ange.201505227 37 %X Das Nachbilden der Bindungsepitope von Protein-Protein-Wechselwirkungen mithilfe kleiner Peptide ist wichtig bei der Entwicklung modularer biomimetischer Systeme. Hier beschreiben wir eine Strategie zum Design solcher bioaktiver Peptide, ohne dass Strukturdaten des Proteinkomplexes benötigt werden, und weisen den Effekt der Inkorporierung solcher Adhäsionssequenzen in komplexen Biomaterialsystemen nach. Dazu wurde die hochrepetitive Struktur von Decorin analysiert. Für dessen innere sowie äußere Oberfläche wurden repräsentative Peptide identifiziert und synthetisiert. Nur Peptide auf Basis der inneren Oberfläche binden an Kollagen. Das Peptid mit der höchsten Bindungsaffinität für Kollagen I führte zu einer geringeren Diffusionsgeschwindigkeit eines gekuppelten Farbstoffs in einem Kollagengel. Dimere des Peptids ermöglichten eine physikalische Vernetzung von Kollagen, wodurch der Speichermodul eines Gels stark erhöht werden konnte. Dies belegt das Potenzial der Peptide für das Design von Biomaterialien für die regenerative Medizin. %0 journal article %@ 1788-618X %A Yan, W., Fang, L., Noechel, U., Kratz, K., Lendlein, A. %D 2015 %J eXPRESS Polymer Letters %N 7 %P 624-635 %R doi:10.3144/expresspolymlett.2015.58 %T Influence of deformation temperature on structural variation and shape-memory effect of a thermoplastic semi-crystalline multiblock copolymer %U https://doi.org/10.3144/expresspolymlett.2015.58 7 %X was mainly fixed by PCL crystals generated via strain-induced crystallization. %0 conference lecture %@ %A Lv, J., Hao, X., Yang, J., Feng, Y., Behl, M., Lendlein, A. %D 2015 %J 3rd Symposium on Innovative Polymers for Controlled Delivery, SIPCD 2014 %T PEI modified biodegradable complex micelles as gene transfer vector for proliferation of ECs %U %X %0 journal article %@ 0939-6411 %A Mathew, S., Baudis, S., Neffe, A.T., Behl, M., Wischke, C., Lendlein, A. %D 2015 %J European Journal of Pharmaceutics and Biopharmaceutics A %P 18-26 %R doi:10.1016/j.ejpb.2015.03.025 %T Effect of diisocyanate linkers on the degradation characteristics of copolyester urethanes as potential drug carrier matrices %U https://doi.org/10.1016/j.ejpb.2015.03.025 %X In this study, the effect of three aliphatic diisocyanate linkers, L-lysine diisocyanate ethyl ester (LDI), hexamethylene diisocyanate (HDI), and racemic 2,2,4-/2,4,4-trimethyl hexamethylene diisocyanate (TMDI), on the degradation of oligo[(rac-lactide)-co-glycolide] (64:36 mol%) based polyester urethanes (PEU) was examined. Samples were characterized for their molecular weight, mass loss, water uptake, sequence structure, and thermal and mechanical properties. Compared to non-segmented PLGA, the PEU showed higher water uptake and generally degraded faster. Interestingly, the rate of degradation was not directly correlating with the hydrophilicity of the diisocyanate moieties; instead, competing intra-/intermolecular hydrogen bonds in between urethane moieties appear to substantially decrease the rate of degradation for LDI-derived PEU. By comparing microparticles (μm) and films (mm) as matrices of different dimensions, it was shown that autocatalysis remains a contributor to degradation of the larger-sized PEU matrices as it is typical for non-segmented lactide/glycolide copolymers. The shown capacity of lactide/glycolide-based multiblock copolymers to degrade faster than PLGA and exhibit improved elastic properties could be of interest for medical implants and drug release systems. %0 journal article %@ 1022-1336 %A Schoene, A.-C., Richau, K., Kratz, K., Schulz, B., Lendlein, A. %D 2015 %J Macromolecular Rapid Communications %N 21 %P 1910-1915 %R doi:10.1002/marc.201500316 %T Influence of Diurethane Linkers on the Langmuir Layer Behavior of Oligo[(rac-lactide)-co-glycolide]-based Polyesterurethanes %U https://doi.org/10.1002/marc.201500316 21 %X Three oligo[(rac-lactide)-co-glycolide] based polyesterurethanes (OLGA-PUs) containing different diurethane linkers are investigated by the Langmuir monolayer technique and compared to poly[(rac-lactide)-co-glycolide] (PLGA) to elucidate the influence of the diurethane junction units on hydrophilicity and packing motifs of these polymers at the air–water interface. The presence of diurethane linkers does not manifest itself in the Langmuir layer behavior both in compression and expansion experiments when monomolecular films of OLGA-PUs are spread on the water surface. However, the linker retard the evolution of morphological structures at intermediate compression level under isobaric conditions (with a surface pressure greater than 11 mN m−1) compared to the PLGA, independent on the chemical structure of the diurethane moiety. The layer thicknesses of both OLGA-PU and PLGA films decrease in the high compression state with decreasing surface pressure, as deduced from ellipsometric data. All films must be described with the effective medium approximation as water swollen layers. %0 conference lecture %@ %A Behl, M., Baudis, S., Lendlein, A. %D 2015 %J MRS Fall Meeting 2015 %T Investigation of the Influence of Reaction Parameters on the Diameter of Copolymer Particles %U %X %0 journal article %@ 0168-3659 %A Lv, J., Hao, X., Yang, J., Feng, Y., Behl, M., Lendlein, A. %D 2015 %J Journal of Controlled Release %P e 60 %R doi:10.1016/j.jconrel.2015.05.099 %T PEI modified biodegradable complex micelles as gene transfer vector for proliferation of ECs %U https://doi.org/10.1016/j.jconrel.2015.05.099 %X No abstract %0 journal article %@ 1042-7147 %A Schoene, A.-C., Falkenhagen, S., Travkova, O., Schulz, B., Kratz, K., Lendlein, A. %D 2015 %J Polymers for Advanced Technologies %N 12 %P 1402-1410 %R doi:10.1002/pat.3701 %T Influence of intermediate degradation products on the hydrolytic degradation of poly[(rac-lactide)-co-glycolide] at the air–water interface %U https://doi.org/10.1002/pat.3701 12 %X The influence of intermediate degradation products on the hydrolytic degradation of poly[(rac-lactide)-co-glycolide] (PLGA, 50 mol% lactide) at the air–water interface is investigated using the Langmuir film balance. For that purpose, PLGA bulk samples were degraded in aqueous solution for different time periods to generate different sized fragments with varying water solubility. After dissolution in chloroform the water-insoluble degradation products are able to form Langmuir monolayers with an increased elasticity modulus by decreasing molecular weights. Water-soluble degradation products of PLGA were found to be surface active and form an adsorption layer at the air–water interface, which can be further compressed, and revealing a different adsorption behavior in dependence on their composition. The obtained results imply that measured surface area reduction as it is determined in Langmuir monolayer degradation (LMD) experiment is restricted by the effect of the surface activity of adsorbed oligomer fragments during the degradation process. The surface activity of the formed degradation products makes it difficult to derive degradation mechanism from a common LMD experiment. To elucidate the mechanism in detail, dimers, trimers and longer oligomers with known composition and end-groups have to be investigated. %0 journal article %@ 1042-7147 %A Zhang, Q., Kratz, K., Lendlein, A. %D 2015 %J Polymers for Advanced Technologies %N 12 %P 1468-1475 %R doi:10.1002/pat.3630 %T Shape-memory properties of degradable electrospun scaffolds based on hollow microfibers %U https://doi.org/10.1002/pat.3630 12 %X Multifunctional thermo-responsive and degradable porous materials exhibiting a shape-memory effect are explored in biomedicine as actively moving scaffolds or switchable substrates. One example are electrospun shape-memory polymer-based scaffolds comprising solid microfibers or nanofibers. In this work, we explored whether fibrous scaffolds composed of hollow microfibers can be prepared from a degradable shape-memory copolyetheresterurethane named PDC, which is composed of crystallizable oligo(p-dioxanone) (OPDO) hard and oligo(ε-caprolactone) (OCL) switching segments. Scaffolds based on PDC microfibers with identical outer diameter around 1.4 ± 0.3 µm and different hollowness of 0%, 13%, and 33% related to the outer diameter (determined by scanning electron microscopy) were prepared by coaxial electrospinning using poly(ethylene glycol) (PEG) as sacrificial core. Thermal characterization of the scaffolds by differential scanning calorimetry (DSC) and thermogravimetric analysis confirmed a successful removal of PEG. DSC results revealed that the degree of crystallinity increased with increasing microfiber hollowness. The Young's modulus and the failure stress of the prepared scaffolds determined by tensile tests at ambient temperature and 50 °C were found to increase with rising hollowness, while the elongation at break decreased. Cyclic, thermomechanical uniaxial tensile tests showed a pronounced dual-shape effect for all tested materials. Scaffolds comprising microfibers with a hollowness of 33% exhibited the highest shape recovery ratio. Here, we could demonstrate that the degree of hollowness of microfibers, which alters the degree of macromolecular chain orientation, is a suitable design parameter to tailor the mechanical properties as well as the shape-memory performance of electrospun shape-memory polymer fibrous scaffolds. %0 conference paper %@ 1946-4274 %A Lendlein, A., Tirelli, N., Weiss, R., Xie, Tao %D 2015 %J Multifunctional Polymeric and Hybrid Materials %P ix %R doi:10.1557/opl.2015.614 %T Preface: Multifunctional Polymeric and Hybrid Materials %U https://doi.org/10.1557/opl.2015.614 %X No abstract %0 conference poster %@ %A Schöne, A., Travkova, O., Falkenhagen, S., Schulz, B., Kratz, K., Lendlein, A. %D 2015 %J 14th European Conference on Organised Films (ECOF 14) %T Influence of poly[(rac-lactide)-co-glycolide] degradation fragments on hydrolytic Langmuir monolayer degradationexperiments %U %X %0 journal article %@ 1042-7147 %A Schoene, A.-C., Kratz, K., Schulz, B., Reiche, J., Santer, S., Lendlein, A. %D 2015 %J Polymers for Advanced Technologies %N 12 %P 1411-1420 %R doi:10.1002/pat.3638 %T Surface pressure-induced isothermal 2D- to 3D-transitions in Langmuir films of poly(Epsilon-caprolactone)s and oligo(Epsilon-caprolactone) based polyesterurethanes %U https://doi.org/10.1002/pat.3638 12 %X Surface pressure-induced isothermal 2D- to 3D-transitions in Langmuir films of biodegradable poly(ε-caprolactone) (PCL) and oligo(ε-caprolactone) based polyester-urethanes P(OCL-U)s are investigated in order to gain deeper insights into the influence of the linker species on the crystallization and aggregation behavior of macromolecules in a biomimetic aqueous environment. The presence of three urethane linkers derived from 2, 2 (4), 4-trimethyl-hexamethylene-diisocyanate (TMDI), hexamethylene diisocyanate (HDI) and lysine ethylester diisocyanate (LDI) induces remarkable changes in the mesoscopic structure compared to PCL Langmuir films. The pronounced changes in the morphology of the 3D structures co-existing with the Langmuir film above a collapse surface pressure are visualized by Brewster angle microscopy (BAM). Hysteresis of the compression–expansion isotherm in the surface pressure range of the 2D- to 3D-transition indicates the influence of the urethane linkers on the diffusion-limited kinetics and on the reversibility of this phase transition. %0 lecture %@ %A Lendlein, A. %D 2015 %J %T Advanced Topics in Polymer Synthesis %U %X %0 conference lecture %@ %A Braune, S., Kratz, K., Lendlein, A., Jung, F. %D 2015 %J 34. Jahrestagung der Deutschen Gesellschaft für klinische Mikrozirkulation und Hämorheologie (DGKMH) %T Strategy for the hemocompatibility testing of polymer based microparticles %U %X %0 journal article %@ 0033-4545 %A Wang, L., Baudis, S., Kratz, K., Lendlein, A. %D 2015 %J Pure and Applied Chemistry %N 11-12 %P 1085-1097 %R doi:10.1515/pac-2015-0607 %T Characterization of bi-layered magnetic nanoparticles synthesized via two-step surface-initiated ring-opening polymerization %U https://doi.org/10.1515/pac-2015-0607 11-12 %X A versatile strategy to integrate multiple functions in a polymer based material is the formation of polymer networks with defined nanostructures. Here, we present synthesis and comprehensive characterization of covalently surface functionalized magnetic nanoparticles (MNPs) comprising a bi-layer oligomeric shell, using Sn(Oct)2 as catalyst for a two-step functionalization. These hydroxy-terminated precursors for degradable magneto- and thermo-sensitive polymer networks were prepared via two subsequent surface-initiated ring-opening polymerizations (ROPs) with ω-pentadecalactone and ε-caprolactone. A two-step mass loss obtained in thermogravimetric analysis and two distinct melting transitions around 50 and 85°C observed in differential scanning calorimetry experiments, which are attributed to the melting of OPDL and OCL crystallites, confirmed a successful preparation of the modified MNPs. The oligomeric coating of the nanoparticles could be visualized by transmission electron microscopy. The investigation of degrafted oligomeric coatings by gel permeation chromatography and 1H-NMR spectroscopy showed an increase in number average molecular weight as well as the presence of signals related to both of oligo(ω-pentadecalactone) (OPDL) and oligo(ε-caprolactone) (OCL) after the second ROP. A more detailed analysis of the NMR results revealed that only a few ω-pentadecalactone repeating units are present in the degrafted oligomeric bi-layers, whereby a considerable degree of transesterification could be observed when OPDL was polymerized in the 2nd ROP step. These findings are supported by a low degree of crystallinity for OPDL in the degrafted oligomeric bi-layers obtained in wide angle X-ray scattering experiments. Based on these findings it can be concluded that Sn(Oct)2 was suitable as catalyst for the preparation of nanosized bi-layered coated MNP precursors by a two-step ROP. %0 journal article %@ 1042-7147 %A Vijaya Bhaskar, T.B., Roch, T., Romero, O., Ma, N., Kratz, K., Lendlein, A. %D 2015 %J Polymers for Advanced Technologies %N 12 %P 1387-1393 %R doi:10.1002/pat.3639 %T Single and competitive protein adsorption on polymeric surfaces %U https://doi.org/10.1002/pat.3639 12 %X The biological response to material surfaces is often influenced by protein layers formed at the bio-interface. Understanding this protein layer is of paramount importance for biomedical materials and cell culture devices, which often require protein coating for optimal cell growth. An insert system fitting exactly into standard tissue culture plates was developed and can be used for biological investigations without the influence of the cell culture material. Inserts prepared from polystyrene (PS), polycarbonate (PC), poly(styrene-co-acrylonitrile) (PSAN) and poly(ether imide) (PEI) exhibit a similar surface roughness and wettability so that only the chemistry is varied. Previously, stem cell adhesion responses were found to be different for these inserts, possibly because of their different protein adsorption profiles. This work investigated if the surface functional groups of these inserts influence their protein binding ability. Single and competitive adsorption of two most abundant blood proteins, human serum albumin (HSA) and immunoglobulin G (IgG) on these polymers was investigated by labeling both proteins with different near-infrared (IR) dyes. PEI showed the highest protein adsorption propensity in single and competitive adsorption of IgG and HSA while PS exhibited the least adsorption capability, whereas PSAN and PC showed an intermediate protein adsorption profile. Chemical inertness of PS could be the reason for this low protein binding ability and limited cell growth. Conclusively, a novel method to efficiently detect protein adsorption on polymer surfaces was established, and using this method the high relevance of the chemical composition of polymeric substrates on their protein adsorption profile could be proven. %0 conference poster %@ %A Rottke, F., Schulz, B., Richau, K., Kratz, K., Lendlein, A. %D 2015 %J 14th European Conference on Organised Films (ECOF 14) %T Visualization of inhomogeneous; biodegradable polymeric Langmuir layers by imaging ellipsometry and mapping technique %U %X %0 conference poster %@ %A Roßberg, J., Schulz, B., Wollenberger, U., Lendlein, A. %D 2015 %J 14th European Conference on Organised Films (ECOF 14 ) %T Enzymatic Langmuir monolayer degradation of phenylboronic acid end-capped oligo( -caprolactone) %U %X %0 conference poster %@ %A Neffe, A., Vukićević, R., Lützow, K., Pierce, B., Lendlein, A. %D 2015 %J 5. Int. Seminar “Advanced Functional Polymers for Medicine (AFPM)” %T Ultrasound-sensitive microparticles based on poly[(N-isopropylacrylamide)-co-(vinyl imidazole)] %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2015 %J Seminar at the School of Pharmacy; Hebrew University %T Multifunctional Bio-based Polymers in Medicine and Technology %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2015 %J Lecture at the Tianjin University %T Design of multifunctional bio-based polymers in technology and medicine %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2015 %J Symposium “Frontiers in Biomedical Polymers (FBPS)" %T Multifunctionality in Biomaterials – going beyond compromises %U %X %0 conference lecture %@ %A Krüger, A., Löwenberg, C., Neffe, A., Roch, T., Schöne, A., Schroeter, M., Viszokai, P., Vuki evi , R., Lendlein, A. %D 2015 %J Potsdamer Tag der Wissenschaften 2015 %T Biomaterialien für die Medizin %U %X %0 conference lecture %@ %A Braune, S., Jung, F., Lendlein, A. %D 2015 %J Exkursion: Biotechnologiestudenten der TU  Berlin; Prof. Lauster AG %T Hämokompatibilität / Endothelialisierung von Biomaterialien %U %X %0 conference poster %@ %A Tzoneva, R., Uzunova, V., Apostolova, S., Krüger, A., Neffe, A., Jung, F., Lendlein, A. %D 2015 %J 34. Jahrestagung der Deutschen Gesellschaft für klinische Mikrozirkulation und Hämorheologie (DGKMH) %T Effect of electrical stimulation on vascular endothelial and tumor cells on angiogenic response %U %X %0 conference poster %@ %A Rottke, F., Schulz, B., Richau, K., Kratz, K., Behl, M., Lendlein, A. %D 2015 %J 9th Workshop on Ellipsometry (WSE 2015) %T Visualization of inhomogeneous; biodegradable polymeric Langmuir AClayers by imaging ellipsometry and mapping technique %U %X %0 conference poster %@ %A Farhan, M., Kratz, K., Lendlein, A. %D 2015 %J 5. Int. Seminar “Advanced Functional Polymers for Medicine (AFPM)” %T Bidirectional Shape-memory Effect of Poly (Ɛ-caprolactone) Based Polymer Networks %U %X %0 conference poster %@ %A Zhang, Q., Kratz, K., Lendlein, A. %D 2015 %J 5. Int. Seminar “Advanced Functional Polymers for Medicine (AFPM)” %T Shape-memory properties of degradable electrospun scaffolds based on hollow microfibers %U %X %0 conference poster %@ %A Basu, S., Kratz, K., Lendlein, A. %D 2015 %J 5. Int. Seminar “Advanced Functional Polymers for Medicine (AFPM)” %T Surface modification of porous polyetherimide microparticles prepared via a spraying/coagulation process %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2015 %J Lecture at the Ben-Gurion University of the Negev %T Tailoring Properties and Functions of Bio-based Polymers %U %X %0 journal article %@ 2192-2640 %A Neffe, A.T., Lendlein, A. %D 2015 %J Advanced Healthcare Materials %N 5 %P 642-645 %R doi:10.1002/adhm.201400724 %T Going Beyond Compromises in Multifunctionality of Biomaterials %U https://doi.org/10.1002/adhm.201400724 5 %X Prioritizing one function in biomaterial and biomedical device design goes hand in hand with compromises with respect to other functions. Strategies to overcome the limitations of such an approach for realizing novel fields of biomaterial application are critically evaluated to promote interdisciplinary and integrative research. %0 conference poster %@ %A Jiang, J., Liu, Y., Seifert, B., dal Bianco, A., Wischke, C., Kratz, K., Lendlein, A. %D 2015 %J Design von Biosystemen - Vom fundamentalen Verständnis zu neuen Anwendungen %T Multifunktionale Materialien für die Biotechnologie %U %X %0 conference poster %@ %A Kumar, R., Basu, S., Kratz, K., Lendlein, A., Tetali, S. %D 2015 %J 34. Jahrestagung der Deutschen Gesellschaft für klinische Mikrozirkulation und Hämorheologie (DGKMH) %T Examining the influence of poly(etherimide) microparticles on cytotoxicity and proinflammatoryeffects on human monocytic cells as well as apoptosis of human aortic endothelial cells %U %X %0 conference lecture %@ %A Liu, Y., Fang, L., Kratz, K., Lendlein, A. %D 2015 %J MRS Fall Meeting 2015; Symposium H “Multifunctionality in Polymer-Based Materials; Gels and Interfaces” %T Preparation and characterization of polymer-based cubic micro actuators %U %X %0 conference lecture %@ %A Jiang, Y., Fang, L., Kratz, K., Lendlein, A. %D 2015 %J MRS Fall Meeting 2015; Symposium H “Multifunctionality in Polymer-Based Materials; Gels and Interfaces” %T Temperature-Memory Polymers as Active Substrates for Printable Biology on 3D Structures %U %X %0 conference lecture %@ %A Yan, W., Fang, L., Nöchel, U., Kratz, K., Lendlein, A. %D 2015 %J MRS Fall Meeting 2015; Symposium H “Multifunctionality in Polymer-Based Materials; Gels and Interfaces” %T Effect of Strain Rate on the Nanostructure and Shape-Memory Properties of Semi-crystallineMultiblock Copolymers %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2015 %J 13th Int. Conference of Polymers for Advanced Technologies (PAT 2015) %T Multifunctional Bio-based Polymers in Technology and Medicine %U %X %0 journal article %@ 0021-9797 %A Seiffert, S., Friess, F., Lendlein, A., Wischke, C. %D 2015 %J Journal of Colloid and Interface Science %P 38-42 %R doi:10.1016/j.jcis.2015.04.017 %T Faster Droplet Production by Delayed Surfactant-Addition in Two-Phase Microfluidics to form Thermo-Sensitive Microgels %U https://doi.org/10.1016/j.jcis.2015.04.017 %X Microfluidic droplet templating produces monodisperse particles of well controllable sizes, but this is limited by the necessity to operate microfluidic devices at low flow rates in the dripping regime. Here, the per-channel rate of droplet production could be substantially increased by delayed surfactant addition as applied and verified for microfluidic production of N-isopropylacrylamide based microgels. %0 conference poster %@ %A Löwenberg, C., Julich-Gruner, K., Neffe, A., Lendlein, A. %D 2015 %J Advanced Functional Polymers for Medicine (AFPM) %T Influence of Ions on the Properties of Swollen Gelatin-Based Networks %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2015 %J The 5th International Conference on Bio-based Polymers (ICBP2015) %T Strategies for Implementing (Multi)functionality in Polymer-based Materials %U %X %0 conference lecture %@ %A Braune, S., Zhou, S., Groth, B., Lendlein, A., Jung, F. %D 2015 %J XLII Annual ESAO Conference %T Quantification of adherent platelets on polymer-based biomaterials. Comparison of colorimetric and microscopic assessment %U %X %0 conference lecture (invited) %@ %A Behl, M., Saatchi, M., Nöchel, U., Lendlein, A. %D 2015 %J Lecture at the Tianjin University %T Bidirectional shape-memory effect at human body temperature %U %X %0 journal article %@ 0935-9648 %A Neffe, A.T., Pierce, B.F., Tronci, G., Ma, N., Pittermann, E., Gebauer, T., Frank, O., Schossig, M., Xu, X., Willie, B.M., Forner, M., Ellinghaus, A., Lienau, J., Duda, G.N., Lendlein, A. %D 2015 %J Advanced Materials %N 10 %P 1738-1744 %R doi:10.1002/adma.201404787 %T One Step Creation of Multifunctional 3D Architectured Hydrogels Inducing Bone Regeneration %U https://doi.org/10.1002/adma.201404787 10 %X Structured hydrogels showing form stability and elastic properties individually tailorable on different length scales are accessible in a one-step process. They support cell adhesion and differentiation and display growing pore size during degradation. In vivo experiments demonstrate their efficacy in biomaterial-induced bone regeneration, not requiring addition of cells or growth factors. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2015 %J Lecture at University of Manchester; Centre for Tissue Injury & Repair %T Multifunctional Bio-based Polymers in Technology and Medicine %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2015 %J Hermann F. Mark Symposium 2015 %T Multifunctional bio-based Polymers in Technology and Medicine %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2015 %J World Conference on Regenerative Medicine 2015 %T Biofunctional Polymer-based Materials in Regenerative Medicine %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2015 %J 12th International Symposium on Stimuli-Responsive Materials %T Methods for Programming Stimuli-sensitivity in Polymer Networks %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2015 %J Informations- und Netzwerkveranstaltung der Deutschen Plattform NanoBioMedizin %T Translationale Biomaterialforschung %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2015 %J Exkursion einer Schülergruppe aus dem Weinberg-Gymnasium Kleinmachnow zur Berufsorientierung %T HZG in Teltow und Kunststoffe in der Medizin %U %X %0 conference lecture %@ %A Roch, T., Schroeter, M., Lendlein, A. %D 2015 %J Exkursion einer Schülergruppe aus dem Weinberg-Gymnasium Kleinmachnow zur Berufsorientierung %T Polymere als Biomaterialien %U %X %0 conference lecture %@ %A Vijaya Bhaskar, T., Roch, T., Ma, N., Lendlein, A. %D 2015 %J 34. Jahrestagung der Deutschen Gesellschaft für klinische Mikrozirkulation und Hämorheologie (DGKMH) %T The interaction of human macrophage subsets with silicone as a biomaterial %U %X %0 conference lecture %@ %A Wang, W., Kratz, K., Behl, M., Xu, X., Baudis, S., Li, Z., Kurtz, A., Ma, N., Lendlein, A. %D 2015 %J 34. Jahrestagung der Deutschen Gesellschaft für klinische Mikrozirkulation und Hämorheologie (DGKMH) %T The interaction of human adipose-derived mesenchymal stem cells and polyether ether ketone %U %X %0 conference poster %@ %A Roch, T., Kratz, K., Ma, N., Lendlein, A. %D 2015 %J 34. Jahrestagung der Deutschen Gesellschaft für klinische Mikrozirkulation und Hämorheologie (DGKMH) %T Polymeric inserts differing in their chemical composition as substrates for dendritic cell cultivation %U %X %0 conference poster %@ %A Tetali, S., Jankowski, V., Brettschneider, F., Lützow, K., Kratz, K., Lendlein, A., Jankowski, J. %D 2015 %J 34. Jahrestagung der Deutschen Gesellschaft für klinische Mikrozirkulation und Hämorheologie (DGKMH) %T Adsorption capacity of poly(etherimide) microparticles to uremic toxins %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2015 %J MRS Fall Meeting 2015; Symposium Y “Shape Programmable Materials” %T Programmable, Semi-crystalline Shape-memory Polymers %U %X %0 conference lecture %@ %A Neffe, A., Federico, S., Lendlein, A. %D 2015 %J MRS Fall Meeting 2015; Symposium H “Multifunctionality in Polymer-Based Materials; Gels and Interfaces” %T Crosslinking of Collagen Through Molecular Recognition by Biomimetic; Decorin-Derived Peptides %U %X %0 editorial %@ 1042-7147 %A Julich-Gruner, K.K., Pandit, A., Lendlein, A. %D 2015 %J Polymers for Advanced Technologies %N 12 %P 1357-1358 %R doi:10.1002/pat.3719 %T Editorial: Designing advanced functional polymers for medical applications %U https://doi.org/10.1002/pat.3719 12 %X No abstract %0 conference poster %@ %A Vuki evi , R., Neffe, A., Gebauer, T., Xu, X., Ma, N., Lendlein, A. %D 2015 %J MRS Fall Meeting 2015; Symposium H “Multifunctionality in Polymer-Based Materials; Gels and Interfaces” %T Mechanical Properties of Architectured Gelatin-Based Hydrogels on Different Hierarchical Levels %U %X %0 conference lecture %@ %A Lendlein, A., Schroeter, M. %D 2015 %J Tag der Wissenschaften 2015 am Weinberg-Gymnasium Kleinmachnow %T Wenn Kunststoffe auf ihre Umwelt reagieren - Chemische Stimuli und intelligente Kunststoffe %U %X %0 conference poster %@ %A Naolou, T., Brunacci, N., Neffe, A., Lendlein, A. %D 2015 %J MRS Fall Meeting 2015; Symposium H “Multifunctionality in Polymer-Based Materials; Gels and Interfaces” %T Oligodepsipeptide synthesis and formation of submicron particles thereof %U %X %0 conference lecture %@ %A Friess, F., Lendlein, A., Wischke, C. %D 2015 %J MRS Fall Meeting 2015; Symposium H “Multifunctionality in Polymer-Based Materials; Gels and Interfaces” %T Two-Phase Microfluidics with Inviscid Drops: Effects of Total Flow Rate and Delayed Surfactant Addition %U %X %0 journal article %@ 0168-3659 %A Wischke, C., Weigel, J., Bulavina, L., Lendlein, A. %D 2014 %J Journal of Controlled Release %P 86-91 %R doi:10.1016/j.jconrel.2014.07.047 %T Sustained release carrier for adenosine triphosphate as signaling molecule %U https://doi.org/10.1016/j.jconrel.2014.07.047 %X Adenosine triphosphate (ATP) is a molecule with a fascinating variety of intracellular and extracellular biological functions that go far beyond energy metabolism. Due to its limited passive diffusion through biological membranes, controlled release systems may allow to interact with ATP-mediated extracellular processes. In this study, two release systems were explored to evaluate the capacity for either long-term or short-term release: (i) Poly[(rac-lactide)-co-glycolide] (PLGA) implant rods were capable of ATP release over days to weeks, depending on the PLGA molecular weight and end-group capping, but were also associated with partial hydrolytic degradation of ATP to ADP and AMP, but not adenosine. (ii) Thermosensitive methylcellulose hydrogels with a gelation occurring at body temperature allowed combining adjustable loading levels and the capacity for injection, with injection forces less than 50 N even for small 27G needles. Finally, a first in vitro study illustrated purinergic-triggered response of primary murine microglia to ATP released from hydrogels, demonstrating the potential relevance for biomedical applications. %0 journal article %@ 1525-7797 %A Schoenwaelder, S.M.S., Bally, F., Heinke, L., Azucena, C., Bulut, Oe.D., Heissler, S., Kirschhoefer, F., Gebauer, T.P., Neffe, A.T., Lendlein, A., Brenner-Weiss, G., Lahann, J., Welle, A., Overhage, J., Woell, C. %D 2014 %J Biomacromolecules %N 7 %P 2398-2406 %R doi:10.1021/bm500750v %T Interaction of Human Plasma Proteins with Thin Gelatin-Based Hydrogel Films: A QCM-D and ToF-SIMS Study %U https://doi.org/10.1021/bm500750v 7 %X In the fields of surgery and regenerative medicine, it is crucial to understand the interactions of proteins with the biomaterials used as implants. Protein adsorption directly influences cell-material interactions in vivo and, as a result, regulates, for example, cell adhesion on the surface of the implant. Therefore, the development of suitable analytical techniques together with well-defined model systems allowing for the detection, characterization, and quantification of protein adsorbates is essential. In this study, a protocol for the deposition of highly stable, thin gelatin-based films on various substrates has been developed. The hydrogel films were characterized morphologically and chemically. Due to the obtained low thickness of the hydrogel layer, this setup allowed for a quantitative study on the interaction of human proteins (albumin and fibrinogen) with the hydrogel by Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D). This technique enables the determination of adsorbant mass and changes in the shear modulus of the hydrogel layer upon adsorption of human proteins. Furthermore, Secondary Ion Mass Spectrometry and principal component analysis was applied to monitor the changed composition of the topmost adsorbate layer. This approach opens interesting perspectives for a sensitive screening of viscoelastic biomaterials that could be used for regenerative medicine. %0 journal article %@ 0142-9612 %A Ullm, S., Krueger, A., Tondera, C., Gebauer, T.P., Neffe, A.T., Lendlein, A., Jung, F., Pietzsch, J. %D 2014 %J Biomaterials %N 37 %P 9755-9766 %R doi:10.1016/j.biomaterials.2014.08.023 %T Biocompatibility and inflammatory response in vitro and in vivo to gelatin-based biomaterials with tailorable elastic properties %U https://doi.org/10.1016/j.biomaterials.2014.08.023 37 %X Hydrogels prepared from gelatin and lysine diisocyanate ethyl ester provide tailorable elastic properties and degradation behavior. Their interaction with human aortic endothelial cells (HAEC) as well as human macrophages (Mɸ) and granulocytes (Gɸ) were explored. The experiments revealed a good biocompatibility, appropriate cell adhesion, and cell infiltration. Direct contact to hydrogels, but not contact to hydrolytic or enzymatic hydrogel degradation products, resulted in enhanced cyclooxygenase-2 (COX-2) expression in all cell types, indicating a weak inflammatory activation in vitro. Only Mɸ altered their cytokine secretion profile after direct hydrogel contact, indicating a comparably pronounced inflammatory activation. On the other hand, in HAEC the expression of tight junction proteins, as well as cytokine and matrix metalloproteinase secretion were not influenced by the hydrogels, suggesting a maintained endothelial cell function. This was in line with the finding that in HAEC increased thrombomodulin synthesis but no thrombomodulin membrane shedding occurred. First in vivo data obtained after subcutaneous implantation of the materials in immunocompetent mice revealed good integration of implants in the surrounding tissue, no progredient fibrous capsule formation, and no inflammatory tissue reaction in vivo. Overall, the study demonstrates the potential of gelatin-based hydrogels for temporal replacement and functional regeneration of damaged soft tissue. %0 journal article %@ 1386-0291 %A Wang, W., Xu, X., Li, Z., Lendlein, A., Ma, N. %D 2014 %J Clinical Hemorheology and Microcirculation %N 1 %P 19-48 %R doi:10.3233/CH-141883 %T Genetic engineering of mesenchymal stem cells by non-viral gene delivery %U https://doi.org/10.3233/CH-141883 1 %X Mesenchymal stem cells (MSCs) are an ideal cell source for tissue engineering and regenerative medicine as they possess self-renewal properties and multilineage differentiation potential. They can be isolated from various tissues and expanded easily through normal cell culture techniques. Genetic modifications of MSCs to further improve their therapeutic efficacy have been widely studied and extensively researched. Compared to viral gene delivery methods, non-viral methods generate less toxicity and immunogenicity and thus represent a promising and effective tool for the genetic engineering of MSCs. In the last decades, various non-viral gene delivery strategies have been developed and some of them have been applied for MSC transfection. This paper gives an overview of the techniques, influencing factors and potential applications of non-viral methods used for the genetic engineering of MSCs. %0 journal article %@ 0044-8249 %A Wei, Q., Becherer, T., Angioletti-Uberti, S., Dzubiella, J., Wischke, C., Neffe, A.T., Lendlein, A., Ballauff, M., Haag, R. %D 2014 %J Angewandte Chemie %N 31 %P 8138-8169 %R doi:10.1002/ange.201400546 %T Wechselwirkungen von Proteinen mit Polymerbeschichtungen und Biomaterialien %U https://doi.org/10.1002/ange.201400546 31 %X Die Proteinadsorption gilt als der wichtigste Faktor der Wechselwirkung zwischen polymeren Biomaterialien und Körperflüssigkeiten oder -gewebe. Die Haupteinflussfaktoren auf die Proteinadsorption sind wasservermittelte hydrophobe und Hydratationskräfte sowie elektrostatische Wechselwirkungen. Eine systematische Analyse verschiedener Monolagen führte zur Aufstellung allgemeiner Leitsätze, den sogenannten “Whitesides-Regeln”. Diese Konzepte wurden erfolgreich auf die Entwicklung verschiedener proteinresistenter Oberflächen angewendet und werden kontinuierlich weiterentwickelt, um das Verständnis von Protein-Material-Wechselwirkungen über die bisherigen Grenzen hinaus zu erweitern. Ebenso werden die Theorien zu Proteinadsorptionsmechanismen aufgrund der sich schnell entwickelnden analytischen Technologien fortlaufend verbessert. Ziel dieses Aufsatzes ist die Verbesserung der aufgestellten empirischen Leitlinien im Hinblick auf die theoretischen und analytischen Fortschritte. Dabei werden die aktuellen analytischen Methoden zur Untersuchung mechanistischer Hypothesen und Theorien zu Protein-Oberflächen-Wechselwirkungen besprochen. Ein besonderes Augenmerk liegt auf aktuellen Technologien im Bereich bioinerter und biospezifischer Beschichtungen und ihrer Anwendungen in der Biomedizin. %0 conference lecture %@ %A Wischke, C., Merino, M., Roch, T., Lendlein, A. %D 2014 %J HVI Workshop, Status Meeting at Makromolekulares Kolloquium 2014 %T Characterizing model particle surfaces with different cellular uptake behaviour %U %X %0 conference lecture %@ %A Wischke, C., Weigel, J., Bulavina, L., Lendlein, A. %D 2014 %J 13th European Symposium on Controlled Drug Delivery, ESCDD 2014 %T Sustained release carrier for adenosine triphosphate as signaling molecule %U %X %0 journal article %@ 0939-6411 %A Mathew, S., Lendlein, A., Wischke, C. %D 2014 %J European Journal of Pharmaceutics and Biopharmaceutics %N 2 %P 403-407 %R doi:10.1016/j.ejpb.2014.04.003 %T Characterization of protein-adjuvant coencapsulation in microparticles for vaccine delivery %U https://doi.org/10.1016/j.ejpb.2014.04.003 2 %X Protein antigens encapsulated as vaccines in poly[(rac-lactide)-co-glycolide] (PLGA) microparticle carriers can induce immune responses. The intensity and directions of this response can be controlled by coloading the microparticles with immunomodulatory adjuvants, e.g., muramyl dipeptide (MDP) as adjuvant combined with ovalbumin (Ova) as protein antigen. In this study, methodologies for an individual quantification of both encapsulated substances should be reported, which comprise (i) a separation process to isolate and determine MDP as intact molecule and (ii) a simultaneous degradation of both analytes with subsequent specific quantification of Ova fragments. It was shown that coloading of both substances resulted in a substantially reduced encapsulation efficiency of MDP. This illustrates that correct conclusions on dose–response relationships in future vaccination studies can only be drawn, if a selective method for adjuvant and protein quantification will be applied. %0 conference lecture (invited) %@ %A Braune, S., Jung, F., Lendlein, A. %D 2014 %J Focus on the Blood-Biomaterial Interface: Surface Analysis meets Blood Compatibility, 74th International IUVSTA Workshop %T Hemocompatibility testing of biomaterials - Approach for a standardized assessment of thrombogenic surfaces %U %X %0 journal article %@ 1386-0291 %A Braune, S., Walter, M., Schulze, F., Lendlein, A., Jung, F. %D 2014 %J Clinical Hemorheology and Microcirculation %N 1 %P 159-170 %R doi:10.3233/CH-141876 %T Changes in platelet morphology and function during 24 hours of storage %U https://doi.org/10.3233/CH-141876 1 %X For in vitro studies assessing the interaction of platelets with implant materials, common and standardized protocols for the preparation of platelet rich plasma (PRP) are lacking, which may lead to non-matching results due to the diversity of applied protocols. Particularly, the aging of platelets during prolonged preparation and storage times is discussed to lead to an underestimation of the material thrombogenicity. Here, we study the influence of whole blood- and PRP-storage times on changes in platelet morphology and function. Blood from apparently healthy subjects was collected according to a standardized protocol and examined immediately after blood collection, four hours and twenty four hours later. The capability of platelets to adhere and form stable aggregates (PFA100, closure time) was examined in sodium citrate anticoagulated whole blood (WB) using the agonists equine type I collagen and epinephrine bitartrate (collagen/epinephrine) as well as equine type I collagen and adenosine-5′-diphosphate (collagen/ADP). Circulating platelets were quantified at each time point. Morphology of platelets and platelet aggregates were visualized microscopically and measured using an electric field multi-channel counting system (CASY). The percentage of activated platelets was assessed by means of P-selectin (CD62P) expression of circulating platelets. Furthermore, platelet factor 4 (PF4) release was measured in platelet poor plasma (PPP) at each time point. Whole blood PFA100 closure times increased after stimulation with collagen/ADP and collagen/epinephrine. Twenty four hours after blood collection, both parameters were prolonged pathologically above the upper limit of the reference range. Numbers of circulating platelets, measured in PRP, decreased after four hours, but no longer after twenty four hours. Mean platelet volumes (MPV) and platelet large cell ratios (P-LCR, 12 fL – 40 fL) decreased over time. Immediately after blood collection, no debris or platelet aggregates could be visualized microscopically. After four hours, first debris and very small aggregates occurred. After 24 hours, platelet aggregates and also debris progressively increased. In accordance to this, the CASY system revealed an increase of platelet aggregates (up to 90 μm diameter) with increasing storage time. The percentage of CD62P positive platelets and PF4 increased significantly with storage time in resting PRP. When soluble ADP was added to stored PRP samples, the number of activatable platelets decreased significantly over storage time. The present study reveals the importance of a consequent standardization in the preparation of WB and PRP. Platelet morphology and function, particularly platelet reactivity to adherent or soluble agonists in their surrounding milieu, changed rapidly outside the vascular system. This knowledge is of crucial interest, particularly in the field of biomaterial development for cardiovascular applications, and may help to define common standards in the in vitro hemocompatibility testing of biomaterials. %0 conference object %@ 1932-6254 %A Arya, N., Gebauer, T.P., Neffe, A.T., Lendlein, A., Shastri, V.P. %D 2014 %J Journal of Tissue Engineering and Regenerative Medicine %N S1 %P 207-518 / PP 79 %R doi:10.1002/term.1932 %T Chondrocyte re-differentiation on ethyl lysine diisocyanate cross-linked gelatin based 3-D scaffolds: Application in cartilage tissue engineering %U https://doi.org/10.1002/term.1932 S1 %X No abstract %0 journal article %@ 1433-7851 %A Wei, Q., Becherer, T., Angioletti-Uberti, S., Dzubiella, J., Wischke, C., neffe, A.T., Lendlein, A., Ballauff, M., Haag, R. %D 2014 %J Angewandte Chemie - International Edition %N 31 %P 8004-8031 %R doi:10.1002/anie.201400546 %T Protein Interactions with Polymer Coatings and Biomaterials %U https://doi.org/10.1002/anie.201400546 31 %X Protein adsorption is considered to be the most important factor of the interaction between polymeric biomaterials and body fluids or tissues. Water-mediated hydrophobic and hydration forces as well as electrostatic interactions are believed to be the major factors of protein adsorption. A systematic analysis of various monolayer systems has resulted in general guidelines, the so-called “Whitesides rules”. These concepts have been successfully applied for designing various protein-resistant surfaces and are being studied to expand the understanding of protein–material interactions beyond existing limitations. Theories on the mechanisms of protein adsorption are constantly being improved due to the fast-developing analytical technologies. This Review is aimed at improving these empirical guidelines with regard to present theoretical and analytical advances. Current analytical methods to test mechanistic hypotheses and theories of protein–surface interactions will be discussed. Special focus will be given to state-of-the-art bioinert and biospecific coatings and their applications in biomedicine. %0 journal article %@ 2192-2659 %A Friess, F., Noechel, U., Lendlein, A., Wischke, C. %D 2014 %J Advanced Healthcare Materials %N 12 %P 1986-1990 %R doi:10.1002/adhm.201400433 %T Polymer Micronetworks with Shape-Memory as Future Platform to Explore Shape-Dependent Biological Effects %U https://doi.org/10.1002/adhm.201400433 12 %X Polymer micronetworks allowing stimuli-induced, predefined, and spatially directed shape shifts. The temperature-induced on-demand switching of shape is introduced as a function of polyester carriers. With their adjustable ­switching temperature, micronetworks may serve as a model system to explore static and dynamic shape effects in biological systems. %0 journal article %@ 1042-7147 %A Neffe, A.T., Chua, K., Luetzow, K., Pierce, B.F., Lendlein, A., Abell, A.D. %D 2014 %J Polymers for Advanced Technologies %N 11 %P 1371-1375 %R doi:10.1002/pat.3359 %T Crosslinking of gelatin by ring opening metathesis under aqueous conditions - An exploratory study %U https://doi.org/10.1002/pat.3359 11 %X Ring-opening metathesis catalysis has received little attention as a means to functionalize or crosslink biopolymers in water since the required catalysts are usually not stable under these conditions. However, biopolymer solubility suggests such a procedure. We show that Grubbs first and second generation catalysts (in emulsion) as well as a water-soluble Hoveyda-Grubbs catalyst can be applied to crosslink glycidyl methacrylated gelatin with norbornene dicarboxylic acid in water by a cross metathesis-ring opening metathesis approach. A mechanistic study suggests that cross metathesis between the functionalized polymer and the cyclic olefin acts as an initiating step for the crosslinking reaction. %0 journal article %@ 1042-7147 %A Karimi, M., Heuchel, M., Weigel, T., Kratz, K., Lendlein, A. %D 2014 %J Polymers for Advanced Technologies %N 11 %P 1349-1355 %R doi:10.1002/pat.3371 %T Influence of expansion cooling regime on morphology of poly(Epsilon-caprolactone) foams prepared by pressure quenching using supercritical CO2 %U https://doi.org/10.1002/pat.3371 11 %X Creation of foam structures from hydrolytically degradable poly(ε-caprolactone) (PCL) is a current task in biomaterial research. One example are degradable scaffolds. The thermodynamic and kinetic conditions in a supercritical CO2 (scCO2) supported foaming process of PCL can influence the resulting morphology of the foam. PCL foaming with scCO2 was systematically investigated in the pressure range from 78 to 200 bar at temperatures between 25°C and 50°C with the help of a view cell. PCL foams could be obtained at both conditions above the pressure dependent melting temperature as well as below this temperature, i.e. from supercooled melt states. Differential scanning calorimetry investigations of the PCL foam samples were used for the analysis of the relationship between pore morphology and foaming conditions. Three characteristic regions could be distinguished in the PCL/CO2 phase diagram. Only when the foaming was conducted above the critical temperature of CO2, a significant influence of the depressurization rate could be observed. Here, an increase in the quenching rate resulted in a decreasing pore size while the pore density was found to increase. %0 journal article %@ 1042-7147 %A Lendlein, A., Domb, A.J., Baudis, S., Behl, M. %D 2014 %J Polymers for Advanced Technologies %N 11 %P 1187-1188 %R doi:10.1002/pat.3377 %T From macromolecules to materials to systems %U https://doi.org/10.1002/pat.3377 11 %X No abstract %0 journal article %@ 1386-0291 %A Krueger, A., Mayer, A., Roch, T., Schulz, C., Lendlein, A. %D 2014 %J Clinical Hemorheology and Microcirculation %N 1 %P 229-240 %R doi:10.3233/CH-141875 %T Angiogenically stimulated alternative monocytes maintain their pro-angiogenic and non-inflammatory phenotype in long-term co-cultures with HUVEC %U https://doi.org/10.3233/CH-141875 1 %X Angiogenically stimulated alternative monocytes (aMO2) could be established as cellular release system accelerating the endothelialization of polymers rendering their surfaces hemocompatible in a short-term study. However, for their clinical application it is essential that aMO2 do not switch back to the MO1 state sustaining their capability as cellular release system over an extended period of time. We explored whether aMO2 can maintain their differentiation state over 21 days in a mono- and in a co-culture with HUVEC. In comparison, the influence of recombinant VEGF-A165 on the endothelialization of biomaterials was assessed including endothelial cell (HUVEC) density, organisation of the endothelial cytoskeleton, cytokine secretion profile and release of prostacyclin, thromboxaneA2 and matrix metalloproteinases. In mono-culture aMO2 secreted high amounts of VEGF and other growth factors/cytokines. Co-cultured with HUVEC, aMO2 accelerated the formation of a confluent HUVEC monolayer. Furthermore, no pro-inflammatory cytokines were found, neither in aMO2-mono, nor in co-cultures with HUVEC indicating that the majority of the aMO2 remained stable in their aMO2 state during the 21 days of cultivation. In contrast, the addition of recombinant VEGF-A165 instead of the co-culture with aMO2 resulted in the formation of stress fibres, dissociated marginal filament bands, and a detachment of HUVEC. In addition, the profile of bioactive agents of HUVEC (e.g. prostacyclin, thromboxaneA2, matrix metalloproteinases, IFN-γ and TNF-α) was influenced by the VEGF-A165 treatment inducing the detachment of HUVEC. In conclusion, in co-culture with HUVEC aMO2 remained stable in their type 2 state over 21 days confirming the suitability of aMO2 as biological release system for the endothelialization of biomaterial surfaces with constant release of angiogenic factors but without secretion of pro-inflammatory cytokines over three weeks. Therefore, this endothelialization approach seems to be appropriate to improve the hemocompatibility of cardiovascular implant materials in vitro, and proved to be superior to the use of recombinant VEGF-A165. %0 journal article %@ 2046-2069 %A Schmidt, C., Behl, M., Lendlein, A., Beuermann, S. %D 2014 %J RSC Advances %N 66 %P 35099-35105 %R doi:10.1039/c4ra06815g %T Synthesis of high molecular weight polyglycolide in supercritical carbon dioxide %U https://doi.org/10.1039/c4ra06815g 66 %X Polyglycolide (PGA) is a biodegradable polymer with multiple applications in the medical sector. Here the synthesis of high molecular weight polyglycolide by ring-opening polymerization of diglycolide is reported. For the first time stabilizer free supercritical carbon dioxide (scCO2) was used as a reaction medium. scCO2 allowed for a reduction in reaction temperature compared to conventional processes. Together with the lowering of monomer concentration and consequently reduced heat generation compared to bulk reactions thermal decomposition of the product occurring already during polymerization is strongly reduced. The reaction temperatures and pressures were varied between 120 and 150 °C and 145 to 1400 bar. Tin(II) ethyl hexanoate and 1-dodecanol were used as catalyst and initiator, respectively. The highest number average molecular weight of 31200 g mol−1 was obtained in 5 hours from polymerization at 120 °C and 530 bar. In all cases the products were obtained as a dry white powder. Remarkably, independent of molecular weight the melting temperatures were always at (219 ± 2) °C. %0 journal article %@ 1042-7147 %A Friess, F., Lendlein, A., Wischke, C. %D 2014 %J Polymers for Advanced Technologies %N 11 %P 1285-1292 %R doi:10.1002/pat.3313 %T Photoinduced synthesis of polyester networks from methacrylate functionalized precursors: analysis of side reactions %U https://doi.org/10.1002/pat.3313 11 %X Polyester networks can be prepared by ultraviolet (UV)-light-induced radical polymerization of methacrylate functionalized oligo(ε-caprolactone)s. The properties and functions of the obtained materials depend on defined network structures and may be altered, if crosslinking would occur by side reactions in other positions than the methacrylate endgroups. In order to explore whether and to which extent such side reactions occur, network synthesis as well as related model reactions were performed in the absence of photoinitiator. Hereby precursor structures (linear and four-arm star-shaped) and reaction conditions (in solution and in the melt) were varied. Unspecific side reactions were found only upon extensive UV irradiation for 60 min (26 mW cm-2) with minor but detectable alterations of physicochemical properties of the networks. The analysis of model reactions suggested minor photolytic cleavage of ester bonds during polymer network synthesis. However, the effect of these side reactions on network properties and functions appeared to be less relevant than an incomplete precursor integration because of a too short UV irradiation for crosslinking. %0 journal article %@ 0032-3861 %A Razzaq, M.Y., Behl, M., Noechel, U., Lendlein, A. %D 2014 %J Polymer %N 23 %P 5953-5960 %R doi:10.1016/j.polymer.2014.07.025 %T Magnetically controlled shape-memory effects of hybrid nanocomposites from oligo(Omega-pentadecalactone) and covalently integrated magnetite nanoparticles %U https://doi.org/10.1016/j.polymer.2014.07.025 23 %X The covalent integration of inorganic nanoparticles in polymer matrices has gained significance for improving the structural properties of polymer-based materials. Here we report on the performance of poly(ω-pentadecalactone) networks with magnetite nanoparticles as netpoints in their magnetically-controlled shape-memory capability. Hybrid nanocomposites with magnetite nanoparticle content ranging from 5 to 11 wt% were prepared by reacting two types of oligo(ω-pentadecalactone) (OPDL) based precursors with terminal hydroxy groups, a three arm OPDL (3AOPDL, Mn = 6000 g mol−1) and an OPDL (Mn = 3300 g mol−1) coated magnetite nanoparticle (∅ = 10 nm), with a diisocyanate. Homogenous hybrid nanocomposites were obtained independent from the weight content of the OPDL decorated nanoparticles in the samples. At 100 °C (T > Tm-OPDL) the covalent integration of the nanoparticles increased the mechanical strength with increasing weight content whereby the elasticity remained almost constant. In magnetically-controlled one-way dual-shape experiments the shape fixity decreased from 95% to 90% but the shape recovery increased slightly from 95% to 97% when the nanoparticle content was increased. In magnetically-controlled reversible dual-shape experiments the nanoparticles had a restraining effect and the maximum shape-change of 65% for hybrid nanocomposites with 5 wt% magnetite nanoparticles was reduced to 36% when the particle content was increased to 11 wt%. These results show that the performance of hybrid nanocomposites can be tailored by nanoparticle content, however in terms of their applicability either mechanical strength or actuation capability should be focussed in the material selection. %0 conference lecture %@ %A Braune, S., Gross, M., Walter, M., Zhou, S., Dietze, S., Kratz, K., Lendlein, A., Tschoepe, C., Jung, F. %D 2014 %J 33. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Platelet adhesion and activation on polymer-based biomaterials - A comparative pilot study of platelets from patients with coronary artery disease and apparently healthy donors %U %X %0 conference lecture %@ %A Julich-Gruner, K.K., Lendlein, A., Boccaccini, A.R., Neffe, A.T. %D 2014 %J 2014 MRS Fall Meeting & Exhibit %T Anisotropic Composites of Desaminotyrosine and Desaminotyrosyl Tyrosine Functionalized Gelatin and Bioactive Glass Microparticles %U %X %0 conference lecture %@ %A Wischke, C., Mathew, S., Roch, T., Krueger, A., Lendlein, A. %D 2014 %J BioBarriers 2014 %T Active Particulate Polymer Carriers %U %X %0 journal article %@ 2050-750X %A Neffe, A.T., Ruesten-Lange, M.v., Braune, S., Luetzow, K., Roch, T., Richau, K., Krueger, A., Becherer, T., Thuenemann, A.F., Jung, F., Haag, R., Lendlein, A. %D 2014 %J Journal of Materials Chemistry B %N 23 %P 3626-3635 %R doi:10.1039/C4TB00184B %T Multivalent grafting of hyperbranched oligo- and polyglycerols shielding rough membranes to mediate hemocompatibility %U https://doi.org/10.1039/C4TB00184B 23 %X Hemocompatible materials are needed for internal and extracorporeal biomedical applications, which should be realizable by reducing protein and thrombocyte adhesion to such materials. Polyethers have been demonstrated to be highly efficient in this respect on smooth surfaces. Here, we investigate the grafting of oligo- and polyglycerols to rough poly(ether imide) membranes as a polymer relevant to biomedical applications and show the reduction of protein and thrombocyte adhesion as well as thrombocyte activation. It could be demonstrated that, by performing surface grafting with oligo- and polyglycerols of relatively high polydispersity (>1.5) and several reactive groups for surface anchoring, full surface shielding can be reached, which leads to reduced protein adsorption of albumin and fibrinogen. In addition, adherent thrombocytes were not activated. This could be clearly shown by immunostaining adherent proteins and analyzing the thrombocyte covered area. The presented work provides an important strategy for the development of application relevant hemocompatible 3D structured materials. %0 conference poster %@ %A Neffe, A.T., Ruesten-Lange, M.v., Braune, S., Luetzow, K., Roch, T., Jung, F., Weinhart, M., Haag, R., Lendlein, A. %D 2014 %J Makromolekulares Kolloquium 2014 %T Polyethers on Porous Polymer Surfaces: Relevant Models to Study Protein Adsorption and Hemocompatibility %U %X %0 journal article %@ 1386-0291 %A Roch, T., Schulz, C., Jung, F., Ma, N., Lendlein, A. %D 2014 %J Clinical Hemorheology and Microcirculation %N 2 %P 203-212 %R doi:10.3233/CH-141831 %T Interaction of poly(ether imide) films with early immune mechanisms %U https://doi.org/10.3233/CH-141831 2 %X With the worldwide increase of atherosclerosis, the need for new engineered patient specific implants such as stents or vascular grafts is still emerging. Recently, very smooth poly(ether imide) (PEI) films were, based on their excellent hemocompatibility and compatibility with endothelial cells, suggested as potential biomaterial for cardiovascular applications. In atherosclerosis, immune mechanisms such as complement activation, but also cellular responses such as monocytes and neutrophils activation, can mediate the inflammatory response. Therefore, it is important that the implant material itself does not trigger the inflammatory response. Early immune mechanisms - e.g. macrophage activation, complement induction, generation of reactive oxygen species (ROS), and the secretion of inflammatory cytokines by leukocytes - could potentiate the inflammatory responses, and may thereby alter endothelial cells behaviour or facilitate platelet activation. Therefore, it is important to evaluate the immuno-compatibility of PEI-films. The PEI-films were fabricated from commercially available PEI, which was dissolved in dichloromethane and pulled out on a cleaned, smooth glass surface and subsequently, solvent residues were removed during the drying procedure. Using a murine macrophage reporter cell line possible material bound microbial contaminations and material intrinsic immuno-stimulatory properties were investigated. The macrophages were viable after adhering on the PEI-films and did not show signs of activation, indicating that the used PEI-film was free of microbial contaminations. To determine whether PEI-films induced complement activation, the release of C5a in pooled human plasma was analyzed. The detected C5a levels did not differ between PEI-films and tissue culture plates (TCP), which served as control material. Furthermore, in whole human blood, the generation of ROS as well as the cytokine production were investigated by flow cytometry and by multiplex bead arrays, respectively. The production of IL-6 and TNF-α as well as the generation of ROS by immune cells of the whole blood was not induced upon contact with PEI-films. The immunological evaluation of PEI-films revealed that no substantial activation of the investigated early immune mechanisms occurred. Altogether, this data demonstrate that PEI is immuno-compatible and from that perspective may be a suitable biomaterial for cardiovascular applications. %0 journal article %@ 1386-0291 %A Schulz, C., Ruesten-Lange, M.v., Krueger, A., Lendlein, A., Jung, F. %D 2014 %J Clinical Hemorheology and Microcirculation %N 2 %P 147-158 %R doi:10.3233/CH-141826 %T Adherence and shear-resistance of primary human endothelial cells on smooth poly(ether imide) films %U https://doi.org/10.3233/CH-141826 2 %X BACKGROUND: Occlusions of artificial small-diameter cardiovascular grafts are frequent events after implantation, often caused by clot formations. A main factor is the insufficient hemocompatibility of the inner artificial graft surface, which could be improved by endothelialization. Therefore, one challenge in cardiovascular graft engineering is the establishment of a shear-resistant endothelial cell layer to prevent cell detachment by shear forces after implantation. MATERIALS AND METHODS: Recently, very smooth (Rq = 2.37 ± 1.40 nm) poly(ether imide) (PEI) films were introduced as a biocompatible candidate material for cardiovascular devices. In this study the stability of primary human umbilical vein endothelial cell (HUVEC) monolayer was investigated after long-term seeding (9 days) on PEI-films and subsequent exposure to a venous shear stress of 3 dyn/cm2 for up to 6 hours using the cone-and-plate shearing technique. Cell density, growth pattern and morphology of HUVEC were determined prior and after shearing compared to glass as control substrate. HUVEC adhering to the substrate after shear stress were counted and analyzed by fluorescent staining. Supernatants were collected and secretion profile analysis of vasoactive and inflammatory mediators was performed. RESULTS: The cell density on PEI-films compared to the controls was slightly higher after long-term seeding and exposure to shear stress (glass: 71,656 ± 8,830 cells/cm2 and 42,239 ± 5,607 cells/cm2; PEI-film: 64,056 ± 2,829 cells/cm2 and 45,422 ± 2,507 cells/cm2 before and after shear stress, respectively). Actin- and vinculin-staining revealed a scattered re-organization of the cytoskeleton as well as a formation of stress fibers and focal adhesion points. Secretion of prostacyclin and thromboxane A2 was increased after application of shear stress, but no significant differences were detectable between cells growing on PEI-films or glass. Amounts of secreted inflammatory cytokines IL-6 and IL-8 in the supernatant were significantly lower for HUVEC seeded on PEI-films compared to glass before as well as after stress. CONCLUSION: The study demonstrated that HUVEC were able to resist exposure to venous shear stress when seeded on smooth PEI-films with typical morphology and adhesion behavior. However, HUVEC adherence on PEI was not yet sufficient to retain a complete cell monolayer after shear stress exposure. Occasionally, single cells or cell plaques were disrupted resulting in cell free areas in the confluent HUVEC layer. Apart from this our data suggest that PEI is a suitable substrate for HUVEC under static and dynamic conditions and therefore a promising candidate material for cardiovascular applications. The next objective is a surface functionalization of the PEI-films in a cell specific manner to reach a functionally confluent, shear resistant HUVEC monolayer. %0 book part %@ %A Neffe, A., Julich-Gruner, K., Lendlein, A. %D 2014 %J Biomaterials for Bone Regeneration: Novel Techniques and Applications %P 87-109 %T Combinations of biopolymers and synthetic polymers for bone regeneration %U %X Critical bone defects do not heal by themselves, but the regeneration process can be supported by biomaterial implants. Combinations of synthetic polymers, intended to provide the required mechanical strength and processability, and biopolymers, giving cells a suitable environment for proliferation and inducing bone growth, has recently drawn attention in order to provide multifunctional implants. In this chapter, the combination of the different polymer classes on the molecular level and by surface functionalization is discussed, with an emphasis on physicochemical properties and the biological functions of the materials as well as future trends in this research field. %0 conference lecture (invited) %@ %A Wischke, C., Lendlein, A. %D 2014 %J 12. Bionnale 2014 %T Multifunktionale Biomaterialien %U %X %0 journal article %@ 1022-1352 %A Lv, J., Hao, X., Yang, J., Feng, Y., Behl, M., Lendlein, A. %D 2014 %J Macromolecular Chemistry and Physics %N 24 %P 2463-2472 %R doi:10.1002/macp.201400345 %T Self-Assembly of Polyethylenimine-Modified Biodegradable Complex Micelles as Gene Transfer Vector for Proliferation of Endothelial Cells %U https://doi.org/10.1002/macp.201400345 24 %X Polyethylenimine (PEI) can perfectly condense with DNA and sufficiently transfer genes, but its high toxicity limits its application. Here, complex micelles are prepared as low-toxicity gene vectors by self-assembly of two block copolymers in aqueous solution. The complex micelles consist of a biodegradable poly(lactide-co-glycolide) (PLGA) core and a mixed poly(ethylene glycol) (PEG)/PEI shell. The ZNF580 gene plasmid (pEGFP-ZNF580), which has the ability of enhancing the proliferation of vascular endothelial cells, is encapsulated into the complex micelles. Using dynamic light scattering, the degradation behavior of the micelles is investigated in vitro. The hydrodynamic size and zeta potential of blank and DNA-loaded micelles are feasible to cellular uptake and gene transfection. 3-(4,5-Dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay shows that the cytotoxicity of the complex micelles is very low when the PEG/PEI ratio is 3/1. The DNA-loaded micelles are found to be able to enhance the proliferation of endothelial cells. %0 journal article %@ 0743-7463 %A Wischke, C., Lendlein, A. %D 2014 %J Langmuir %N 10 %P 2820-2827 %R doi:10.1021/la4025926 %T Method for Preparation, Programming, and Characterization of Miniaturized Particulate Shape-Memory Polymer Matrices %U https://doi.org/10.1021/la4025926 10 %X Their capability to change their shape on demand has created significant interest for shape-memory polymers (SMPs) in minimally invasive surgery. To evaluate the miniaturization of SMP matrices for small-sized implants or controlled release systems, a strategy to prepare and evaluate microsized SMP model particles is required. This methodological study reports the emulsion-based preparation of ∼30 μm microparticles (MPs) from a phase-segregated SMP, poly(ε-caprolactone) [PCL] and poly(ω-pentadecalactone) [PPDL], with a particular focus on the effects of process parameters such as polymer solvents or stabilizer type/concentration on formation and size distribution of SMP MPs. Processes for the preparation of SMP MP-loaded water-soluble polymer films with tailored mechanical properties were developed and applied for programming the SMP MP to a temporary ellipsoid shape by film stretching. For the functional evaluation of shape recovery of MPs, a light microscopy-based setup with temperature control is proposed by which the stimuli-induced switching of the microsized SMP matrices could be confirmed. Overall, by applying this methodological strategy to various thermoplastic SMPs, a routine to identify and characterize the microscale functionality of SMPs in miniaturized applications will be broadly accessible. %0 conference poster %@ %A Zhou, S., Braune, S., Groth, B., Lendlein, A., Jung, F. %D 2014 %J 33. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Quantification of adherent platelet densities on different substrates by lactate dehydrogenase and acid phosphatase assays in comparison to an image-based analysis %U %X %0 journal article %@ 2192-2659 %A Xu, X., Wang, W., Kratz, K., Fang, L., Li, Z., Kurtz, A., Ma, N., Lendlein, A. %D 2014 %J Advanced Healthcare Materials %N 12 %P 1991-2003 %R doi:10.1002/adhm.201400415 %T Controlling Major Cellular Processes of Human Mesenchymal Stem Cells using Microwell Structures %U https://doi.org/10.1002/adhm.201400415 12 %X Directing stem cells towards a desired location and function by utilizing the structural cues of biomaterials is a promising approach for inducing effective tissue regeneration. Here, the cellular response of human adipose-derived mesenchymal stem cells (hADSCs) to structural signals from microstructured substrates comprising arrays of square-shaped or round-shaped microwells is explored as a transitional model between 2D and 3D systems. Microwells with a side length/diameter of 50 μm show advantages over 10 μm and 25 μm microwells for accommodating hADSCs within single microwells rather than in the inter-microwell area. The cell morphologies are three-dimensionally modulated by the microwell structure due to differences in focal adhesion and consequent alterations of the cytoskeleton. In contrast to the substrate with 50 μm round-shaped microwells, the substrate with 50 μm square-shaped microwells promotes the proliferation and osteogenic differentiation potential of hADSCs but reduces the cell migration velocity and distance. Such microwell shape-dependent modulatory effects are highly associated with Rho/ROCK signaling. Following ROCK inhibition, the differences in migration, proliferation, and osteogenesis between cells on different substrates are diminished. These results highlight the possibility to control stem cell functions through the use of structured microwells combined with the manipulation of Rho/ROCK signaling. %0 journal article %@ 1022-1360 %A Neffe, A.T., Santan, H.D., Kamlage, S., Gottschalk, B., Lendlein, A. %D 2014 %J Macromolecular Symposia %N 1 %P 91-97 %R doi:10.1002/masy.201400145 %T Micellization of Aminoterminated Poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) in the Presence of Hyaluronic Acid %U https://doi.org/10.1002/masy.201400145 1 %X At concentrations above 15 wt-%, aqueous solutions of mixtures of aminoterminated poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) block copolymers (PEPE) and hyaluronic acid show a reversible sol-gel-transition upon change of temperature. For non-aminoterminated PEPEs, this gel transition could be related to micellization and subsequent colloidal jamming of the micelles. Here, the mechanism of gelation for the aminoterminated compound is investigated by fluorescence spectroscopy and 1H-NMR spectroscopy. The aminoterminated PEPE also form micelles. The onset of micellization is temperature and concentration dependent, and can be tuned to 20–40 °C. Interestingly, with increasing molecular weight of the hyaluronic acid component, the micellization is observed at lower concentrations. %0 conference lecture %@ %A Krueger, A., Ullm, S., Gebauer, T.G., Neffe, A.T., Pietzsch, J., Jung, F., Lendlein, A. %D 2014 %J 33. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Interaction between human umbilical venous endothelial cell and a gelatin-based hydrogel %U %X %0 journal article %@ 1022-1360 %A Baudis, S., Lendlein, A., Behl, M. %D 2014 %J Macromolecular Symposia %N 1 %P 105-111 %R doi:10.1002/masy.201400159 %T High-Throughput Synthesis as a Technology Platform for Copolymer Libraries %U https://doi.org/10.1002/masy.201400159 1 %X Quantitative structure-property relationships are of utmost importance for the rational design of materials. A systematic variation of one structure parameter in a series of polymers requires a large number of syntheses. Here combinatorial techniques are the method of choice. In this study high-throughput methods were applied for the synthesis and characterization of polymer libraries with stepwise changed composition to build up such material libraries. A high-throughput workflow was established, in which 112 different copolymerizations were performed. The polymers were characterized by means of NMR and FTIR (composition), GPC (number average molecular weight, inline imageand DSC (glass transition temperature, Tg). The gradually changed composition of the copolymers with number average molecular weights of around 150 kg ∙ mol-1 was confirmed and structure-property relationships between composition and Tgs ranging between 102 and 126 °C were proposed, rendering the polymer libraries now as a technology platform for further studies. %0 journal article %@ 1022-1360 %A Saatchi, M., Behl, M., Lendlein, A. %D 2014 %J Macromolecular Symposia %N 1 %P 100-107 %R doi:10.1002/masy.201400158 %T Double Layer Porous Structures by an Injection Molding/Particulate Leaching Approach %U https://doi.org/10.1002/masy.201400158 1 %X Scaffolds as a temporary substitute for the extracellular matrix should provide interconnected pores and often require a multilayer design to mimic the geometry and biomechanics of the target tissue. Here, it was explored whether bilayer porous structures can be obtained by a process free of organic solvents and how the individual layers contribute to the overall elastic properties. Porous layers were obtained from polyurethane (PU) blends with polyvinyl alcohol (PVA), which were immersed in water after sequential injection molding. Pore sizes in both layers ranged from 1 μm to 100 μm with an average of 22 ± 1 μm at a porosity of 50 ± 5% in combination with a high interconnectivity. The pore sizes were tailored by applying an annealing treatment, while the porosity was kept constant. Mechanical properties of the individual layers and the double layer constructs as determined by tensile tests suggested that the overall elasticity of the compact bilayer construct and porous bilayer construct was in agreement with the predicted overall elasticity according to the rule of mixtures. The porous bilayer model system will serve as a basis for determining structure-property relationships with respect to pore size, porosity as well as mechanical properties of individual layers and in this way enable a knowledge-based design of layered scaffolds. %0 journal article %@ 1022-1360 %A Balk, M., Behl, M., Noechel, U., Lendlein, A. %D 2014 %J Macromolecular Symposia %N 1 %P 8-13 %R doi:10.1002/masy.201400043 %T Shape-Memory Hydrogels with Crystallizable Oligotetrahydrofuran Side Chains %U https://doi.org/10.1002/masy.201400043 1 %X Stimuli-sensitive materials, such as shape-memory polymers (SMP) have attracted tremendous interest in the field of biomedical applications and Regenerative Therapies. In case of implants intended for soft tissue, adequate elastic properties can be mimicked by water swollen hydrophilic polymer networks (i.e. hydrogels) and can be equipped with a shape-memory capability. Shape-memory hydrogels (SMHs) having body compatible transition temperatures (Ttrans) have not been reported so far. Here we explored, whether SMHs with Ttrans ≤ 37 °C could be created consisting of the hydrophilic poly(N-vinyl pyrrolidone) segment, the crosslinker oligo(ethylene glycol) dimethacrylate (OEGDMA, Mn = 370 g · mol−1), and grafted crystallizable oligotetrahydrofuran (OTHF, Mn = 7.100 g · mol−1, Tm = 31 °C) segments as switching domains. As function of the OTHF content (30–75 wt%), the hydrogels had a degree of swelling between 450 and 3200%, a Ttrans about 26 °C, and soft mechanical properties in the kPa range. Therefore, these SMHs might be interesting biomaterial candidates e.g. as smart implants. %0 journal article %@ 1022-1360 %A Jiang, Y., Fang, L., Kratz, K., Lendlein, A. %D 2014 %J Macromolecular Symposia %N 1 %P 59-65 %R doi:10.1002/masy.201400138 %T Crystallization Behavior of Copolyesterurethanes Containing Different Weight Contents of Crystallizable Poly(Epsilon-caprolactone) Segments %U https://doi.org/10.1002/masy.201400138 1 %X Multiblock copolymers composed of crystallizable poly(ω-pentadecalactone) (PPDL) and poly(ε-caprolactone) (PCL) segments, which are linked via an aliphatic urethane unit, named PDLCL, have been recently introduced as temperature-memory materials. In this work, we studied the effect of different PCL weight content on the crystallization behavior of both PCL and PPDL domains in PDLCLs by differential scanning calorimetry (DSC), optical microscopy (OM) and atomic force microscopy (AFM). The results demonstrated that the nucleation mechanism of PCL crystals, the crystallization and melting temperatures of PCL domains, as well as their crystal morphology and size were found to change with varying composition, i.e., PCL weight content. %0 journal article %@ 1022-1360 %A Wang, L., Noechel, U., Fang, L., Kratz, K., Lendlein, A. %D 2014 %J Macromolecular Symposia %N 1 %P 82-90 %R doi:10.1002/masy.201400141 %T Impact of Molecular Architectures on the Thermal and Mechanical Properties of Multi-Phase Polymer Networks %U https://doi.org/10.1002/masy.201400141 1 %X Multiphase copolymer networks (CLEG) composed of crystallizable poly(ε-caprolactone) (PCL) and crystallizable poly(ethylene glycol) (PEG) segments can exhibit a pronounced triple-shape effect in the dry state or a dual-shape effect in the water swollen, hydrogel state. We hypothesize that by adjusting the network architecture of CLEG copolymers networks the swelling behavior, the thermal and mechanical properties, as well as the crystal structure of PEG and PCL domains can be tailored. Here, we studied CLEG materials with a fixed PCL/PEG weight ratio but different polymer network architectures, whereby the PEG segments were incorporated as grafted side chains or as network chains connecting two netpoints. The prepared CLEGs were analyzed regarding their gel contents, swelling behavior, thermal and mechanical properties and finally the crystallinity of the polymer networks were determined by differential scanning calorimetry (DSC) and wide angle X-ray scattering (WAXS) measurements. High gel content values of G  ≥ 98% were achieved for all copolymer network samples, indicating an almost complete conversion of the reaction precursors. The degree of swelling (Q) determined with water increased from Q ≈ 150% to 223% with increasing poly(ethylene glycol) monomethyl monomethacrylate (PEGMMA) content to create more PEG grafted side chains. Only when PEGMMA moieties were present in the CLEG networks two separated melting transitions related to the PCL and PEG segments were obtained, whereby Tm,PEG was found to increase with increasing the PEGMMA weight fraction. Based on this observation it can be assumed that the incorporated poly(ε-caprolactone) diisocyanoethyl methacrylate PEGDIMA segments forming the main network were not able to form crystallites in CLEG networks. An almost two-fold decrease in the Younǵs modulus was observed with increasing amounts of grafted PEG side chains, while the elongation at break increased significantly. Based on Mooney-Rivlin Equations, the crosslinking density increased from 0.10% to 0.21% when PEG segments switched from grafted chains to the network. WAXS and DSC investigations revealed an increase in the degree of crystallinity (DOC) of PEG segments with increasing PEGMMA moieties, while the DOC related to the crystalline PCL domains remained almost constant. The obtained results clearly demonstrated the importance of the molecular architecture in designing polymer networks. %0 journal article %@ 1386-0291 %A Roch, T., Akymenko, O., Krueger, A., Jung, F., Ma, N., Lendlein, A. %D 2014 %J Clinical Hemorheology and Microcirculation %N 1 %P 147-158 %R doi:10.3233/CH-141885 %T Expression pattern analysis and activity determination of matrix metalloproteinase derived from human macrophage subsets %U https://doi.org/10.3233/CH-141885 1 %X The polarization behavior of macrophages determines the clinical outcome after implantation of biomaterials. Formation of classically activated macrophages (CAM) may result in cell fusion to form foreign body giant cells, which induce and support uncontrolled inflammatory responses and can cause undesired material degradation. In contrast, polarization into alternatively activated macrophages (AAM) is assumed to support healing processes and implant integration. The expression of matrix metalloproteinases (MMP) by the different macrophage subsets might play a crucial role for inflammatory and wound healing processes and may subsequently influence the implant integration. Therefore, it is of importance to characterize the MMP expression pattern by the different macrophage subsets. This knowledge could support the design of biomaterials in which specific MMP cleavage sites are incorporated allowing a controlled cell-mediated degradation of the material. However, it needs to be considered that the pure expression levels may not correlate with the enzymatic activity of the MMP, which depends on a variety of different parameters such as additional co-factors. For this reason, the differential MMP expression levels and the overall enzymatic activity of in vitro generated human non-polarized macrophages (M0), CAM, and AAM are analyzed in this study. While MMP-1, MMP-3, and MMP-10 showed the highest expression levels in CAM, MMP-12 was most strongly expressed by AAM. Interestingly, although various MMP were expressed at high levels in CAM, the enzymatic MMP activity was increased in supernatants of AAM cultures. The data presented here illustrate the importance to combine the measurement of MMP expression levels with the analysis of the enzymatic activity. The observed MMP-12 expression in combination with the higher enzymatic activity detected in AAM supernatants might motivate the design of biomaterials, whose structure could be modified by MMP-12 catalyzed reactions leading to interactive polymers. %0 conference lecture %@ %A Roch, T., Akymenko, O., Krueger, A., Jung, F., Ma, N., Lendlein, A. %D 2014 %J 33. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Expression pattern analysis and activity determination of matrix metalloproteinase derived from human macrophage subsets %U %X %0 conference lecture %@ %A Krueger, A., Dietze, S., Kratz, K., Jung, F., Lendlein, A. %D 2014 %J 33. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Endothelial cell migration on different polymer-based biomaterials %U %X %0 journal article %@ 2192-2659 %A Xu, X., Wang, W., Kratz, K., Fang, L., Li, Z., Kurtz, A., Ma, N., Lendlein, A. %D 2014 %J Advanced Healthcare Materials %N 12 %P 1933 %R doi:10.1002/adhm.201470060 %T Cover Picture - Stem Cells: Controlling Major Cellular Processes of Human Mesenchymal Stem Cells using Microwell Structures %U https://doi.org/10.1002/adhm.201470060 12 %X The geometry of polymeric matrices is a powerful tool to control cell behavior. On page 1991 N. Ma, A. Lendlein, and co-workers demonstrate human adipose-derived stem cells that show ROCK pathway-mediated differences in their response to square- and round-shaped microwells with respect to their morphology, proliferation, migration, and differentiation. Phagocytes react differently to spherical and ellipsoid microparticles, which now can shift their shape upon stimulation due to an internal polymer micronetwork structure. %0 journal article %@ 1022-1360 %A Fang, L., Yan, W., Zierke, M., Richau, K., Behl, M., Kratz, K., Lendlein, A. %D 2014 %J Macromolecular Symposia %N 1 %P 83-90 %R doi:10.1002/masy.201400143 %T Crystallization and Phase Segregation of Multifunctional Multiblock Copolymers in Spin Coated Thin Films Altered by Diurethane Junction Units %U https://doi.org/10.1002/masy.201400143 1 %X A multiblock copolymer named PDC is composed of crystallizable oligo(p-dioxanone) (OPDO) and oligo(ε-caprolactone) (OCL) as hard and switching segments. PDC has been synthesized via connecting two oligomeric macrodiols using a diisocyanate linker such as 2,2(4), 4-trimethyl-hexamethylene diisocyanate (TMDI) or 1,6-hexamethylene diisocyanate (HDI). In this work, the surface morphologies of spin coated thin films from two PDCs (PDC-HDI and PDC-TMDI) were investigated via in-situ atomic force microscopy (AFM) to examine how the diisocyanate linkers affect the balance between crystallization and phase segregation behavior. The results demonstrated that in PDC-HDI, the crystallization of poly(ε-caprolactone) (PCL) crystals provoked a “break out” from the phase segregated morphology. On contrary, the crystallization of PCL crystals in PDC-TMDI was strictly confined in the phase segregated morphology. %0 conference poster %@ %A Stoermann, F., Wischke, C., Lendlein, A. %D 2014 %J 2014 MRS Fall Meeting & Exhibit %T Photo-Reversibility of Cinnamylidene Acetic Acid Derived Crosslinks in Poly(Epsilon-caprolactone) Networks %U %X %0 conference lecture %@ %A Walter, M., Braune, S., Schulze, F., Lendlein, A., Jung, F. %D 2014 %J 33. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Platelet morphology and function during storage up to 24 hours %U %X %0 conference poster %@ %A Wischke, C., Merino, M., Roch, T., Krueger, A., Lendlein, A. %D 2014 %J Makromolekulares Kolloquium 2014 %T Copolymer nanoparticles: effects of polymer composition and inflammatory conditions on endocytosis by endothelial cells %U %X %0 journal article %@ 1022-1360 %A Kusmierczuk, M., Noechel, U., Baudis, S., Behl, M., Kratz, K., Lendlein, A. %D 2014 %J Macromolecular Symposia %N 1 %P 98-104 %R doi:10.1002/masy.201400150 %T Shape-Memory Polymer Networks Prepared from Star-Shaped Poly[(L-lactide)-co-glycolide] Precursors %U https://doi.org/10.1002/masy.201400150 1 %X Amorphous degradable copolymer networks such as poly[(L-lactide)-co-glycolide] (PLGA) are promising multifunctional polymers with tailorable degradation profiles and capable of a thermally-induced shape-memory effect. Currently, the shape-memory performance for covalently crosslinked networks based on linear PLGA dimethacrylate precursors (cPLGA) is limited. In this study we explored the shape-memory properties of cPLGA networks prepared from three-armed 2-isocyanatoethyl methacrylate functionalized precursors via photopolymerization. cPLGA exhibited excellent dual-shape properties characterized by an almost complete fixation of the temporary shape as well as an almost perfect recovery of the original shape. In the dry state cPLGA exhibited a switching temperature (Tsw) of 60 °C with a narrow recovery temperature interval of ΔTrec = 5 °C, while a significant lower Tsw of 40 °C with a ΔTrec = 15 °C was obtained when the polymer network was investigated in an aqueous environment. A concomitant decrease in the glass transition temperature could be observed in differential scanning calorimetry heating curves for copolymer networks after storage in aqueous buffer solution at 37 °C for 7 days, which can be attributed to the up-take of water molecules (1.5 wt%). The shape-memory properties achieved for cPLGA, in particular the shape recovery ratio and ΔTrec were superior to those of analogous polymer networks based on linear PLGA dimethacrylates. %0 conference lecture %@ %A Arya, N., Gebauer, T.P., Neffe, A.T., Lendlein, A., Shastri, V.P. %D 2014 %J Tissue Engineering and Regenerative Medicine International Society, Termis 2014 %T Chondrocyte re-differentiation on ethyl lysine diisocyanate cross-linked gelatin based 3-D scaffolds: Application in cartilage tissue engineering %U %X %0 journal article %@ 1022-1352 %A Ghobadi, E., Heuchel, M., Kratz, K., Lendlein, A. %D 2014 %J Macromolecular Chemistry and Physics %N 1 %P 65-75 %R doi:10.1002/macp.201300507 %T Atomistic Simulation of the Shape-Memory Effect in Dry and Water Swollen Poly[(rac-lactide)-co-glycolide] and Copolyester Urethanes Thereof %U https://doi.org/10.1002/macp.201300507 1 %X An atomistic molecular dynamics simulation approach is applied to model the influence of urethane linker units as well as the addition of water molecules on the simulated shape-memory properties of poly[(rac-lactide)-co-glycolide] (PLGA) and PLGA-based copolyester urethanes comprising different urethane linkers. The shape-memory performance of these amorphous packing models is explored in a simulated heating–deformation–cooling–heating procedure. Depending on the type of incorporated urethane linker, the mechanical properties of the dry copolyester urethanes are found to be significantly improved compared with PLGA, which can be attributed to the number of intermolecular hydrogen bonds between the urethane units. Good shape-memory properties are observed for all the modeled systems. In the dry state, the shape fixation is found to be improved by implementation of urethane units. After swelling of the copolymer models with water, which results in a reduction of their glass transition temperatures, the relaxation kinetics during unloading and shape recovery are found to be substantially accelerated. %0 journal article %@ 1613-6810 %A Wischke, C., Schossig, M., Lendlein, A. %D 2014 %J Small %N 1 %P 83-87 %R doi:10.1002/smll.201202213 %T Shape-Memory Effect of Micro-/Nanoparticles from Thermoplastic Multiblock Copolymers %U https://doi.org/10.1002/smll.201202213 1 %X The miniaturization and retained full shape-memory functionality with particle switching to different predefined shapes is reported for semi-crystalline multiblock copolymer matrices with all dimensions in the low micrometer-range. A matrix size-induced reduction of crystallinity suggests limitations of functionality in the low nanometer range. Applications as actuators in microdevices or as microcarriers with switchable shapes for modulated biorecognition are suggested. %0 journal article %@ 1022-1352 %A Schoene, A.-C., Schulz, B., Richau, K., Kratz, K., Lendlein, A. %D 2014 %J Macromolecular Chemistry and Physics %N 24 %P 2437-2445 %R doi:10.1002/macp.201400377 %T Characterization of Langmuir Films Prepared from Copolyesterurethanes Based on Oligo(Ômega-pentadecalactone) and Oligo(Epsilon-caprolactone) Segments %U https://doi.org/10.1002/macp.201400377 24 %X A series of multiblock copolymers (PDLCL) synthesized from oligo(ω-pentadecalactone)diol (OPDL) and oligo(ε-caprolactone)diol (OCL), which are linked by 2,2(4),4-trimethyl-hexa­methylene diisocyanate (TMDI), is investigated by the Langmuir monolayer technique at the air–water interface. Brewster angle microscopy (BAM) and spectroscopic ellipsometry are employed to characterize the polymer film morphologies in situ. PDLCL containing ≥40 wt% OCL segments form homogeneous Langmuir monofilms after spreading. The film elasticity modulus decreases with increasing amounts of OPDL segments in the copolymer. In contrast, the OCL-free polyesterurethane OPDL-TMDI cannot be spread to monomolecular films on the water surface properly, and movable slabs are observed by BAM even at low surface pressures. The results of the in situ morphological characterization clearly show that essential information concerning the reliability of Langmuir monolayer degradation (LMD) experiments cannot be obtained from the evaluation of the π–A isotherms only. Consequently, in situ morphological characterization turns out to be indispensable for characterization of Langmuir layers before LMD experiments. %0 journal article %@ 1022-1360 %A Jiang, Y., Fang, L., Kratz, K., Lendlein, A. %D 2014 %J Macromolecular Symposia %N 1 %P 75-82 %R doi:10.1002/masy.201400142 %T Effect of the Fixation Temperature Tlow on the Crystallization Behavior and Shape-Memory Performance of Crystallizable Copolyesterurethanes %U https://doi.org/10.1002/masy.201400142 1 %X Multiblock copolymers (PDLCL) composed of crystallizable poly(ω-pentadecalactone) (PPDL) segments forming hard domains and crystallizable poly(ε-caprolactone) (PCL) segments forming switching domains, have been recently introduced as multifunctional shape-memory material. The shape-memory properties of PDLCL are related to the crystallization and melting behavior of PCL switching domains, which enable the temporary fixation of an applied deformation via crystallization as well as the recovery of the original shape by melting of the PCL crystals upon heating. In this work, we explored the effect of different fixation temperatures (Tlow = 0, 10, 20 and 25 °C) on the crystallization behavior of PCL domains in compression-molded films prepared from PDLCL with identical weight contents of PCL and PPDL segments in the starting composition by atomic force microscopy (AFM) and differential scanning calorimetry (DSC). The results demonstrated that lower Tlows ≤ 10 °C supported the nucleation of PCL domains, while a Tlow ≥ 20 °C facilitated the growth of PCL crystals. Reducing Tlow, on one hand, increased the degree of crystallinity of PCL domains, which resultantly improved the shape fixation ratio (Rf) from 83% at 25 °C to 89% at 0 °C. Furthermore, the onset temperature of the recovery process (Ts) related to the crystalline PCL domains, was shifted from Ts = 29 °C to 14 °C when Tlow decreased from 25 to 0 °C, causing an increase in the width of the shape-memory transition. In contrast, the shape recovery ratio, with constant high values of Rr ≥ 96% and the almost identical characteristic switching temperature at Tsw ≈ 42 °C, were found to be independent from the applied Tlow. The obtained results confirmed that the shape-memory performance of multiblock copolymers with crystallizable switching domains can be tailored by altering the fixation temperature during programming. %0 editorial %@ 2192-2659 %A Lendlein, A., Neffe, A.T., Jerome, C. %D 2014 %J Advanced Healthcare Materials %N 12 %P 1939-1940 %T Editorial: Advanced Functional Polymers for Medicine %U 12 %X No abstract %0 conference lecture %@ %A Julich-Gruner, K.K., Roch, T., Ma, N., Neffe, A.T., Lendlein, A. %D 2014 %J Advanced Functional Polymers for Medicine, AFPM 2014 %T Synthesis and characterization of star-shaped oligo(ethylene glycol) with tyrosine derived moieties under variation of their molecular weight %U %X %0 journal article %@ 1022-1360 %A Zhang, Q., Sauter, T., Wang, L., Fang, L., Kratz, K., Lendlein, A. %D 2014 %J Macromolecular Symposia %N 1 %P 66-74 %R doi:10.1002/masy.201400140 %T Preparation of Magneto-Sensitive Polymer Nanocomposite Microparticles from Copolyesterurethanes via Electrospraying %U https://doi.org/10.1002/masy.201400140 1 %X Small stimuli-responsive magneto-sensitive microparticles (<5 μm) have attracted broad interest for biomedical applications, since they can be delivered minimal-invasively (e.g. via injection) and guided to a specific site or organ, while using their magnetic properties. In addition, such particles can be remotely heated, e.g., for hyperthermia therapy approaches. In this study, we prepared magneto-sensitive polymer-based nanocomposite microparticles by electrospraying of a 1,1,1,3,3,3 hexafluoro-2-propanol solution containing a mixture of a copolyetheresterurethane (PDC) and magnetic Fe3O4 nanoparticles (MNPs). Thermal gravimetric analysis (TGA) revealed a weight content of 23 ± 0.5 wt-% MNPs in the PDC magneto-sensitive nanocomposite microparticles, which was identical with the initial starting composition. Scanning electron microscopy (SEM) results indicated a bimodal particle size distribution for the prepared magneto-sensitive nanocomposite microparticles around 1.2 ± 0.3 μm and 400 ± 100 nm, respectively. Decreasing the size of the magneto-sensitive nanocomposite microparticles resulted in an increase in their reduced modulus, which was obtained via nanoindentation testing. The PDC magneto-sensitive nanocomposite microparticles could be successfully manipulated in dispersion medium suspension with a permanent magnet, demonstrating their magneto-sensitivity. In addition, the inductive heating capability of the microparticulate nanocomposites could be demonstrated for a thin compression molded test specimen, which could be heated to 44 °C in an alternating magnetic field. The results indicated that such magneto-sensitive nanocomposite microparticles can be potentially used as magneto-responsive shape-memory microparticles for on-demand and remotely controlled drug delivery. %0 journal article %@ 1022-1360 %A Lendlein, A., Behl, M., Domb, A.J. %D 2014 %J Macromolecular Symposia %N 1 %P 7 %R doi:10.1002/masy.201470041 %T Preface %U https://doi.org/10.1002/masy.201470041 1 %X No abstract %0 journal article %@ 1022-1352 %A Baudis, S., Behl, M., Lendlein, A. %D 2014 %J Macromolecular Chemistry and Physics %N 24 %P 2399-2402 %R doi:10.1002/macp.201400561 %T Smart Polymers for Biomedical Applications %U https://doi.org/10.1002/macp.201400561 24 %X nanocarriers for the targeted administration of drugs or genes. %0 journal article %@ 1022-1352 %A Noechel, U., Kumar, U.N., Wang, K., Kratz, K., Behl, M., Lendlein, A. %D 2014 %J Macromolecular Chemistry and Physics %N 24 %P 2446-2456 %R doi:10.1002/macp.201400445 %T Triple-Shape Effect with Adjustable Switching Temperatures in Crosslinked Poly[ethylene-co-(vinyl acetate)] %U https://doi.org/10.1002/macp.201400445 24 %X A triple-shape capability of copolymer networks enabling a variation of the two switching temperatures Tsws by purely physical functionalization is introduced. The polymer networks obtained by covalently crosslinking of poly[ethylene-co-(vinyl acetate)] exhibit a broad melting transition. The influence of the two deformation temperatures Tdeforms applied during programming of the triple-shape effect (TSE) on the two Tsws is explored. Interestingly, it turns out that the deformation geometry plays an important role in the realizability of this concept. Tensile deformations allow adjusting only one Tsw in the lower melting temperature range of 45 to 60 °C, whereas in bending tests, both Tsws can be varied. Finally, two independent TSEs associated to four different Tsws between 45 and 90 °C can be realized in the same specimen. Shape fixity and shape recovery ratios generally exceed 90%, demonstrating an excellent performance of the triple-shape function. %0 journal article %@ 1438-7492 %A Baudis, S., Lendlein, A., Behl, M. %D 2014 %J Macromolecular Materials and Engineering %N 11 %P 1292-1297 %R doi:10.1002/mame.201400073 %T High Throughput Characterization of Polymer Libraries by Diffuse Reflectance Infrared Spectroscopy %U https://doi.org/10.1002/mame.201400073 11 %X Diffuse reflectance FTIR (DRIFT) was established as a high throughput characterization method for classic copolymer systems. Four different methyl methacrylate-based polymer libraries with styrene, N-vinylpyrrolidone, 4-vinylpyridine, or 2-carboxyethyl acrylate as comonomers were synthesized using an automated/robotic synthesizer platform, and analyzed by 1H NMR and DRIFT. By multivariate data analysis both data sets were compared and correlations with R2 between 0.9373 and 0.9971 could be achieved. By this means high throughput screening of comonomer contents of these polymer libraries was enabled. %0 journal article %@ 1022-1360 %A Rijckaert, B., Neffe, A.T., Roch, T., Gebauer, T., Pierce, B.F., Goers, J., Smink, J.J., Gossen, M., Lendlein, A., Leutz, A. %D 2014 %J Macromolecular Symposia %N 1 %P 91-99 %R doi:10.1002/masy.201400147 %T A High Content Screening Assay for Evaluation of Biomaterial-Mediated Cell Fusion Processes %U https://doi.org/10.1002/masy.201400147 1 %X Biomaterials are of increasing importance in regenerative medicine and entail delivery systems in somatic cell therapies, matrices for tissue engineering or tissue regeneration. The evaluation of biomaterial induced biological effects remains a key issue in clinical application. Cell-based assays for potential cytotoxic and immunological responses have been developed but are often inadequate to address cell-type specific responses to biomaterials. To quantitatively monitor attachment, survival, proliferation and fusion-controlled differentiation of osteoclasts (bone resorbing cells), a High Content Screening (HCS) assay has been developed based on osteoclast differentiation of the murine monocytic cell line RAW 264.7. This assay was applied to investigate the influence of degradation products of polymers from gelatin and lysine diisocyanate, which display tailorable mechanical properties and have potential as biomaterials. The data show that the degradation products inhibit formation of multinuclear osteoclasts and suggest a potential support of bone regeneration by suppression of bone resorption. %0 conference lecture %@ %A Neffe, A.T., Lendlein, A. %D 2014 %J Advanced Functional Polymers for Medicine, AFPM 2014 %T Biopolymer-based hydrogels and their evaluation as biomaterials %U %X %0 conference lecture %@ %A Loewenberg, C., Julich-Gruner, K.K., Neffe, A.T, Lendlein, A. %D 2014 %J 2014 MRS Fall Meeting & Exhibit %T Influence of glycidylmethacrylate functional groups attached to gelatin on the formation and properties of hydrogels %U %X %0 conference lecture (invited) %@ %A Lendlein, A., Behl, M., Neffe, A.T. %D 2014 %J 2nd International Conference on Bioinspired and Biobased Chemistry and Materials: Nature Inspires Chemical Engineers, NICE 2014 %T Design of Multifuncational Biomaterials by Chemical Integration of Functions %U %X %0 conference lecture %@ %A Friess, F., Lendlein, A., Wischke, C. %D 2014 %J 6th Forum on New Materials: Symposium Smart Polymers for Biomedical Applications, CIMTEC 2014 %T Microparticles from Photocrosslinked Polyesters %U %X %0 conference lecture %@ %A Balk, M., Behl, M., Noechel, U., Lendlein, A. %D 2014 %J 6th Forum on New Materials: Symposium Smart Polymers for Biomedical Applications, CIMTEC 2014 %T Oligotetrahydrofurane Based Shape-memory Hydrogels %U %X %0 conference poster %@ %A Racheva, M., Romero, O., Julich-Gruner, K.K., Ulrich, A.S., Wischke, C., Lendlein, A. %D 2014 %J Advanced Functional Polymers for Medicine, AFPM 2014 %T Purity of tyrosinase as biocatalyst for hydrogels affects the stability of therapeutic peptides %U %X %0 conference lecture %@ %A Behl, M., Kratz, K., Noechel, U., Lendlein, A. %D 2014 %J 6th Forum on New Materials: Symposium Smart Polymers for Biomedical Applications, CIMTEC 2014 %T Reversible Actuation of Polymer Networks by Directed Crystallization %U %X %0 conference poster %@ %A Balk, M., Behl, M., Noechel, U., Lendlein, A. %D 2014 %J BCS Berliner Chemie Symposium / JCF Jungchemiker Forum %T Shape-Memory Hydrogels with Crystallizable Oligotetrahydrofuran Side Chains %U %X %0 conference lecture (invited) %@ %A Behl, M., Kratz, K., Noechel, U., Sauter, T., Lendlein, A. %D 2014 %J 248th ACS National Meeting & Exposition %T Polymer networks capable of reversible shape-memory effects %U %X %0 conference lecture %@ %A Li, Z., Wang, W., Kratz, K., Xu, X., Roch, M., Kurtz, A., Gossen, M., jung, F., Ma, N., Lendlein, A. %D 2014 %J 6th Forum on New Materials: Symposium Smart Polymers for Biomedical Applications, CIMTEC 2014 %T Scaffold Roughness Regulates the Endothelial Differentiation of Human Adipose Derived Mesenchymal Stem Cells %U %X %0 conference lecture %@ %A Lendlein, A. %D 2014 %J Kunststoffe in der Medizintechnik, VDI Wissensforum %T Aktive, multifunktionale, polymerbasierte Biomaterialien %U %X %0 conference lecture (invited) %@ %A Razzaq, M.Y., Lendlein, A. %D 2014 %J International Conference Smart functional materials for shaping our future %T Internal Structuring on Different Length Scales as Powerful Tool for Creating Shape-Memory Functions in Polymer-Based Materials %U %X %0 conference paper %@ %A Lendlein, A. %D 2014 %J Book of Abstracts, International Conference Smart functional materials for shaping our future %P 63-64 %T Internal Structuring on Different Length Scales as Powerful Tool for Creating Shape-Memory Functions in Polymer-Based Materials %U %X %0 conference lecture %@ %A Wischke, C., Loebler, M., Neffe, A.T., Hanh, B.D., Sternberg, K., Stachs, O., Guthoff, R., Lendlein, A. %D 2014 %J Jahrestagung Deutsche Pharmazeutische Gesellschaft 2014 %T A polymeric multifunctional glaucoma implant %U %X %0 conference lecture %@ %A Zhang, P., Behl, M., Lendlein, A. %D 2014 %J 6th Forum on New Materials: Symposium Smart Polymers for Biomedical Applications, CIMTEC 2014 %T Chemo-responsive Polymer Networks Containing Coordination Crosslinks and Covalent Netpoints %U %X %0 conference poster %@ %A Julich-Gruner, K.K., Loewenberg, C., Roch, T., Neffe, A.T., Lendlein, A. %D 2014 %J 6th Forum on New Materials: Symposium Smart Polymers for Biomedical Applications, CIMTEC 2014 %T Star-shaped Oligo(Ethylene Glycols) Functionalized with Desaminotyrosine and Desamino Tyrosyl Tyrosine %U %X %0 conference lecture (invited) %@ %A Lendlein, A., Jung, F. %D 2014 %J Biologisierte Medizintechnik, 28. Treffpunkt Medizintechnik %T Biofunktionale Materialsysteme fuer die Medizintechnik %U %X %0 conference lecture %@ %A Kratz, K., Jung, F., Lendlein, A. %D 2014 %J 33. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Development of shape-memory polymer-based Implants at HZG %U %X %0 conference lecture (invited) %@ %A Behl, M., Lendlein, A. %D 2014 %J Hangzhou International Polymer Forum, HIPF %T Knowledge-based Design of Actively Moving Polymer Networks %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2014 %J 2014 MRS Fall Meeting & Exhibit %T Strategies for Creating Functions in Polymer-based Materials by Combining Different Components %U %X %0 conference lecture %@ %A Wang, W., Xu, X., Li, Z., Lendlein, A., Ma, N. %D 2014 %J 33. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Genetic engineering of mesenchymal stem cells by non-viral gene delivery %U %X %0 conference lecture %@ %A Franke, R.P., Scharnweber, T., Fuhtmann, R., Mrowietz, C., Wenzel, F., Krueger, A., Jung, F., Lendlein, A. %D 2014 %J 33. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Radiographic contrast media alterate the localization of actin/band4.9 in the membrane cytoskeleton of human erythrocytes %U %X %0 conference poster %@ %A Braune, S., Jung, F., Lendlein, A. %D 2014 %J Biologisierte Medizintechnik, 28. Treffpunkt Medizintechnik %T Investigation of in vitro and in vivo hemocompatibility %U %X %0 conference lecture %@ %A Gebauer, T., Neffe, A.T., Lendlein, A. %D 2014 %J 33. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Single Protein Adsorption to Hydrogels Obtained from Gelatin and a Diisocyanate %U %X %0 conference poster %@ %A Loewenberg, C., Julich-Gruner, K.K., Neffe, A.T, Lendlein, A. %D 2014 %J 2014 MRS Fall Meeting & Exhibit %T Synthesis and Characterization of Polymer Networks Based on Glycidylmethacrylated Gelatin %U %X %0 conference lecture %@ %A Razzaq, M., Behl, M., Nöchel, U., Lendlein, A. %D 2014 %J 2014 MRS Fall Meeting; Symp. B Multifunctional Polymeric and Hybrid Materials %T Magneto-sensitive hybrid nanocomposites based on oligo(omega-pentadecalactone) and covalently integrated magnetic nanoparticles %U %X %0 conference poster %@ %A Wischke, C., Mathew, S., Roch, T., Krueger, A., Lendlein, A. %D 2014 %J BioBarriers 2014 %T Active Particulate Polymer Carriers %U %X %0 conference lecture (invited) %@ %A Lendlein, A., Wischke, C. %D 2014 %J 13th European Symposium on Controlled Drug Delivery, ESCDD 2014 %T Active Polymers and Carriers %U %X %0 conference lecture %@ %A Racheva, M., Julich-Gruner, K.K., Neffe, A.T., Wischke, C., Lendlein, A. %D 2014 %J 2014 MRS Fall Meeting & Exhibit %T Functionalization Degree of Telechelics as a Structural Parameter to Influence the Properties of Enzymatically Formed Polyethylene Glycol Based Networks %U %X %0 conference lecture %@ %A Heuchel, M., Razzaq, M., Kratz, K., Behl, M., Lendlein, A. %D 2014 %J 2014 MRS Fall Meeting; Symp. B Multifunctional Polymeric and Hybrid Materials %T Modeling the heat transfer behavior of magnetosensitive shape-polymer nanocomposites with changing surface area to volume ratios %U %X %0 conference lecture %@ %A Kratz, K., Behl, M., Nöchel, U., Lendlein, A. %D 2014 %J 2014 MRS Fall Meeting; Symp. B Multifunctional Polymeric and Hybrid Materials %T Crystallizable Polymer Networks Capable of Reversible Shape-Memory- Effects %U %X %0 conference lecture %@ %A Wischke, C., Weigel, J., Lendlein, A. %D 2014 %J 2014 MRS Fall Meeting & Exhibit %T Poly(n-butylcyanoacrylate) Nanoparticles as Carriers for Adenosine triphosphate %U %X %0 conference poster %@ %A Baudis, S., Lendlein, A., Behl, M. %D 2014 %J 2014 MRS Fall Meeting & Exhibit %T Robotic Synthesis of Polyester- and Depsipeptide- based Polyurethanes %U %X %0 conference poster %@ %A Wischke, C., Mathew, S., Roch, T., Lendlein, A. %D 2014 %J 9th World Meeting on Pharmaceutics, Biopharmaceutics and Pharmaceutical Technology %T Microparticles as carriers for phagocytosis and modulation of immune cells %U %X %0 conference lecture %@ %A Neffe, A.T., Lendlein, A. %D 2014 %J 2014 MRS Fall Meeting & Exhibit %T Mechanic Studies of Gelatin Crosslinking %U %X %0 conference poster %@ %A Schroeter, M., Koksch, B., Ma, N., Lendlein, A. %D 2014 %J BCS Berliner Chemie Symposium / JCF Jungchemiker Forum %T Helmholtz Graduate School for Macromolecular Bioscience %U %X %0 conference poster %@ %A Yan, W., Fang, L., Heuchel, M., Kratz, K., Lendlein, A. %D 2014 %J Advanced Functional Polymers for Medicine, AFPM 2014 %T Modeling of Stress Relaxation of a Semi-Crystalline Multiblock Copolymer and its Deformation Behavior %U %X %0 conference lecture %@ %A Racheva, M., Romero, O., Julich-Gruner, K.K., Ulrich, A.S., Wischke, C., Lendlein, A. %D 2014 %J 2014 MRS Fall Meeting & Exhibit %T Purity of mushroom tyrosinase as a biocatalyst for biomaterial synthesis affects the stability of therapeutic peptides %U %X %0 conference lecture %@ %A Hao, X., Lv, J., Li, Q., Fan, J., Feng, Y., Behl, M., Lendlein, A. %D 2014 %J 3rd Symposium on Innovative Polymers for Controlled Delivery, SIPCD 2014 %T REDV-linked biodegradable polymeric micelles as the transfer vector of ZNF580 for the proliferation of endothelial cells %U %X %0 conference lecture %@ %A Heuchel, M., Al-Qaisi, L., Kratz, K., Noechel, U., Behl, M., Lendlein, A. %D 2014 %J 2014 MRS Fall Meeting & Exhibit %T Thermomechanical Characterization of a Series of Crosslinked Poly[ethylene-co-(vinyl acetate)] (PEVA) Copolymers %U %X %0 conference lecture %@ %A Noechel, U., Kratz, K., Behl, M., Lendlein, A. %D 2014 %J 2014 MRS Fall Meeting & Exhibit, Symposium B %T Relation -between Nanostructural Changes and Macroscopic Effects during Reversible Temperature-Memory Effect under Stress-Free Conditions in Semicrystalline Polymer Networks %U %X %0 conference lecture %@ %A Baudis, S., Lendlein, A., Behl, M. %D 2014 %J 2014 MRS Fall Meeting & Exhibit, Symposium B %T Robot Assisted Synthesis and Characterization of Polyester-based Polyurethanes %U %X %0 conference lecture %@ %A Razzaq, M.Y., Behl, M., Lendlein, A. %D 2014 %J 2014 MRS Fall Meeting & Exhibit, Symposium B %T Thermally Controlled Shape-Memory Investigations of Nanocomposites Based on Oligo(ω-pentadecalactone) and Magnetic Nanoparticles Acting as Crosslinks %U %X %0 conference lecture %@ %A Neffe, A.T., Lendlein, A. %D 2014 %J Vortrag im Industriemuseum Teltow %T Multifunktionale Polymere - Zukunftsperspektiven fuer Materialien in der Medizin %U %X %0 conference lecture (invited) %@ %A Kratz, K., Behl, M., Noechel, U., Sauter, T., Lendlein, A. %D 2014 %J Polymermischungen 2014, Polymerblends und Nanocomposites %T Reversible Shape- Memory- Effects in Polymer Networks %U %X %0 conference lecture (invited) %@ %A Behl, M., Razzaq, M., Kratz, K., Lendlein, A. %D 2014 %J SPIE BiOS 2014 %T Magnetically triggered active Hybrid- Nanocomposites %U %X %0 conference poster %@ %A Wischke, C., Lendlein, A. %D 2014 %J SPIE BiOS 2014 %T Stimuli-induced, directed actuation of micro/nanaoparticles from a multiblock copolyester urethane %U %X %0 conference lecture %@ %A Behl, M., Balk, M., Nöchel, U., Lendlein, A. %D 2014 %J MRS Fall Meeting 2014 %T Dual-Shape Hydrogels with Crystallizable; Oligomeric Switching Segments %U %X %0 conference poster %@ %A Fang, L., Wischke, C., Kratz, K., Lendlein, A. %D 2014 %J Advanced Functional Polymers for Medicine, AFPM 2014 %T Influence of Film Thickness on the Morphology of a Copolyesterurethane Comprising Crystallizable Poly(Epsilon-caprolactone) Segments %U %X %0 conference lecture %@ %A Wang, L., Baudis, S., Kratz, K., Lendlein, A. %D 2014 %J 2nd International Conference on Bioinspired and Biobased Chemistry and Materials: Nature Inspires Chemical Engineers, NICE 2014 %T Characterization of bi-layered magnetic nanoparticles synthesized via two-step surface-initiated ring-opening polymerization %U %X %0 conference poster %@ %A Xu, X., Wang, W., Kratz, K., Fang, L., Li, Z., Kurtz, A., Ma, N., Lendlein, A. %D 2014 %J Advanced Functional Polymers for Medicine, AFPM 2014 %T 3D geometric cues regulate stem cell self-renewal, migration and differentiation %U %X %0 conference poster %@ %A Neffe, A.T., Julich-Gruner, K.K., Roch, T., Garcia Cruz, D.M., Naolou, T., Brunacci, N., Lendlein, A. %D 2014 %J Advanced Functional Polymers for Medicine, AFPM 2014 %T End group functionalized starshaped oligo(ethylene glycols) and their biological evaluation %U %X %0 conference poster %@ %A Roch, T., Ma, N., Kratz, K., Lendlein, A. %D 2014 %J Advanced Functional Polymers for Medicine, AFPM 2014 %T Cell-based detection of microbial biomaterial contaminations %U %X %0 conference lecture %@ %A Braune, S., Dietze, S., Roch, T., Krueger, A., Baudis, S., Behl, M., Kratz, K., Jung, F., Lendlein, A. %D 2014 %J 6th Forum on New Materials: Symposium Smart Polymers for Biomedical Applications, CIMTEC 2014 %T Bicompatibility of a Degradable Poly[(L-lactide)-coglycolide] Network %U %X %0 conference poster %@ %A Wischke, C., Neffe, A.T., Loebler, M., Sternberg, K., Stachs, O., Guthoff, R., Lendlein, A. %D 2014 %J 13th European Symposium on Controlled Drug Delivery, ESCDD 2014 %T A polymeric multifunctional glaucoma implant %U %X %0 conference poster %@ %A Rossberg, J., Schulz, B., Kratz, K., Lendlein, A. %D 2014 %J Advanced Functional Polymers for Medicine, AFPM 2014 %T Interactions of Langmuir monolayers based on boronic acid end-capped oligo(ε-caprolactone) with saccharides as model compounds for diol containing biomolecules %U %X %0 journal article %@ 1386-0291 %A Krueger, A., Goers, J., Zaupa, A., Loewenberg, C., Pierce, B.F., Wischke, C., Neffe, A.T., Jung, F., Lendlein, A. %D 2013 %J Clinical Hemorheology and Microcirculation %N 1 %P 133-142 %R doi:10.3233/CH-131697 %T Influence of physically crosslinked gelatins on the vasculature in the avian chorioallantoic membrane %U https://doi.org/10.3233/CH-131697 1 %X Gelatins functionalized with desaminotyrosine (DAT) or desaminotyrosyl tyrosine (DATT) form physically crosslinked hydrogels, due to the interactions between the introduced aromatic moieties and gelatin triple helices, whose extent depends on the thermal treatment of the material. The G-modulus of these hydrogels can be tailored to the range of the natural extracellular matrix by adjusting the degree of crosslinking. While these gelatin-based materials have been shown to be not angiogenic, the aim of the study was to evaluate whether these biomaterials influence the regulation of blood vessels when positioned on the chorionallantoic membrane (CAM) of fertilized eggs. The results clearly indicate that the DAT-functionalized gelatin led to an increase of the diameter of the blood vessels in the CAM, which at the same time is probably associated with an increased blood flow in these CAM vessels. The vessel diameters of the four groups (DAT-functionalized gelatin, DATT-functionalized gelatin, plain gelatin, control group without gelatin, each n = 10) differed significantly (p < 0.0001). Vessels in the CAM exposed to the DAT-functionalized gelatin showed with 36.4 μm ± 3.4 μm the largest mean diameters compared to the mean diameters of the samples exposed to DATT gelatin (16.0 μm ± 0.8 μm; p < 0.05) and the plain gelatin (21.2 μm ± 1.0 μm; p < 0.05), which both did not differ significantly from the vessels of the control group. The biocompatibility of the materials in vitro motivates the exploration of their application as matrix in local drug-release systems with short half-life times (one hour up to several days). %0 conference lecture %@ %A Rueder, C., Sauter, T., Kratz, K., Haase, T., Peter, J., Jung, F., Lendlein, A., Zohlnhoefer, D. %D 2013 %J 32. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Influence of fiber diameter and orientation of electrospun copolyetheresterurethanes on smooth muscle and endothelial cell behaviour %U %X %0 conference lecture %@ %A Roch, T., Schulz, C., Jung, F., Ma, N., Lendlein, A. %D 2013 %J 32. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Interaction of poly(ether imide) films with early immune mechanisms %U %X %0 conference lecture %@ %A Li, Z., Ma, N., Kratz, K., Wang, W., Xu, X., Gossen, M., Roch, T., Kurtz, A., Lendlein, A. %D 2013 %J 32. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Effects of Roughness on Angiogenesis of Human Adipose Derived Stem Cells %U %X %0 journal article %@ 1386-0291 %A Xu, X., Kratz, K., Wang, W., Li, Z., Roch, T., Jung, F., Lendlein, A., Ma, N. %D 2013 %J Clinical Hemorheology and Microcirculation %N 1 %P 143-156 %R doi:10.3233/CH-131698 %T Cultivation and spontaneous differentiation of rat bone marrow-derived mesenchymal stem cells on polymeric surfaces %U https://doi.org/10.3233/CH-131698 1 %X Accumulating evidence demonstrated many physical and chemical cues from the local microenvironment could influence mesenchymal stem cells (MSCs) maintenance and differentiation. In this study, we systematically investigated the interaction of rat bone marrow-derived mesenchymal stem cells (rBMSCs) and polymeric substrates. Adhesion, proliferative capacity, cytoskeleton alteration, cytotoxicity, apoptosis, senescence, and adipogenesis potential of rBMSCs were determined on these polymeric inserts prepared from polyetherurethane (PEU) and poly(ether imide) (PEI). Inserts for culture plates were applied to ensure that the rBMSCs were solely in contact to the tested material. The explored inserts exhibited advancing contact angles of 84° (PEU) and 93° (PEI). Finally, the micromechanical properties determined by atomic force microscopy (AFM) indentation varied in the range from 6 GPa (PEU) to 13 GPa (PEI). We found that both PEU and PEI showed a good cell compatibility to rBMSCs. rBMSCs could adherent on both polymeric surfaces with the similar adhesion ratio and subsequent division rate. However, cells cultured on PEU exhibited higher apoptosis level and senescence ratio, which resulted in lower cell density (22061 ± 3000/cm2) compared to that on PEI (68395 ± 8000/cm2) after 20 days cultivation. Morphological differences of rBMSCs were detected after 5 days cultivation. Cells on PEU exhibited flat and enlarged shape with rearranged filamentous actin (F-actin) cytoskeleton, while cells on PEI and tissue culture plate (TCP) had similar spindle-shape morphology and oriented F-actin. After 20 days, lipid droplets were spontaneously formed in rBMSCs on PEU and PEI but not on TCP. Both PEU and PEI might trigger rBMSCs towards spontaneous adipogenic commitment, whereas PEI provided better cell compatibility on rBMSCs apoptosis, senescence and proliferation. %0 journal article %@ 1022-1352 %A Lendlein, A., Sauter, T. %D 2013 %J Macromolecular Chemistry and Physics %N 11 %P 1175-1177 %R doi:10.1002/macp.201300098 %T Shape-Memory Effect in Polymers %U https://doi.org/10.1002/macp.201300098 11 %X No abstract %0 journal article %@ 1386-0291 %A Krueger, A., Mrowietz, C., Lendlein, A., Jung, F. %D 2013 %J Clinical Hemorheology and Microcirculation %N 1 %P 111-120 %R doi:10.3233/CH-131695 %T Interaction of human umbilical vein endothelial cells (HUVEC) with platelets in vitro: Influence of platelet concentration and reactivity %U https://doi.org/10.3233/CH-131695 1 %X Endothelialisation of polymer-based cardiovascular implants is one strategy to render biomaterials hemocompatible. The evaluation of the functionality and the confluence of an endothelial cell (EC) monolayer in vitro is therefore of crucial importance, because a non-functional or non-confluent EC monolayer can contribute to the failure of vascular grafts. Moreover, the comparison of different potential biomaterials regarding their ability to induce the formation of a functional confluent EC monolayer is of great value. Most of the currently reported in vitro studies focus on direct or indirect markers of EC behaviour. However, these studies still lack the final proof that the EC monolayer, which can be developed on polymers is confluent and functional. In this study, we investigated the suitability of an in vitro co-culture of human umbilical vein endothelial cells (HUVEC) with platelets to predict the functionality of an EC monolayer. The interaction of platelets with HUVEC was evaluated depending on the concentration of the platelets in the added plasma and of the reactivity of the platelets to pharmacological stimuli. For this purpose, HUVEC were seeded in a 24 well plate. After three days of cultivation, platelets were added to the HUVEC cell culture medium to final concentrations of 200, 2,000 or 20,000 platelets/μl (n = 7 each). The platelets were processed immediately after blood collection and added to the HUVEC culture after a 30 minutes resting period. As a first control, an EC monolayer just cultured with EC medium was used. As a second control EC supplemented with plasma without platelets were applied. The HUVEC monolayer was investigated microscopically after 1 hour of platelet exposition. The addition of thrombocytes to EC affected the EC adherence dependent on the initial cell seeding number of HUVEC, the platelet concentration and also on the reactivity of platelets added. In both controls no significant EC detachment was detected. The results demonstrated a significant influence of platelet concentration and reactivity on the adherence of EC in a static model. %0 conference lecture %@ %A Behl, M., Kratz, K., Noechel, U., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Reversible, Bidirectional Shape-memory Polymers by Directed Crystallization %U %X %0 journal article %@ 1386-0291 %A Jung, F., Braune, S., Lendlein, A. %D 2013 %J Clinical Hemorheology and Microcirculation %N 1-2 %P 97-115 %R doi:10.3233/CH-2012-1579 %T Haemocompatibility testing of biomaterials using human platelets %U https://doi.org/10.3233/CH-2012-1579 1-2 %X Cardiovascular implants are increasingly important in regenerative medicine. To improve the safety and function of blood-contacting implants a major need exists for new polymer-based biomaterials that avoid adverse reactions, particularly thrombotic events. This review is aimed to summarize the multi-stepped and interlinked processes leading to a thrombus growth on body foreign surfaces: protein adsorption, platelet adhesion accompanied by activation and spreading and the release of substances of various organelles activating other neighboured platelets (and the plasmatic coagulation) leading to the formation of a plug of platelets and, finally, to a thrombus. %0 conference lecture %@ %A Santan, H., Wischke, C., Neffe, A., Lendlein, A. %D 2013 %J HVI Method Workshop 2013 %T Protein Adsorption to Synthetic Polymers %U %X %0 journal article %@ 1386-0291 %A Braune, S., Ruesten-Lange, M.v., Mrowietz, C., Luetzow, K., Roch, T., Neffe, A.T., Lendlein, A., Jung, F. %D 2013 %J Clinical Hemorheology and Microcirculation %N 3 %P 235-248 %R doi:10.3233/CH-131729 %T Dynamic in vitro hemocompatibility testing of poly(ether imide) membranes functionalized with linear, methylated oligoglycerol and oligo(ethylene glycol) %U https://doi.org/10.3233/CH-131729 3 %X Linear, side-chain methylated oligoglycerols (OGMe) were recently reported as potential surface passivating molecules for improving the protein resistance of cardiovascular application relevant poly(ether imide) (PEI) membranes. A previously reported in vitro screening under static test conditions allowed an end-point evaluation of the adhesion and activation of adherent thrombocytes performed on the material surfaces and revealed similar levels of thrombogenicity on PEI membranes, functionalized with OGMe and oligo(ethylene glycol) (OEG) of similar molecular weight (Mn = 1,300 g·mol−1 - 1,800 g·mol−1). In the present study, we investigated the hemocompatibility of these materials in a dynamic closed loop system, in order to study time-dependent thrombocyte material interactions also of the circulating thrombocytes by mimicking in vivo relevant flow conditions in a dynamic test system with multiple material contacts. Activation and aggregation of circulating thrombocytes as well as complement activation and plasmatic coagulation were evaluated after 40 circulations of thrombocyte rich plasma in the closed loop system. The results of the dynamic tests revealed no differences between the OGMe and OEG functionalized PEI membranes. Furthermore, no differences were observed between the latter and a PEI membrane treated under the conditions of functionalization at pH 11 (PEI-pH11) without an oligoether being present. Blood plasma protein adsorption, as well as activation, and adherence of circulating thrombocytes occurred in a comparable, but minor manner on all investigated PEI membranes. From this we conclude that the OGMe and OEG surface functionalization did not lead to an improvement of the already good hemocompatibility of the PEI-pH11 membrane. %0 journal article %@ 1022-1352 %A Julich-Gruner, K.K., Loewenberg, C., Neffe, A.T., Behl, M., Lendlein, A. %D 2013 %J Macromolecular Chemistry and Physics %N 5 %P 527-536 %R doi:10.1002/macp.201200607 %T Recent Trends in the Chemistry of Shape-Memory Polymers %U https://doi.org/10.1002/macp.201200607 5 %X Shape-memory polymers (SMPs) are stimuli-sensitive materials capable of performing complex movements on demand, which makes them interesting candidates for various applications, for example, in biomedicine or aerospace. This trend article highlights current approaches in the chemistry of SMPs, such as tailored segment chemistry to integrate additional functions and novel synthetic routes toward permanent and temporary netpoints. Multiphase polymer networks and multimaterial systems illustrate that SMPs can be constructed as a modular system of different building blocks and netpoints. Future developments are aiming at multifunctional and multistimuli-sensitive SMPs. %0 conference lecture %@ %A Wischke, C., Friess, F., Lendlein, A. %D 2013 %J 2013 MRS Spring Meeting and Exhibit, Symposium MM – Advanced Materials for Biological and Biomedical Applications %T Morphology of crosslinked poly(Epsilon-caprolactone) particles %U %X %0 journal article %@ 1558-3724 %A Sauter, T., Heuchel, M., Kratz, K., Lendlein, A. %D 2013 %J Polymer Reviews %N 1 %P 6-40 %R doi:10.1080/15583724.2012.756519 %T Quantifying the Shape-Memory Effect of Polymers by Cyclic Thermomechanical Tests %U https://doi.org/10.1080/15583724.2012.756519 1 %X Shape-memory polymers (SMPs) can be deformed and fixed in defined temporary shapes, which significantly differ from their original shape and remain unchanged until exposed to heat or other stimuli. The shape-memory effect (SME) of polymers is generally quantified in cyclic thermomechanical experiments, which allow to simultaneously control stress or strain and temperature during programming and recovery. Characteristic shape-memory quantities such as the shape-fixity ratio R f and shape-recovery ratio R r as well as the specific response temperatures can be determined from the obtained stress-temperature-strain curves. This review reports on the most common cyclic testing methods utilizing tensile, bending, and compression experiments for examination of dual-shape polymers. Furthermore, recently developed testing protocols for triple- and multi-shape polymers as well as materials that exhibit a temperature-memory effect or can show a two-way SME under constant stress are discussed. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2013 %J Advanced Functional Polymers for Medicine, 533th WE-Heraeus-Seminar %T Recent Trends in Shape-Memory Polymer Research - Multistimuli-sensitivity, Multishape Capability and Reversible Effects %U %X %0 journal article %@ 0887-6266 %A Heuchel, M., Sauter, T., Kratz, K., Lendlein, A. %D 2013 %J Journal of Polymer Science B %N 8 %P 621-637 %R doi:10.1002/polb.23251 %T Thermally induced shape-memory effects in polymers: Quantification and related modeling approaches %U https://doi.org/10.1002/polb.23251 8 %X Thermo-sensitive polymers, which are capable to exhibit a dual-, triple-, or multi-shape effect or a temperature-memory effect (TME), characterized by a controlled shape change in a predefined way, are of current technological interest for designing and realization of actively moving intelligent devices. Here, the methods for the quantitative characterization of shape-memory effects in polymers and recently developed thermomechanical modeling approaches for the simulation of dual-, triple-, and multi-shape polymers as well as materials that exhibit a TME are discussed and some application oriented models are presented. Standardized methods for comprehensive quantification of the different effects and reliable modeling approaches form the basis for a successful translation of the extraordinary achievements of fundamental research into technological applications. %0 journal article %@ 0014-3057 %A Noechel, U., Reddy, C.S., Uttamchand, N.K., Kratz, K., Behl, M., Lendlein, A. %D 2013 %J European Polymer Journal %N 9 %P 2457-2466 %R doi:10.1016/j.eurpolymj.2013.01.022 %T Shape-memory properties of hydrogels having a poly(Epsilon-caprolactone) crosslinker and switching segment in an aqueous environment %U https://doi.org/10.1016/j.eurpolymj.2013.01.022 9 %X Here we study the thermomechanical properties as well as the shape-memory behavior of a series of CLEG copolymer networks in an aqueous environment. The mechanical properties of the networks at 25 °C in aqueous environment were found to increase from 4 MPa to 77 MPa with increasing crosslink density. The shape-memory properties of the copolymer networks were examined in an aqueous environment by both bending as well as uniaxial elongation experiments. Excellent dual-shape properties with high shape fixity ratios around Rf = 79–100% and shape recovery ratios in the range of Rr = 59% to Rr = 100% were obtained for copolymers with a PCLDIMA weight fraction ⩾50 wt% in the starting composition. The swelling of CLEG in H2O resulted in a reduction of the switching temperature. Furthermore the structural changes during programming of CLEG were assessed in situ by small and wide angle X-ray scattering (SAXS, WAXS) experiments, which confirmed that the overall degree of crystallinity as well as the orientation of the crystalline domains controlled the dual-shape performance. We have found that an appropriate switching segment should result in a degree of crystallinity higher than 10–20% to enable high strain fixity ratios. Furthermore, hydrogels having dual shape-memory capability could be created by using semi-crystalline crosslinker simultaneously acting as the switching segment. %0 journal article %@ 1022-1352 %A Sauter, T., Kratz, K., Lendlein, A. %D 2013 %J Macromolecular Chemistry and Physics %N 11 %P 1184-1188 %R doi:10.1002/macp.201300062 %T Pore-Size Distribution Controls Shape-Memory Properties on the Macro- and Microscale of Polymeric Foams %U https://doi.org/10.1002/macp.201300062 11 %X Open porous foams with identical foam density but different pore-size distributions (bimodal or monomodal) are prepared from a shape-memory polyetherurethane (PEU) by thermally induced phase separation. The shape-memory effect of the two PEU foams is explored by cyclic thermomechanical compression tests and microstructural analysis. The obtained results reveal that the PEU foam with a bimodal pore-size distribution exhibits an increased shape-recovery under stress-free conditions, both on the macro- (foam level) as well as the microscale (pore level). While bimodal pore-size distributions induce microscale bending during compression, buckling occurs in foams with monomodal pore-size distributions, leading to both a reduced and delayed shape recovery. %0 conference lecture %@ %A Krueger, A., Trescher, K., Scharnagl, N., Kratz, K., Roch, T., Lendlein, A., Jung, F. %D 2013 %J 32. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %R doi:10.1007/s00382-011-1220-0 %T Adherence and viability of primary human dermal keratinocytes and primary human dermal fibroblasts on acrylonitrile-based copolymers with systematic variations of positively and negatively charged functional groups %U https://doi.org/10.1007/s00382-011-1220-0 %X %0 journal article %@ 1744-683X %A Zhao, Q., Behl, M., Lendlein, A. %D 2013 %J Soft Matter %N 6 %P 1744-1755 %R doi:10.1039/c2sm27077c %T Shape-memory polymers with multiple transitions: Complex actively moving polymers %U https://doi.org/10.1039/c2sm27077c 6 %X Shape-memory polymers (SMPs) are able to perform shape transitions in a pre-defined pathway in response to suitable external stimuli such as heat, magnetism, electricity, moisture, or light. Most of the SMPs are dual-shape materials, which enable a single shape transition from a temporary to a permanent shape. Recently, triple-shape polymers (TSPs), which are capable of accomplishing two shape transitions, as well as multi-shape polymers with shape changes have been introduced including temperature-memory polymers (TMPs) with tunable multiple shape transitions. Different concepts for obtaining multi-shape polymers are introduced and the sophisticated structural design concepts in combination with tailored shape-memory creation processes (SMCPs) are explained. Future opportunities emerge in alternative actuation methods and exploration of potential applications. %0 conference lecture %@ %A Rueder, C., Haase, T., Sauter, T., Kratz, K., Peter, J., Jung, F., Lendlein, A., Zohlnhoefer, D. %D 2013 %J 32. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T In Vivo Assessment of Poly(ether imide) (PEI) Electrospun Scaffold and Film by Subcutaneous Implantation in Mice %U %X %0 conference poster %@ %A Gebauer, T., Neffe, A.T., Lendlein, A. %D 2013 %J 2013 MRS Spring Meeting and Exhibit, Symposium MM – Advanced Materials for Biological and Biomedical Applications %T Influence of diisocyanate reactivity and water solubility on the formation of gelatin-based networks in water %U %X %0 conference lecture %@ %A Ma, N., Xu, X., Kratz, K., Wang, W., Li, Z., Jung, F., Lendlein, A. %D 2013 %J 32. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T The Influence of Geometrically Patterned Polymer Surfaces on the Development of Human Mesenchymal Stem Cells %U %X %0 conference lecture (invited) %@ %A Schulz, B., Lendlein, A. %D 2013 %J 13. Schwarzheider Kunststoffkolloquium %T Polymere fuer die Biomedizin %U %X %0 conference poster %@ %A Wischke, C., Lendlein, A. %D 2013 %J Biotechnologie 2020 plus, 4. Jahreskongress zur BMBF-Initiative %T Multifunktionale Materialien fuer die Biotechnologie %U %X %0 conference poster %@ %A Harmsen, D., Lendlein, A., Schroeter, M., Duvinage, B. %D 2013 %J 28. Tag der Chemie %T Charakterisierung von hydrolytisch teilabgebauten Polymilchsaeure-Folien %U %X %0 conference lecture %@ %A Jung, F., Mrowietz, C., Schulz, C., Blaschke, F., mueller, D., Lendlein, A., Schunk, W.-H. %D 2013 %J 32. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Wirkung von Zytochrom P-450-abhaengigen Eikosanoid-Analoga auf die Ristozetin-induzierte Thrombozytenaggregation %U %X %0 conference lecture %@ %A Braune, S., Alagoez, G., Zhou, S., Roch, T., Kratz, K., Lendlein, A., Jung, F. %D 2013 %J 32. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Static in vitro hemocompatibility testing of hydrophobic poly(n-butyl acrylate) networks with high crosslink densities %U %X %0 conference lecture %@ %A Neffe, A.T., Gebauer, T., Pierce, B.F., Lendlein, A. %D 2013 %J 2013 MRS Spring Meeting and Exhibit %T Controlling Mechanical Properties of Biopolymer-based Materials %U %X %0 conference lecture %@ %A Wischke, C., Neffe, A.T., Ruesten-Lange, M.v., Braune, S., Luetzow, K., Roch, T., Richau, K., Jung, F., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T The Suitability of Polyethers to Reduce Protein Adsorption and to Improve Hemocompatibility %U %X %0 conference lecture %@ %A Kratz, K., Behl, M., Noechel, U., Sauter, T., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Polymer Networks Exhibiting a Reversible Temperature-Memory Effect %U %X %0 journal article %@ 0957-4530 %A Feng, Y., Zhao, H., Behl, M., Lendlein, A., Guo, J., Yang, D. %D 2013 %J Journal of Materials Science: Materials in Medicine %N 1 %P 61-70 %R doi:10.1007/s10856-012-4685-4 %T Grafting of poly(ethylene glycol) monoacrylates on polycarbonateurethane by UV initiated polymerization for improving hemocompatibility %U https://doi.org/10.1007/s10856-012-4685-4 1 %X Poly(ethylene glycol) monoacrylates (PEGMAs) with a molecular weight between 400 and 1,000 g mol−1 were grafted by ultraviolet initiated photopolymerization on the surface of polycarbonateurethane (PCU) for increasing its hydrophilicity and improving its hemocompatibility. The surface-grafted PCU films were characterized by Fourier transformation infrared spectroscopy, X-ray photoelectron spectroscopy, water contact angle, scanning electron microscopy (SEM) and atomic force microscopy measurements. The surface properties of the modified films were studied in dry and wetted state. Blood compatibility of the surfaces was evaluated by platelet adhesion tests and adhered platelets were determined by SEM. The results showed that the hydrophilicity of the films had been increased significantly by grafting PEGMAs, and platelets adhesion onto the film surface was obviously suppressed. Furthermore, the molecular weight of PEGMAs had a great effect on the hydrophilicity and hemocompatibility of the PCU films after surface modification and increased with increasing molecular weight of PEGMAs. %0 conference lecture %@ %A Kratz, K., Lendlein, A. %D 2013 %J Helmholtz Graduate School for Macromolecular Bioscience, Summer School 2013 %T Equipment of Polymers with Memory Effects by Physical Approaches %U %X %0 conference lecture %@ %A Gebauer, T., Neffe, A.T., Lendlein, A. %D 2013 %J HVI Method Workshop 2013 %T Protein Adsorption to Gelatin-based Biomaterials %U %X %0 conference poster %@ %A Fang, L., Yan, W., Noechel, U., Zierke, M., Behl, M., Kratz, K., Lendlein, A. %D 2013 %J 2013 MRS Spring Meeting and Exhibit, Symposium MM – Advanced Materials for Biological and Biomedical Applications %T Influence of Coupling Agent on the Morphology of Multifunctional, Degradable Shape-Memory Polymers %U %X %0 conference lecture %@ %A Roch, T., Schmidt, S., Wischke, C., Mathew, S., Ma, N., Lendlein, A. %D 2013 %J 2013 MRS Spring Meeting and Exhibit %T Modulating dendritic cell responses by particulate carriers loaded with NOD receptor agonits %U %X %0 conference lecture %@ %A Sauter, T., Kratz, K., Lendlein, A. %D 2013 %J 245th National ACS Spring Meeting, Symposium on Stimuli-Responsive Polymers %T Pore Size Distribution as Structural Parameter to Tailor the Shape-Memory Effect of Polyurethane Foams %U %X %0 conference lecture (invited) %@ %A Wischke, C., Lendlein, A. %D 2013 %J World Congress on Regenerative Medicine 2013 %T Multifunctional Biomaterials %U %X %0 lecture %@ %A Roch, T., Lendlein, A. %D 2013 %J %T Zellinteraktionen mit Polymeren für die regenerative Medizin %U %X %0 conference lecture %@ %A Ma, N., Luetzow, C., Kratz, K., Furlani, D., Li, W., Wang, W., Pittermann, E., Neffe, A.T., Sauter, T., Jung, F., Lendlein, A. %D 2013 %J 17th Conference of the European Society for Clinical Hemorheology and Microcirculation, ESCHM 2013 %T A three-dimensional stem cell culture system by polyurethane scaffold material %U %X %0 conference poster %@ %A Tartivel, L., Behl, M., Schroeter, M., Lendlein, A. %D 2013 %J 2013 MRS Spring Meeting and Exhibit, Symposium MM – Advanced Materials for Biological and Biomedical Applications %T ABA triblock copolymer based hydrogels with thermo-sensitivity for biomedical applications %U %X %0 journal article %@ 2280-8000 %A Friess, F., Wischke, C., Behl, M., Lendlein, A. %D 2013 %J Journal of Applied Biomaterials & Functional Materials %N 3 %P 273-279 %R doi:10.5301/JABFM.2012.10372 %T Oligo(Epsilon-caprolactone)-based polymer networks prepared by photocrosslinking in solution %U https://doi.org/10.5301/JABFM.2012.10372 3 %X Purpose: Polymer networks with adjustable properties prepared from endgroup-functionalized oligoesters by UV-crosslinking in melt have evolved into versatile multifunctional biomaterials. In addition to the molecular weight or architecture of precursors, the reaction conditions for crosslinking are pivotal for the polymer network properties. Crosslinking of precursors in solution may facilitate low-temperature processes and are compared here to networks synthesized in melt.
Methods: Oligo(ε-caprolactone)-(z)methacrylate (oCL-(z)IEMA) precursors with a linear (z = di) or a four-armed star-shaped (z = tetra) architecture were crosslinked by radical polymerization in melt or in solution with UV irradiation. The thermal, mechanical, and swelling properties of the polymer networks obtained were characterized.
Results: Crosslinking in solution resulted in materials with lower Young’s moduli (E), lower maximum stress (σmax), and higher elongation at break (εB) as determined at 70 °C. Polymer networks from 8 kDa star-shaped precursors exhibited poor elasticity when synthesized in the melt, but can be established as stretchable materials with a semi-crystalline morphology, a high gel- content, and a high elongation at break when prepared in solution.
Conclusions: The crosslinking condition of methacrylate functionalized precursors significantly affected network properties. For some types of precursors such as star-shaped telechelics, synthesis in solution provided semi-crystalline elastic materials that were not accessible from crosslinking in melt. %0 conference lecture %@ %A Kratz, K., Cui, J., Lendlein, A. %D 2013 %J 245th National ACS Spring Meeting, Symposium on Stimuli-Responsive Polymers %T Temperature-Memory Polymers %U %X %0 conference poster %@ %A Behl, M., Kratz, K., Noechel, U., Zotzmann, J., Lendlein, A. %D 2013 %J Advanced Functional Polymers for Medicine, 533th WE-Heraeus-Seminar %T Directed Crystallization turns Poly(Omega-pentadecalactone)-based Multiphase Polymer Networks into Active Polymers %U %X %0 conference poster %@ %A Friess, F., Lendlein, A., Wischke, C. %D 2013 %J 245th National ACS Spring Meeting, Symposium on Stimuli-Responsive Polymers %T Investigating Side-reactions During UV-induced Preparation of oligo(E-caprolactone) Based Shape-memory Polymer Networks %U %X %0 conference lecture %@ %A Krueger, A., Mayer, A., Roch, T., Schulz, C., Jung, F., Lendlein, A. %D 2013 %J 17th Conference of the European Society for Clinical Hemorheology and Microcirculation, ESCHM 2013 %T Angiogenically stimulated intermediate monocytes maintain their proangiogenic and non-inflammatory phenotype in long time co-cultures with HUVEC %U %X %0 conference lecture (invited) %@ %A Neffe, A.T., Gebauer, T., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Tailoring the elastic properties and protein adsorption of gelatin-based networks by crosslinking with diisocyanates of differing reactivity and solubility in water %U %X %0 conference lecture %@ %A Lendlein, A. %D 2013 %J Method Workshop 2013 %T Introduction of Protein Adsorption %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2013 %J Shape Memory and Superelastic Technology Conference, SMST 2013 %T Memory-Effects of Polymers and their Relevance for Biomedical Applications %U %X %0 conference lecture %@ %A Wang, W., Kratz, K., Xu, X., Li, Z., Jung, F., Ma, N., Lendlein, A. %D 2013 %J 17th Conference of the European Society for Clinical Hemorheology and Microcirculation, ESCHM 2013 %T Interaction of human mesenchymal stem cells with soft hydrophobic poly(n-butyl acrylate) networks with elastic moduli comparable to arteries %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2013 %J 3rd HIPS Symposium on Pharmaceutical Science Devoted to Infection Research %T Degradable Elastomers for Medical and Pharmaceutical Applications %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2013 %J Innovationsmotor Medizintechnik, Technologie Tag Teltow 2013 %T Technologie und Medizin %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2013 %J European Polymer Federation 2013 %T Multifunctional Biomaterials %U %X %0 conference lecture (invited) %@ %A Behl, M., Lendlein, A. %D 2013 %J International Workshop on Biodegradable Polymers in Medicine %T Oligodepsipeptide- and Oligoester-based Copolymers %U %X %0 conference lecture %@ %A Neffe, A.T., Lendlein, A. %D 2013 %J Eroeffnung der Graduiertenschule MacroBio %T Biopolymer-based Biomaterials %U %X %0 conference lecture %@ %A Lendlein, A. %D 2013 %J 2013 MRS Spring Meeting and Exhibit %T Comparison of memory effects in multiblockcopolymers and covalent polymer networks %U %X %0 conference poster %@ %A Balk, M., Behl, M., Noechel, U., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Shape-Memory Hydrogels with Crystallizable Oligotetrahydrofurane Side Chains %U %X %0 conference lecture (invited) %@ %A Behl, M., Kratz, K., Lendlein, A. %D 2013 %J Soft Control - Switching Surface Properties with Stimulus Responsive Polymers at Interfaces %T Shape-Memory Polymers – From One Way Effects to Programmable Actuators %U %X %0 journal article %@ 1946-4274 %A Friess, F., Lendlein, A., Wischke, C. %D 2013 %J MRS Online Proceedings Library %P 173-178 %R doi:10.1557/opl.2013.815 %T Morphology of crosslinked poly(Epsilon-caprolactone) microparticles %U https://doi.org/10.1557/opl.2013.815 %X In order to explore the feasibility for preparing defined crosslinked particulate structures, oligo(ε-caprolactone) [oCL] derived microparticles (MPs) were crosslinked in non-molten, non-dissolved, i.e. solid state in aqueous suspension by applying a controlled regime with well-defined polymer network precursors either with or without photoinitiator. The MPs (diameter ∼ 40 μm) were prepared by an oil-in-water emulsion process from linear 2oCL or 4-arm star-shaped 4oCL with methacrylate end groups. Crosslinking was initiated by UV-laser irradiation (308 nm) at room temperature. Conversion of methacrylate was monitored by ATR-FTIR spectroscopy and crosslinking was confirmed by a lack of MP dissolution in dichloromethane. In a quantitative evaluation of swelling by dynamic light scattering, higher swelling ratios were detected for particles synthesized with photoinitiator. Wrinkled particle surfaces and distorted particle shapes were observed by light microscopy in the solvent-swollen state and by scanning electron microscopy after deswelling. This work indicated some limitations due to internal inhomogeneity of the MP, but particle crosslinking in solid state was generally possible and may be further improved by higher chain mobility during crosslinking. %0 journal article %@ 0032-3861 %A Ghobadi, E., Heuchel, M., Kratz, K., Lendlein, A. %D 2013 %J Polymer %N 16 %P 4204-4211 %R doi:10.1016/j.polymer.2013.05.064 %T Influence of the addition of water to amorphous switching domains on the simulated shape-memory properties of poly(l-lactide) %U https://doi.org/10.1016/j.polymer.2013.05.064 16 %X All simulated PLLA models showed high shape fixity ratio of Rf ≥ 84%. The shape-memory properties obtained at εm = 100% for the dry PLLA and the models containing 1 wt% water were almost identical with a shape recovery ratio in the first and second test cycle around Rr = 61%–64%. In contrast PLLA with 2 wt% water exhibited higher values of Rr = 76% during the first test cycle, but a lower Rr = 52% in the subsequent second cycle. Furthermore, increasing the applied εm resulted in a decrease of Rr from 82% to 42% for the dry PLLA, whereas PLLA with 2 wt% water did not show a dependence of Rr on εm. We anticipate that these observations can be attributed to differences in the initial structure of the various simulated PLLA models e.g. the different distribution of the free volume elements. %0 journal article %@ 0168-3659 %A Wischke, C., Schneider, C., Neffe, A.T., Lendlein, A. %D 2013 %J Journal of Controlled Release %N 1 %P e 22 %R doi:10.1016/j.jconrel.2013.08.052 %T Sustained release hydrogels by in situ polymerized polyalkylcyanoacrylate coating %U https://doi.org/10.1016/j.jconrel.2013.08.052 1 %X No abstract %0 conference object %@ %A Lendlein, A., Razzaq, M.Y., Kratz, K., Behl, M. %D 2013 %J Abstracts of Papers of the American Chemical Society, 245th National Spring Meeting of the American-Chemical-Society %P 164-PMSE %T Magnetically triggered memory-effects of active nanocomposites %U %X %0 journal article %@ 1022-1352 %A Ghobadi, E., Heuchel, M., Kratz, K., Lendlein, A. %D 2013 %J Macromolecular Chemistry and Physics %N 11 %P 1273-1283 %R doi:10.1002/macp.201200450 %T Simulating the Shape-Memory Behavior of Amorphous Switching Domains of Poly(L-lactide) by Molecular Dynamics %U https://doi.org/10.1002/macp.201200450 11 %X The thermally induced shape-memory effect of polymers is typically characterized by cyclic uniaxial thermomechanical tests. Here, a molecular-dynamics (MD) simulation approach of such a cyclic uniaxial thermomechanical test is presented for amorphous switching domains of poly(L-lactide) (PLLA). Uniaxial deformation of the constructed PLLA models is simulated with a Parinello–Rahman scheme, as well as a pragmatic geometrical approach. We are able to describe two subsequent test cycles using the presented simulation approach. The obtained simulated shape-memory properties in both test cycles are similar and independent of the applied deformation protocols. The simulated PLLA shows high shape fixity ratios (Rf ≥ 94%), but only a moderate shape recovery ratio is obtained (Rr ≥ 30%). Finally, the structural changes during the simulated test are characterized by analysis of the changes in the dihedral angle distributions. %0 conference poster %@ %A Saatchi, M., Behl, M., Lendlein, A. %D 2013 %J Advanced Functional Polymers for Medicine, 533th WE-Heraeus-Seminar %T Preparation and characterization of selective porous layer in multilayer structure %U %X %0 conference object %@ 1550-6703 %A Friess, F., Lendlein, A., Wischke, C. %D 2013 %J PMSE Preprints %P 3 %T Investigating side-reactions during UV-induced preparation of oligo(epsilon-caprolactone) based shape-memory polymer networks %U %X %0 conference lecture %@ %A Schulz, C., Ruesten-Lange, M.v., Krueger, A., Lendlein, A., Jung, F. %D 2013 %J 32. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Adherence and shear-resistancy of primary human endothelial cells on smooth poly(ether imide) films %U %X %0 conference lecture %@ %A Lendlein, A. %D 2013 %J Method Workshop 2013 %T Multifunctional Biomaterials for Medicine %U %X %0 conference lecture %@ %A Lendlein, A. %D 2013 %J PhD Workshop 2013 %T Biomaterials in Technology and Medicine, Institute of Biomaterial Science %U %X %0 conference poster %@ %A Krueger, A., Scharnagl, N., Trescher, K., Zierke, M., kratz, K., Behl, M., Jung, F., Lendlein, A. %D 2013 %J 32. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Behaviour of fibroblasts on water born acrylonitrile based copolymers with varying hydrophilicities %U %X %0 conference poster %@ %A Dietze, S., Braune, S., Krueger, A., Baudis, S., Behl, M., Kratz, K., Jung, F., Lendlein, A. %D 2013 %J 32. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Hemocompatibility of degradable poly[(rac-lactide)-co-glycolide] polymer network %U %X %0 journal article %@ 1552-4973 %A Trajkovski, B., Petersen, A., Perka, C., Scharnagl, N., Wischke, C., Wagermaier, W., Lendlein, A., Duda, G.N. %D 2013 %J Journal of Biomedical Materials Research B %N 6 %P 950-963 %R doi:10.1002/jbm.b.32900 %T Local drug delivery by personalized, intraoperative custom-made implant coating %U https://doi.org/10.1002/jbm.b.32900 6 %X Local administration of drugs can enhance regeneration, prevent infection, or treat postsurgical pain. If used in conjunction with implants, coating strategies should allow the choice of a drug or combination of drugs, their doses, localization, and release due to intraoperative considerations. Current coating technologies lack the ability for personalized medicine strategies. Here, we describe a new intraoperative strategy for drug delivery that allows a personalized approach as local drug delivery by implant coating. A polyvinylalcohol (PVA) patch provides rapid attachment to implant surfaces by cyanoacrylate (CA) adhesives. The CA polymerization was initiated by water uptake of the patch due to exposure to a humid environment. The coating strength depended on the type of the CA, the time of external pressing load and humidification, the properties of the patch and the implant surface. The CA adhesive penetrated and polymerized within the patch without impeding the bioactivity of the embedded molecules or strongly altering the protein release pattern after attachment to the implant surface. The use of CA in combination with the PVA patch proved to be noncytotoxic in vitro. This technology platform opens the possibility for personalized medicine to locally administer drugs due to intraoperative requirements. %0 conference lecture %@ %A Julich-Gruner, K.K., Roch, T., Ma, N., Neffe, A.T., Lendlein, A. %D 2013 %J 2013 MRS Spring Meeting and Exhibit, Symposium MM – Advanced Materials for Biological and Biomedical Applications %T Synthesis and biological evaluation of oligoethylene glycol materials functionalized with desaminotyrosine and desaminotyrosyltyrosine %U %X %0 journal article %@ 1946-4274 %A Julich-Gruner, K.K., Roch, T., Ma, N., Neffe, A.T., Lendlein, A. %D 2013 %J MRS Online Proceedings Library %P 9-14 %R doi:10.1557/opl.2013.831 %T Immunological investigations of oligoethylene glycols functionalized with desaminotyrosine and desaminotyrosyltyrosine %U https://doi.org/10.1557/opl.2013.831 %X Biomaterials require thorough in vitro testing before being applied in vivo. Unwanted contaminations of biomaterials but also their intrinsic properties can cause uncontrolled immune response leading to severe consequences for the patient. Therefore, immunological evaluation of materials for biomedical applications is mandatory before entering clinical application. In order to introduce physical netpoints, the aromatic compounds desaminotyrosine (DAT) and desaminotyrosyl-tyrosine (DATT) were successfully used to functionalize linear and star-shaped oligoethylene glycol (lOEG and sOEG) as previously described. The materials showed properties of surfactants and have potential to be used for solubilization of lipophilic drugs in water. Furthermore, the materials are susceptible for H2O2 degradation as determined by MALDI-ToF MS analyses. This is important for potential in vivo applications, as macrophages can release reactive oxygen species (ROS) under inflammatory conditions. As it is known that surfactant solutions of high concentration can lead to cell lysis, the effects of OEG-DAT(T) solutions on murine RAW macrophages were investigated. Even at highest OEG-DAT(T) concentration of 1000 µg·mL-1 the viability of the RAW cells was not significantly impaired. Additionally, the polymers were incubated with whole human blood and the production of inflammatory cytokines such as the tumor necrosis factor (TNF)-α and interleukin (IL)-6 was determined. Only at high concentrations, the OEG-DAT(T) solution induced low levels of TNF-α and IL-6, indicating that a mild inflammatory reaction could be expected when such high OEG-DAT(T) concentrations are applied in vivo. Similarly, the OEG-DAT(T) solution did not induce ROS in monocytes and neutrophils after incubation with whole human blood. Conclusively, the data presented here demonstrate that OEG-DAT(T) do not lead to a substantial activation of the innate immune mechanisms and could therefore be investigated for solubilizing pharmaceutical agents. %0 journal article %@ 0884-2914 %A Pehlivanova, V., Krasteva, V., Seifert, B., Luetzow, K., Tsoneva, I., Becker, T., Richau, K., Lendlein, A., Tzoneva, R. %D 2013 %J Journal of Materials Research %N 16 %P 2180-2186 %R doi:10.1557/jmr.2013.193 %T The role of alternating current electric field for cell adhesion on 2D and 3D biomimetic scaffolds based on polymer materials and adhesive proteins %U https://doi.org/10.1557/jmr.2013.193 16 %X Tissue engineering principles suggest the formation of 3D scaffolds based on polymer fibers and adhesive proteins. These scaffolds aim to mimic the native extracellular matrix and thus providing a favorable environment for cell attachment and proliferation. The application of an electric field (EF) can influence the quantity and the spatial orientation/conformation of adsorbed proteins, which could lead to changes in their functions. We study the influence of alternating current (AC) EF on the adsorption of fibronectin onto poly(etherimide) (PEI) electrospun fiber materials in 3D structures and subsequent cell adhesion. The results are compared with 2D PEI material and glass surface. 3D scaffolds adsorbed a lower amount of fibronectin than 2D film or glass. Application of AC EF with a frequency of 1 Hz decreased the adsorption of fibronectin. Cell adhesion on 3D materials was reduced compared with 2D film and glass. The application of EF with frequencies between 1 and 10 Hz improved cell adhesion on both 2D and 3D materials. %0 journal article %@ 0008-6215 %A Tripodo, G., Wischke, C., Neffe, A.T., Lendlein, A. %D 2013 %J Carbohydrate Research %P 59-63 %R doi:10.1016/j.carres.2013.08.018 %T Efficient synthesis of pure monotosylated beta-cyclodextrin and its dimers %U https://doi.org/10.1016/j.carres.2013.08.018 %X 6-O-Monotosyl-β-cyclodextrin (mono-Ts-βCD) is one of the most important intermediates in the production of substituted βCD. So far, performing the monotosylation reaction and, in particular, the purification steps was challenging, relied on toxic solvents, and resulted in long and expensive procedures at, importantly, low yields. Here, the reaction of cyclodextrin with p-toluenesulfonyl chloride in aqueous environment is described to obtain a highly pure mono-Ts-βCD, for which a single-step purification with a cation exchange resin was applied. With this synthetic route and purification, yields could be increased from typically <10–15% to 35%, and organic solvents could be avoided. As characterized by FTIR, mass spectrometry, elemental analysis, and NMR, mono-Ts-βCD was obtained with a molar purity of >98 mol %. From mono-Ts-βCD, β-cyclodextrin dimers linked by ethylenediamine (bis-Et-βCD) were successfully prepared (yield 93%, purity 96 mol %) in a one-step approach using an anion exchange resin to trap leaving groups that typically interfere in the reaction. This synthesis procedure with a direct collection of side-products may be a general strategy applicable for nucleophilic substitution of tosylated cyclodextrins. %0 journal article %@ 0939-6411 %A Wischke, C., Krueger, A., Roch, T., Pierce, B.F., Li, W., Jung, F., Lendlein, A. %D 2013 %J European Journal of Pharmaceutics and Biopharmaceutics %N 2 %P 288-296 %R doi:10.1016/j.ejpb.2013.01.025 %T Endothelial cell response to (co)polymer nanoparticles depending on the inflammatory environment and comonomer ratio %U https://doi.org/10.1016/j.ejpb.2013.01.025 2 %X Endothelial cells lining the lumen of blood vessels serve as a physiological barrier controlling nanoparticle movement from the vasculature into the tissue. For exploring the effect of polymer hydrophilicity on nanoparticle interactions with human umbilical vein endothelial cells (HUVECs) in vitro, a series of monomodal poly[acrylonitrile-co-(N-vinylpyrrolidone)] model nanoparticles with increasing hydrophilicity as related to their increasing content (0–30 mol.%) of N-vinylpyrrolidone (NVP) were synthesized by miniemulsion polymerization. Nanoparticles with a low NVP content were rapidly endocytized into all cells independent from the particle dose with toxic effects only observed at high particle concentrations, while only 10–30% of the cells incorporated particles with ⩾20 mol.% NVP. Since pathologies are often related to inflammation, an inflammatory HUVEC culture condition with IL-1β stimulation has been introduced and suggested to be widely applied for studying nanocarriers, since cellular uptake in this assay was clearly increased for NVP contents ⩾20 mol.%. Importantly, the secretion of functional biological mediators by HUVECs was not relevantly influenced by the nanoparticles for both homeostatic and inflammatory conditions. These findings may motivate concepts for nanocarriers specifically targeted to pathologic regions. Additionally, rapidly endocytized Rhodamin B loaded particles with low NVP content may be explored for cell labeling and tracking. %0 journal article %@ 1742-5247 %A Wischke, C., Behl, M., Lendlein, A. %D 2013 %J Expert Opinion on Drug Delivery %N 9 %P 1193-1205 %R doi:10.1517/17425247.2013.797406 %T Drug-releasing shape-memory polymers – The role of morphology, processing effects, and matrix degradation %U https://doi.org/10.1517/17425247.2013.797406 9 %X Expert opinion: The combination of SMPs with a drug-release functionality leads to multifunctional carriers that are an interesting technology for pharmaceutical sciences and can be further expanded by new materials such as thermoplastic SMPs or temperature-memory polymers. Experimental studies should include relevant molecules as (model) drugs and provide a thermomechanical characterization also in an aqueous environment, report on the potential effect of drug type and loading levels on the shape-memory functionality, and explore the potential correlation of polymer degradation and drug release. %0 journal article %@ 0168-3659 %A Wischke, C., Schneider, C., Neffe, A.T., Lendlein, A. %D 2013 %J Journal of Controlled Release %N 3 %P 321-328 %R doi:10.1016/j.jconrel.2013.02.013 %T Polyalkylcyanoacrylates as in situ formed diffusion barriers in multimaterial drug carriers %U https://doi.org/10.1016/j.jconrel.2013.02.013 3 %X Polymeric hydrogels typically release their drug payload rapidly due to their high water content and the diffusivity for drug molecules. This study proposes a multimaterial system to sustain the release by covering the hydrogel with a poly(alkyl-2-cyanoacrylate) [PACA]-based film, which should be formed by an in situ polymerization on the hydrogel surface initiated upon contact with water. A series of PACA-hydrogel hybrid systems with increasing PACA side chain hydrophobicity was prepared using physically crosslinked alginate films and hydrophilic diclofenac sodium as model hydrogel/drug system. Successful synthesis of PACA at the hydrogel surface was confirmed and the PACA layer was identified to be most homogeneous for poly(n-butyl-2-cyanoacrylate) on both the micro- and nanolevel. At the same time, the diclofenac release from the hybrid systems was substantially sustained from ~ 1 day for unmodified hydrogels up to > 14 days depending on the type of PACA employed as diffusion barrier. Overall, in situ polymerized PACA films on hydrogels may be widely applicable to various hydrogel matrices, different matrix sizes as well as more complex shaped hydrogel carriers. %0 conference object %@ %A Friess, F., Lendlein, A., Wischke, C. %D 2013 %J Abstracts of Papers of the American Chemical Society, 245th National Spring Meeting of the American-Chemical-Society %P 312-PMSE %T Investigating Side-reactions During UV-induced Preparation of oligo(E-caprolactone) Based Shape-memory Polymer Networks %U %X No abstract %0 conference lecture (invited) %@ %A Lendlein, A., Razzaq, M.Y., Kratz, K., Behl, M. %D 2013 %J 245th National Spring Meeting of the American-Chemical-Society %T Magnetically triggered memory-effects of active nanocomposites %U %X %0 journal article %@ 0378-5173 %A Heilmann, S., Kuechler, S., Wischke, C., Lendlein, A., Stein, C., Schaefer-Korting, M. %D 2013 %J International Journal of Pharmaceutics %N 1-2 %P 96-102 %R doi:10.1016/j.ijpharm.2013.01.027 %T A thermosensitive morphine-containing hydrogel for the treatment of large-scale skin wounds %U https://doi.org/10.1016/j.ijpharm.2013.01.027 1-2 %X The results of our in vitro study indicate that the thermosensitive poloxamer 407 25 wt.% hydrogel is an appropriate carrier system for the topical application of morphine with regard to sustained drug release and ongoing analgesia. %0 journal article %@ 0168-1656 %A Trescher, K., Roch, T., Cui, J., Kratz, K., Lendlein, A., Jung, F. %D 2013 %J Journal of Biotechnology %N 1-2 %P 58-64 %R doi:10.1016/j.jbiotec.2013.04.012 %T Test system for evaluating the influence of polymer properties on primary human keratinocytes and fibroblasts in mono- and coculture %U https://doi.org/10.1016/j.jbiotec.2013.04.012 1-2 %X Poly(n-butyl acrylate) networks (cPnBAs) as model biomaterials were used to demonstrate the applicability of our newly developed coculture screening system for differential cell growth. The apparent Young's modulus of the cPnBAs differentially regulated fibroblasts and keratinocytes. Particularly, cPnBA73 with an apparent Young's modulus of 930 ± 140 kPa measured in phosphate buffered saline (PBS) solution at ambient temperature seemed to have favoring properties for keratinocyte adhesion, while fibroblast adhesion was not affected. For keratinocytes the concentration of some pro-inflammatory cytokines was lower on cPnBA73 and a decreased deposition of collagen, elastin and fibronectin was observed in the coculture. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2013 %J Fachkonferenz Ingenieurwissenschaften %T Technologie und Medizin %U %X %0 conference lecture %@ %A Lendlein, A. %D 2013 %J Institutspraesentation beim Helmholtz-Junior-Meeting 2013 %T Welcome to HZG Campus Teltow %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2013 %J 2013 MRS Spring Meeting and Exhibit %T Translating processes on the molecular level to macroscopic functions in polymer networks %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2013 %J Seminar am Karlsruher Institut fuer Technologie %T Multifunctional Biomaterials %U %X %0 conference lecture %@ %A Lendlein, A. %D 2013 %J Kick-off Meeting Helmholtz-Graduiertenschule, Macromolecular Bioscience %T Biomaterials in Technology and Medicine %U %X %0 conference poster %@ %A Schmidt, C., Behl, M., Lendlein, A., Beuermann, S. %D 2013 %J 2013 MRS Spring Meeting and Exhibit %T Supercritical Carbon Dioxide as Reaction Medium for the Synthesis of the Biodegradable Polymer Polyglycolide %U %X %0 conference lecture %@ %A Behl, M., Razzaq, M., Lendlein, A. %D 2013 %J 2013 MRS Spring Meeting and Exhibit %T Nanocomposites of Magnetic Nanoparticles in Crystallizable Matrices as Platform Technology for Actively Moving Polymers %U %X %0 conference lecture %@ %A Roch, T., Schmidt, S., Kratz, K., Ma, N., Lendlein, A. %D 2013 %J 17th Conference of the European Society for Clinical Hemorheology and Microcirculation, ESCHM 2013 %T The influence of polymeric substrates differing in their chemical structure on survival, proliferation, and activation of primary human B cells %U %X %0 conference lecture %@ %A Schmidt, S., Roch, T., Kratz, K., Ma, N., Lendlein, A. %D 2013 %J 32. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Investigations of Cell Culture Inserts Engineered from Polystyrene and Poly(ether imide) for B Cell Cultivation %U %X %0 conference poster %@ %A Gebauer, T., Neffe, A.T., Lendlein, A. %D 2013 %J 28. Tag der Chemie %T Influence of diisocyanate reactivity and water solubility on the formation of gelatin-based networks in water %U %X %0 journal article %@ 1022-1360 %A Saatchi, M., Behl, M., Lendlein, A. %D 2013 %J Macromolecular Symposia %N 1 %P 33-39 %R doi:10.1002/masy.201300151 %T Manufacturing and Characterization of Controlled Foaming of Single Layers in Bilayer Constructs Differing in Pore Morphology %U https://doi.org/10.1002/masy.201300151 1 %X Bilayer porous constructs from degradable polymers are considered as scaffold materials with beneficial elastic properties for cell culture application in tissue engineering. Here, we explored whether such bilayer constructs, in which only one layer was porous while the other layer enhanced the compressive mechanical properties, could be created by specific foaming of one layer with supercritical carbon dioxide (scCO2). The bilayer constructs of a poly(L-lactide) (PLLA) and a poly(ϵ-caprolactone) (PCL) layer were prepared by sequential injection molding and subsequent specific foaming with scCO2. Foaming conditions of T = 45 °C and P = 100 bar resulted in the formation of a porous PCL layer and a non-porous PLLA layer. When the time intervals of the foaming process were increased the pore size was increased and the shape of the pores was changed from a circular to an unidirectional lamellar shape, which reduced the compressive elastic modulus of the porous PCL layer. Furthermore, the foaming process increased the adhesion force between the PLLA and PCL layers, which was attributed to a higher degree of diffusion of molten PCL into the PLLA layer. In summary, it was demonstrated that scCO2 foaming is a suitable method for the creation of layered scaffolds with only one foamed layer, in which the compressive elastic modulus and pore morphology of single porous layers can be controlled by the time interval of scCO2 process. %0 conference lecture %@ %A Ekinci, D., Sisson, A.L., Lendlein, A. %D 2013 %J 2013 MRS Spring Meeting and Exhibit, Symposium NN: Multifunctional Biomaterials %T Poly(glycidyl ether) Networks as a Versatile Platform for Potential Biomaterial Applications %U %X %0 journal article %@ 1386-0291 %A König, J., Kohl, B., Kratz, K., Jung, F., Lendlein, A., Ertel, W., Schulze-Tanzil, G. %D 2013 %J Clinical Hemorheology and Microcirculation %N 4 %P 523-533 %R doi:10.3233/CH-131788 %T Effect of polystyrene and polyether imide cell culture inserts with different roughness on chondrocyte metabolic activity and gene expression profiles of aggrecan and collagen %U https://doi.org/10.3233/CH-131788 4 %X In vitro cultured autologous chondrocytes can be used for implantation to support cartilage repair. For this purpose, a very small number of autologous cells harvested from a biopsy have to be expanded in monolayer culture. Commercially available polymer surfaces lead to chondrocyte dedifferentiation. Hence, the demanding need for optimized polymers and surface topologies supporting chondrocytes' differentiated phenotypes in vitro arises. In this study we explored the effect of tailored cell culture plate inserts prepared from polystyrene (PS) and polyether imide (PEI) exhibiting three different roughness levels (R0, RI, RII) on chondrocyte morphology, metabolism and gene expression profile. As a control, commercially available tissue culture plastic (TCP) dishes were included. Primary porcine articular chondrocytes were seeded on tailored PS and PEI inserts with three different roughness levels. The metabolic activity of the chondrocytes was determined after 24 hours using alamar blue assay. Chondrocyte gene expression profiles (aggrecan, type I and type II collagen) were monitored after 48 hours using Real Time Detection (RTD)-PCR. Chondrocytes cultured on PS and PEI surfaces formed cell clusters after 24 and 48 hours, which was not observed on TCP. The metabolic activity of chondrocytes cultured on PS was lower than of chondrocytes cultured on PEI, but also lower than on TCP. Gene expression analyses revealed an elevated expression of cartilage-specific aggrecan and an impaired expression of both collagen types by chondrocytes on PS and PEI compared with TCP. In summary, PEI is a biocompatible biomaterial suitable for chondrocyte culturing, which can be further chemically functionalized for generating specific surface interactions or covalent binding of biomolecules. %0 journal article %@ 1946-4274 %A Ekinci, D., Sisson, A.L., Lendlein, A. %D 2013 %J MRS Online Proceedings Library %P 79-84 %R doi:10.1557/opl.2013.962 %T Quantification of Protein Adsorption on Polyglycerol-based Polymer Network Films %U https://doi.org/10.1557/opl.2013.962 %X Neutral, hydrophilic, polymer-based architectures are widely investigated for a wide range of biomedical applications from drug-conjugates to delivery systems and scaffolds for regenerative therapies. In most cases, it is crucial that biomaterials provide a blank, inert background in order to hinder unspecific cell-material interactions so that protein mediated biological events leading to foreign body reactions are prevented. Hydrophilic polyglycerol-based polymer network films are a recently developed class of amorphous macroscopic materials, which offer great versatility in design and control of resultant properties. In this study, protein adsorption on polyglycerol-based polymer network films is investigated by using Micro BCA protein assay for three types of proteins having critical roles in the human body, and various copolymer networks with differing sidechains and crosslink densities. %0 journal article %@ 1022-1360 %A Racheva, M., Julich-Gruner, K.K., Nöchel, U., Neffe, A.T., Wischke, C., Lendlein, A. %D 2013 %J Macromolecular Symposia %N 1 %P 24-32 %R doi:10.1002/masy.201300112 %T Influence of Drying Procedures on Network Formation and Properties of Hydrogels from Functionalized Gelatin %U https://doi.org/10.1002/masy.201300112 1 %X Side chain functionalization of gelatin with tyrosine-derived moieties, desaminotyrosine (DAT) or desaminotyrosyl tyrosine (DATT), has been reported to lead to physical networks stabilized by aromatic interactions and hydrogen bonds, while the inherent ability of gelatin chains to organize in helices is suppressed. Here, the treatment of DAT and DATT gelatin films at defined temperatures (drying at 5 °C, freeze-drying, and freeze-thawing) were explored for the potential to additionally stabilize the hydrogels by increasing the content of helical domains as additional physical netpoints. The influence of the drying procedures on the hydrogel properties such as network morphology and mechanical properties were analyzed by WAXS, swelling, and rheological measurements. The triple helix content had a stabilizing effect on gelatin-based hydrogels at temperatures below the helix-to-coil transition. However, this effect was less pronounced at physiological conditions above the transition temperature, resulting in rapid dissolution of the physical gelatin networks. %0 journal article %@ 0168-3659 %A Wischke, C., Neffe, A.T., Hanh, B.D., Kreiner, C.F., Sternberg, K., Stachs, O., Guthoff, R.F., Lendlein, A. %D 2013 %J Journal of Controlled Release %N 3 %P 1002-1010 %R doi:10.1016/j.jconrel.2013.10.021 %T A multifunctional bilayered microstent as glaucoma drainage device %U https://doi.org/10.1016/j.jconrel.2013.10.021 3 %X Commercial non-degradable glaucoma implants are often associated with undesired hypotony, fibrosis, long term failure, and damage of adjacent tissues, which may be overcome by a multifunctional polymeric microstent for suprachoroidal drainage. This study reports the design and fabrication of such devices with tailorable internal diameters (50–300 μm) by solvent-free, continuous hot melt extrusion from blends of poly[(ε-caprolactone)-co-glycolide] and poly(ε-caprolactone) [PCL]. A spatially directed release was supported by bilayered microstents with an internal drug-free PCL layer, and a quantitative description of release kinetics with diclofenac sodium as model drug was provided. Furthermore, the slow degradation pattern (> 1 year) was analyzed and potential effects of 1–5 wt.% drug loading on material properties were excluded. Translational aspects including sterilization by γ-irradiation on dry ice, in vitro biocompatibility, and in vivo implantation were addressed. The promising results support further functional analysis of long-term in vivo performance and suppression of disadvantageous capsule formation. %0 journal article %@ 1743-4440 %A Neffe, A.T., Wischke, C., Racheva, M., Lendlein, A. %D 2013 %J Expert Review of Medical Devices %N 6 %P 813-833 %R doi:10.1586/17434440.2013.839209 %T Progress in biopolymer-based biomaterials and their application in controlled drug delivery %U https://doi.org/10.1586/17434440.2013.839209 6 %X Biopolymer-based materials are based on re-growing resources and are attractive for biomedical applications, as they can inherently combine degradability in vivo, can offer sites of adhesion for cells and proteins, often show good biocompatibility and may additionally be used to release embedded bioactive molecules. However, their selection and efficient use for specific applications require an understanding of molecular principles and relationships between the molecular and macroscopic level to establish distinct properties and functions. Here, synthetic routes are described, which allow tailoring properties and functions of biopolymer-based materials. The biological evaluation of such materials is discussed, with a special emphasis on their application in controlled release systems such as hydrogels and particulate carriers. %0 conference lecture %@ %A Ekinci, D., Sisson, A.L., Lendlein, A. %D 2013 %J 2013 MRS Spring Meeting and Exhibit, Symposium MM – Advanced Materials for Biological and Biomedical Applications %T Quantification of Protein Adsorption on Polyglycerol-based Polymer Network Films %U %X %0 book part %@ %A Sisson, A., Lendlein, A. %D 2013 %J Biomaterials for Stem Cell Therapy %P 3-36 %R doi:10.1201/b14584 %T Synthetic Polymer-Network Based Materials in Stem Cell Research %U https://doi.org/10.1201/b14584 %X Owing to the pioneering research in the early 1990s popularizing the use of degradable polymers in aspects of tissue engineering and regenerative medicine (Langer and Vacanti 1993), polymeric networks have since received fervent interest for a range of biomedical applications (Hubbell 1995, Varghese and Elisseeff 2006). The central paradigm has developed from a realization that synthetic matrices can in many ways mimic natural extracellular matrices, which are essential to regulate cell behaviour in biological systems (Shastri and Lendlein 2009, 2010). Numerous parameters such as cellular attachment, structural and rheological parameters, biodegradability, and solute diffusion, can be rationally controlled during synthesis, leading to potentially very powerful tools for regulating biological processes. In biomaterial research polymeric networks are used for various applications such as vehicles for cell delivery, scaffolds for cellular adhesion and harvesting, and as sources of soluble or immobilized Helmholtz Zentrum Geesthacht, Center for Biomaterial Development and Berlin Brandenburg Centre for Regenerative Therapies, D-14513 Teltow, Germany. aEmail: Andreas.Lendlein@hzg.de Corresponding author growth factors to promote cell differentiation (Chai and Leong 2007, Dawson et al. 2008, Hwang et al. 2008). It has been realized that stem cells can be manipulated in contact with materials other than native tissues, and as such polymeric biomaterials can often serve as a “blank slate” for incorporating functionalities without interference from inherent interactions from naturally occurring biopolymers. %0 journal article %@ 1386-0291 %A Hashimdeen, S.S., Römhild, A., Schmueck, M., Kratz, K., Lendlein, A., Kurtz, A., Reinke, P. %D 2013 %J Clinical Hemorheology and Microcirculation %N 4 %P 501-512 %R doi:10.3233/CH-131786 %T Culture surface influence on T-cell phenotype and function %U https://doi.org/10.3233/CH-131786 4 %X When dealing with T lymphocyte culture there is currently very less information available about the interaction between T-cells and the culture system. In this study we look at the influence of the culture chamber on T-cell proliferation in two main aspects of the culture system, namely: culture chamber material and geometry. The study was carried out using unique polymeric closed cell culture inserts, which were processed via injection moulding from polystyrene (PS), polycarbonate (PC), polyetherurethane (PEU), polystyrene-co-acrylonitrile (PSAN) and polyetherimide (PEI). Furthermore culture chamber geometry was studied using commercially available 24, 12 and 6-well plates prepared from tissue culture plastic (TCP). For T lymphocyte stimulation two methods were used involving either EBV peptide pools or MACS iBead particles depending on the experiment performed. Culture was done with 1645 RPMI medium supplemented with foetal calf serum, penicillin, streptomycin and rhIL-2. We found four materials out of five we tested (PS, PC, PSAN and PEI) exhibited similar fold expansions with minimal influence on proportions of CD4 and CD8, while PEU had a negative influence on T cell growth along with adversely affected CD4/CD8 proportions. Changes in the geometry of TCP had no effect on T cell growth or maturation rather the size of geometry seems to have more influence on proliferation. T-cells appear to prefer smaller geometries during initial stages of culture while towards the end of the culture size becomes less significant to cell proliferation. The parameters tested in this study have significant influences on T-cell growth and are necessary to consider when designing and constructing expansion systems for antigen specific T lymphocytes. This is important when culturing T-cells for immunotherapeutic applications where antigen specificity, T-cell maturation and function should remain unaffected during culture. %0 editorial %@ 1022-1360 %A Lendlein, A., Neffe, A.T. %D 2013 %J Macromolecular Symposia %N 1 %P 8-9 %R doi:10.1002/masy.201370041 %T Preface: Advanced Functional Polymers in Medicine %U https://doi.org/10.1002/masy.201370041 1 %X This volume of Macromolecular Symposia is the conference proceeding volume from the 533th WE-Heraeus Seminar “Advanced Functional Polymers for Medicine” held in Bad Honnef, Germany, from May 27 to May 29, 2013. The meeting was organized by Andreas Lendlein and Axel T. Neffe as the third conference in the annual Advanced Functional Polymers for Medicine conference series %0 conference lecture (invited) %@ %A Behl, M., Kratz, K., Lendlein, A. %D 2013 %J International Workshop on Biodegradable Polymers in Medicine %T Shape-Memory Polymers %U %X %0 conference poster %@ %A Roch, T., Behl, M., Zierke, M., Pierce, B.F., Weigel, T., Ma, N., Kratz, K., Lendlein, A. %D 2013 %J 2013 MRS Spring Meeting and Exhibit, Symposium NN – Multifunctional Biomaterials %T The influence of the co-monomer ratio of poly[acrylonitrile-co-(N-vinylpyrrolidone)]s on primary human monocyte-derived dendritic cells %U %X %0 lecture %@ %A Neffe, A., Lendlein, A. %D 2013 %J %T Biopolymers; Master of Polymer Science - Advanced Topics %U %X %0 conference poster %@ %A Roch, T., Ma, N., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Strategies for the immunological evaluation of polymeric biomaterials %U %X %0 journal article %@ 1022-1352 %A Schroeter, M., Behl, M., Kaiser, C., Lendlein, A. %D 2013 %J Macromolecular Chemistry and Physics %N 11 %P 1215-1224 %R doi:10.1002/macp.201300059 %T Synthesis and Properties of Poly(p-phenylene ethynylene)s with Oxidation- and Reduction-Sensitive Moieties %U https://doi.org/10.1002/macp.201300059 11 %X The synthesis of redox-sensitive poly(p-phenylene ethynylene)s (rsPPEs) bearing protected quinones in their backbone by the Sonogashira coupling reaction is described. The rsPPEs show excellent solubility in toluene, tetrahydrofurane, and chloroform. Cleavage of the protection group of the incorporated quinone moieties enables main-chain conductive polymers having redox-sensitive properties to be produced. These redox-sensitive switches can be reduced and oxidized in solution, as well as in the solid state, accompanied by a change of the photoluminescence values. The processes occurring during oxidation and reduction are analyzed by UV–vis and photoluminescence spectroscopy and lead to a decrease of intensity of 80% during oxidation. Such multifunctional polymers may be useful for redox-potential changing stimuli in biological systems. %0 conference lecture %@ %A Razzaq, M., Behl, M., Lendlein, A. %D 2013 %J Helmholtz Graduate School for Macromolecular Bioscience, Summer School 2013 %T Multifunctional Hybrid Nanocomposites With Magnetically Controlled Reversible Shape-Memory Effect %U %X %0 conference lecture (invited) %@ %A Behl, M., Lendlein, A. %D 2013 %J Symposium in Honor of the 60th Birthday of Prof. Rudolf Zentel %T From Dual-Shape Polymers to Temperature-Memory Polymer Actuators %U %X %0 journal article %@ 1386-0291 %A Rüder, C., Sauter, T., Kratz, K., Haase, T., Peter, J., Jung, F., Lendlein, A., Zohlnhöfer, D. %D 2013 %J Clinical Hemorheology and Microcirculation %N 4 %P 513-522 %R doi:10.3233/CH-131787 %T Influence of fibre diameter and orientation of electrospun copolyetheresterurethanes on smooth muscle and endothelial cell behaviour %U https://doi.org/10.3233/CH-131787 4 %X Polymers exhibiting cell-selective effects represent an extensive research field with high relevance for biomedical applications e.g. in the cardiovascular field supporting re-endothelialization while suppressing smooth muscle cell overgrowth. Such an endothelial cell-selective effect could be recently demonstrated for a copolyetheresterurethane (PDC) containing biodegradable poly(p-dioxanone) and poly(ε-caprolactone) segments, which selectively enhanced the adhesion of human umbilical vein endothelial cells (HUVEC) while suppressing the attachment of smooth muscle cells (SMC). In this study we investigated the influence of the fibre orientation (random and aligned) and fibre diameter (2 μm and 500 nm) of electrospun PDC scaffolds on the adhesion, proliferation and apoptosis of HUVEC and SMC. Adhesion, viability and proliferation of HUVEC was diminished when the fibre diameter was reduced to a submicron scale, while the orientation of the microfibres did only slightly influence the cellular behaviour. In contrast, a submicron fibre diameter improved SMC viability. In conclusion, PDC scaffolds with micron-sized single fibres could be promising candidate materials for cell-selective stent coatings. %0 book part %@ %A Schroeter, M., Wildemann, B., Lendlein, A. %D 2013 %J Regenerative Medicine : From Protocol to Patient %P 529-556 %R doi:10.1007/978-94-007-5690-8_21 %T Biodegradable Materials %U https://doi.org/10.1007/978-94-007-5690-8_21 %X This chapter gives an overview about polymeric materials established in clinical use such as polyesters, polyurethanes, polyanhydrides, or carbohydrates. It describes further their synthesis and exemplary applications such as surgical sutures. Finally the importance of a continuing development of novel materials for future applications is pointed out, since the number of potential applications in the medical field is expanding rapidly. %0 journal article %@ 1386-0291 %A Roch, T., Kratz, K., Ma, N., Jung, F., Lendlein, A. %D 2013 %J Clinical Hemorheology and Microcirculation %N 1 %P 157-168 %R doi:10.3233/CH-131699 %T The influence of polystyrene and poly(ether imide) inserts with different roughness, on the activation of dendritic cells %U https://doi.org/10.3233/CH-131699 1 %X Dendritic cells (DC) have a pivotal role during inflammation. DC efficiently present antigens to T cells and shape the subsequent immune response by the secretion of pro- or anti-inflammatory cytokines and by the expression of co-stimulatory molecules. They respond to “danger signals” such as microbial products or fragments from necrotic cells or tissues, but were also described to be reactive towards biomaterials. However, how mechanical and physical properties of the subjacent substrate influences the DC activation is currently poorly understood. In this study micro patterned inserts prepared from polystyrene (PS) as well as from poly (ether imide) (PEI) with three different roughness levels of i) Rq = 0.29 μm (PS) and 0.23 μm (PEI); ii) Rq = 3.47 μm (PS) and 3.92 μm (PEI); and iii) Rq = 22.16 μm (PS) and 22.65 μm (PEI) were analyzed for their capacity to influence the activation of human monocytes derived DC. Since the DC were directly cultured in the inserts, the effects of the testing material alone could be investigated and influences from additional culture dish material could be excluded. The viability, the expression of the DC activation markers, and their cytokine/chemokine secretion were determined after the incubation with the different inserts in vitro. Both the PS and the PEI inserts did not influence the survival of the DC and their expression of co-stimulatory molecules. The expression of inflammatory cytokines was not altered by the PEI and PS inserts. However, the secretion of chemokines such as CCL2, CCL3, and CCL4 was influenced by the different roughness levels, indicating that material roughness has the capacity to modulate the DC phenotype. The data presented here will help to understand the interaction of DC with structured polymer surfaces. Biomaterial-induced immuno-modulatory effects mediated by DC may promote tissue regeneration or could potentially reduce inflammation caused by the implant material. %0 journal article %@ 1946-4274 %A Wang, L., Nöchel, U., Behl, M., Kratz, K., Lendlein, A. %D 2013 %J MRS Online Proceedings Library %P 123-128 %R doi:10.1557/opl.2013.799 %T Comparison of memory effects in multiblock copolymers and covalently crosslinked multiphase polymer networks composed of the same types of oligoester segments and urethane linker %U https://doi.org/10.1557/opl.2013.799 %X A pronounced temperature-memory effect was achieved for thermoplastic as well as crosslinked copolyesterurethanes. Hereby, the switching temperatureTsw could be adjusted via the variation of the applied deformation temperatureTdeform in the range from 32 °C to 53 °C for MBC and in the range from 29 °C to 78 °C for multiphase polymer networks. %0 journal article %@ 0177-9516 %A Duvinage, B., Harmsen, D., Lendlein, A., Schroeter, M. %D 2013 %J Praxis der Naturwissenschaften - Chemie in der Schule %N 8 %P 41-48 %T Von Mulchfolien bis zu Nahtmaterialien - Biologisch abbaubare Polymere %U 8 %X Am Beispiel von Mulchfolien und Nahtmaterialien in der Medizin wird die Verwendung von biologisch abbaubaren Polymeren im Alltag beschrieben und ein erprobtes Modellexperiment zum hydrolytischen Abbau von Nahtmaterialien vorgestellt. %0 conference lecture %@ %A Behl, M., Lendlein, A. %D 2013 %J Helmholtz Graduate School for Macromolecular Bioscience Summer School 2013 %T Welcome to HZG Campus Teltow, Institute for Biomaterial Science %U %X %0 conference lecture %@ %A Wischke, C., Roch, T., Merino, M., Krueger, A., Li, W., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Exploring mechanisms of material-mediated nanoparticle uptake by endothelial cells %U %X %0 journal article %@ 1946-4274 %A Neffe, A.T., Gebauer, T., Lendlein, A. %D 2013 %J MRS Online Proceedings Library %P 3-8 %R doi:10.1557/opl.2013.837 %T Tailoring of Mechanical Properties of Diisocyanate Crosslinked Gelatin-Based Hydrogels %U https://doi.org/10.1557/opl.2013.837 %X Polymer network formation is an important tool for tailoring mechanical properties of polymeric materials. One option to synthesize a network is the addition of bivalent crosslinkers reacting with functional groups present in a polymer. In case of polymer network syntheses based on biopolymers, performing such a crosslinking reaction in water is sometimes necessary in view of the solubility of the biopolymer, such as gelatin, and can be beneficial to avoid potential contamination of the formed material with organic solvents in view of applications in biomedicine. In the case of applying diisocyanates for the crosslinking in water, it is necessary to show that the low molecular weight bifunctional crosslinker has fully reacted, while tailoring of the mechanical properties of the resulting hydrogels is possible despite the complex reaction mechanism. Here, the formation of gelatin-based hydrogel networks with the diisocyanates 2, 4-toluene diisocyanate, 1, 4-butane diisocyanate, and isophorone diisocyanate is presented. It is shown that extensive washing of materials is required to ensure full conversion of the diisocyanates. The use of different diisocyanates gives hydrogels covering a large range of Young’s moduli (12-450 kPa). The elongations at break (up to 83%) as well as the maximum tensile strengths (up to 410 kPa) of the hydrogels described here are much higher than for lysine diisocyanate ethyl ester crosslinked gelatin reported before. Rheological investigations suggest that the network formation in some cases is due to physical interactions and entanglements rather than covalent crosslink formation. %0 journal article %@ 1946-4274 %A Schmidt, S., Roch, T., Mathew, S., Ma, N., Wischke, C., Lendlein, A. %D 2013 %J MRS Online Proceedings Library %P 179-184 %R doi:10.1557/opl.2013.816 %T Correlating the Uptake and Dendritic Cell Activation by MDP-loaded Microparticles %U https://doi.org/10.1557/opl.2013.816 %X Polymer-based, degradable microparticles (MP) are attractive delivery vehicles for vaccines as the polymer properties can be specifically tailored and the carrier can be loaded with adjuvant. For all newly developed carrier systems it is important to analyze cellular uptake efficiency and the specific effects mediated by the encapsulated agent when phagocytosed by the cells, which is barely reported so far. By the encapsulation of N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) labeled with fluoresceinisothiocyanat (FITC) in poly[(rac-lactide)-co-glycolide] (PLGA) MP, the MP was fluorescent and used to visualize the phagocytic uptake. Since encapsulated MDP can activate dendritic cells (DC) via the cytosolic nucleotide-binding oligomerization domain receptors (NOD), it can be investigated whether only cells that have phagocytosed the MP are activated or whether bystander effects occur, resulting in activation of cells, which did not take up MDP-FITC loaded MP. Here, it is demonstrated that increasing MP concentrations in the culture medium had no impact on the viability of DC and that the MP uptake efficiency was dose dependent. Interestingly, it could be shown by the CD86 expression, that only DC, which had engulfed MP, were significantly stronger activated than DC, which had not phagocytosed MDP-FITC loaded MP. On the one hand these results indicate that sufficient amounts of MDP were released from the PLGA carriers into the cytosol of the DC. On the other hand, based on the correlation of uptake and activation on the single cell level, minimal MP induced bystander effects may be expected forin vivo applications. %0 journal article %@ 1946-4274 %A Gebauer, T., Neffe, A.T., Lendlein, A. %D 2013 %J MRS Online Proceedings Library %P 15-20 %R doi:10.1557/opl.2013.839 %T Influence of diisocyanate reactivity and water solubility on the formation and the mechanical properties of gelatin-based networks in water %U https://doi.org/10.1557/opl.2013.839 %X Gelatin can be covalently crosslinked in aqueous solution by application of diisocyanates like L-lysine diisocyanate ethyl ester in order to form hydrogels. Reaction of isocyanate groups with water is however a limiting factor in hydrogel network formation and can strongly influence the outcome of the crosslinking process. Here, diisocyanates with different water solubility and reactivity were applied for the formation of gelatin-based hydrogel networks and the mechanical properties of the hydrogels were investigated to gain a better understanding of starting material/ hydrogel property relations. L-Lysin diisocyanate ethyl ester (LDI), 2, 4-toluene diisocyanate (TDI), 1, 4-butane diisocyanate (BDI), and isophorone diisocyanate (IPDI) were selected, having different solubility in water ranging from 10-4 to 10-2 mol·L-1. BDI and LDI were estimated to have average reactive isocyanates groups, whereas TDI is highly reactive and IPDI has low reactivity. Formed hydrogels showed different morphologies and were partially very inhomogeneous. Gelation time (1 to 50 minutes), water uptake (300 to 900 wt.-%), and mechanical properties determined by tensile tests (E-moduli 35 to 370 kPa) and rheology (Shear moduli 4.5 to 19.5 kPa) showed that high water solubility as well as high reactivity leads to the formation of poorly crosslinked or inhomogeneous materials. Nevertheless, diisocyanates with lower solubility in water and low reactivity are able to form stable, homogeneous hydrogel networks with gelatin in water. %0 journal article %@ 1946-4274 %A Roch, T., Behl, M., Zierke, M., Pierce, B.F., Kratz, K., Weigel, T., Ma, N., Lendlein, A. %D 2013 %J MRS Online Proceedings Library %P 21-26 %R doi:10.1557/opl.2013.830 %T The influence of the co-monomer ratio of poly[acrylonitrile-co-(N-vinylpyrrolidone)]s on primary human monocyte-derived dendritic cells %U https://doi.org/10.1557/opl.2013.830 %X A major goal in the field of regenerative medicine is to improve our understanding of how biomaterial properties affect cells of the immune system. Systematic variation of defined chemical properties could help to understand which factors determine and modulate cellular responses. A series of copolymers poly[acrylonitrile-co-(N-vinylpyrrolidone)]s (P(AN-co-NVP)) served as model system, in which increasing hydrophilicity was adjusted by increasing the content related to the NVP based repeating units (nNVP) (0, 4.6, 11.8, 22.3, and 29.4 mol%). The influence of increasing nNVP contents on cellular response of human primary monocyte derived dendritic cells (DC), which play a key role in the initiation of immune responses, was investigated. It was shown using the LAL-Test as well as a macrophage-based assay, that the materials were free of endotoxins and other microbial contaminations, which could otherwise bias the readout of the DC experiments. The increasing nNVP content led to a slightly increased cell death of DC, whereas the activation status of DC was not systematically altered by the different P(AN-co-NVP)s as demonstrated by the expression of co-stimulatory molecule and cytokine secretion. Similarly, under inflammatory conditions mimicked by the addition of lipopolysaccharides (LPS), neither the expression of co-stimulatory molecules nor the release of cytokines was influenced by the different copolymers. Conclusively, our data showed that this class of copolymers does not substantially influence the viability and the activation status of DC. %0 journal article %@ 1946-4274 %A Landsberger, P., Boenke, V., Gorbushina, A.A., Rodenacker, K., Pierce, B.F., Kratz, K., Lendlein, A. %D 2013 %J MRS Online Proceedings Library %P 85-90 %R doi:10.1557/opl.2013.832 %T Bacterial attachment on poly[acrylonitrile-co-(2-methyl-2-propene-1-sulfonic acid)] surfaces %U https://doi.org/10.1557/opl.2013.832 %X We found a reduced colonized area ofE. coli for NaMAS containing copolymers in comparison to pure PAN materials, whereby the bacterial colonization was similar for copolymers with different nNaMAS amounts. A different adhesion behavior was obtained for the second tested organismB. subtilis, where the implementation of negative charges into PAN did not change the overall adhesion pattern. Furthermore, it was observed thatB. subtilis adhesion was significantly increased on copolymer samples that exhibited a more irregular surface roughness. %0 journal article %@ 1946-4274 %A Behl, M., Razzaq, M.Y., Lendlein, A. %D 2013 %J MRS Online Proceedings Library %P 129-134 %R doi:10.1557/opl.2013.1060 %T Tailoring the recovery force in magnetic shape-memory nanocomposites %U https://doi.org/10.1557/opl.2013.1060 %X Here, we explored the adjustability of the recovery force as an important structural function in magnetic shape-memory nanocomposites (mSMC) by variation of the programing temperature (Tprog) and nanoparticle weight content. The nanocomposites were prepared by coextrusion of silica coated magnetite nanoparticles (mNP) with an amorphous polyether urethane (PEU) matrix. In tensile tests in whichTprog was varied between 25 and 70 °C and the particle content from 0 to 10 wt% it was found that the Young’s moduli (E) decreased with temperature and particle content. Cyclic, thermomechanical experiments with a recovery module under strain-control conditions were performed to monitor the effect of mNP andTprog on the recovery force of the composites. During the strain-control recovery the maximum stress (σm, r) at a characteristic temperature (Tσ, max) was recorded. By increasing the mNP content from 0 to 10 wt% in composites, σm, r of 1.9 MPa was decreased to 1.25 MPa at aTprog = 25 °C. A similar decrease inσm, r for nanocomposites with different mNP content could be observed whenTprog was increased from 25 °C to 70 °C. It can be concluded that the lower the deformation temperature and the particle content the higher is the recovery force. %0 conference lecture %@ %A Rijckaert, B., Neffe, A.T., Roch, T., Gebauer, T., Pierce, B.F., Goers, J., Smink, J.J., Gossen, M., Lendlein, A., Leutz, A. %D 2013 %J 12th International Polymers for Advanced Technologies Conference, PAT 2013 %T A High Content Screening Assay for Evaluation of Biomaterial-Mediated Cell Fusion Processes %U %X %0 journal article %@ 0935-9648 %A Behl, M., Kratz, K., Zotzmann, J., Nöchel, U., Lendlein, A. %D 2013 %J Advanced Materials %N 32 %P 4466-4469 %R doi:10.1002/adma.201300880 %T Reversible Bidirectional Shape-Memory Polymers %U https://doi.org/10.1002/adma.201300880 32 %X Free-standing copolymer network samples with two types of crystallizable domains are capable of a fully reversible bidirectional shape-memory effect. One set of crystallizable domains determines the shape-shifting geometry while the other provides the thermally controlled actuation capability. %0 journal article %@ 0935-9648 %A Razzaq, M.Y., Behl, M., Kratz, K., Lendlein, A. %D 2013 %J Advanced Materials %N 38 %P 5514-5518 %R doi:10.1002/adma.201301521 %T Triple-Shape Effect in Polymer-Based Composites by Cleverly Matching Geometry of Active Component with Heating Method %U https://doi.org/10.1002/adma.201301521 38 %X A triple-shape effect is created for a segmented device consisting of an active component encapsulated in a highly flexible polymer network. Segments with the same composition but different interface areas can be recovered independently either at specific field strengths (Hsw) during inductive heating, at a specific time during environmentally heating, or at different airflow during inductive heating at constant H. Herein the type of heating method regulates the sequence order. %0 journal article %@ 0935-9648 %A Razzaq, M.Y., Behl, M., Kratz, K., Lendlein, A. %D 2013 %J Advanced Materials %N 40 %P 5730-5733 %R doi:10.1002/adma.201302485 %T Multifunctional Hybrid Nanocomposites with Magnetically Controlled Reversible Shape–Memory Effect %U https://doi.org/10.1002/adma.201302485 40 %X Magneto-sensitivity and a thermo-sensitive reversible shape–memory effect have been successfully integrated into a hybrid nanocomposite, resulting in a magnetically controlled actuator. The complex requirements for gaining this multifunctionality are fulfilled by combining netpoints on the molecular and nano level in a polyesterurethane network prepared from hydroxyl group decorated magnetic nanoparticles, crystallizable star-shaped poly(ω-pentadecalactone) precursors, and a diisocyanate. %0 journal article %@ 0027-8424 %A Behl, M., Kratz, K., Noechel, U., Sauter, T., Lendlein, A. %D 2013 %J Proceedings of the National Academy of Sciences of the United States of America: PNAS %N 31 %P 12555-12559 %R doi:10.1073/pnas.1301895110 %T Temperature-memory polymer actuators %U https://doi.org/10.1073/pnas.1301895110 31 %X Reading out the temperature-memory of polymers, which is their ability to remember the temperature where they were deformed recently, is thus far unavoidably linked to erasing this memory effect. Here temperature-memory polymer actuators (TMPAs) based on cross-linked copolymer networks exhibiting a broad melting temperature range (ΔTm) are presented, which are capable of a long-term temperature-memory enabling more than 250 cyclic thermally controlled actuations with almost constant performance. The characteristic actuation temperatures Tacts of TMPAs can be adjusted by a purely physical process, guiding a directed crystallization in a temperature range of up to 40 °C by variation of the parameter Tsep in a nearly linear correlation. The temperature Tsep divides ΔTm into an upper Tm range (T > Tsep) forming a reshapeable actuation geometry that determines the skeleton and a lower Tm range (T < Tsep) that enables the temperature-controlled bidirectional actuation by crystallization-induced elongation and melting-induced contraction. The macroscopic bidirectional shape changes in TMPAs could be correlated with changes in the nanostructure of the crystallizable domains as a result of in situ X-ray investigations. Potential applications of TMPAs include heat engines with adjustable rotation rate and active building facades with self-regulating sun protectors. %0 journal article %@ 0142-9612 %A Sharifi, S., van Kooten, T.G., Kranenburg, H.J.C., Meij, B.P., Behl, M., Lendlein, A., Grijpma, D.W. %D 2013 %J Biomaterials %N 33 %P 8105-8113 %R doi:10.1016/j.biomaterials.2013.07.061 %T An annulus fibrosus closure device based on a biodegradable shape-memory polymer network %U https://doi.org/10.1016/j.biomaterials.2013.07.061 33 %X Injuries to the intervertebral disc caused by degeneration or trauma often lead to tearing of the annulus fibrosus (AF) and extrusion of the nucleus pulposus (NP). This can compress nerves and cause lower back pain. In this study, the characteristics of poly(d,l-lactide-co-trimethylene carbonate) networks with shape-memory properties have been evaluated in order to prepare biodegradable AF closure devices that can be implanted minimally invasively. Four different macromers with (d,l-lactide) to trimethylene carbonate (DLLA:TMC) molar ratios of 80:20, 70:30, 60:40 and 40:60 with terminal methacrylate groups and molecular weights of approximately 30 kg mol−1 were used to prepare the networks by photo-crosslinking. The mechanical properties of the samples and their shape-memory properties were determined at temperatures of 0 °C and 40 °C by tensile tests- and cyclic, thermo-mechanical measurements. At 40 °C all networks showed rubber-like behavior and were flexible with elastic modulus values of 1.7–2.5 MPa, which is in the range of the modulus values of human annulus fibrosus tissue. The shape-memory characteristics of the networks were excellent with values of the shape-fixity and the shape-recovery ratio higher than 98 and 95%, respectively. The switching temperatures were between 10 and 39 °C. In vitro culture and qualitative immunocytochemistry of human annulus fibrosus cells on shape-memory films with DLLA:TMC molar ratios of 60:40 showed very good ability of the networks to support the adhesion and growth of human AF cells. When the polymer network films were coated by adsorption of fibronectin, cell attachment, cell spreading, and extracellular matrix production was further improved. Annulus fibrosus closure devices were prepared from these AF cell-compatible materials by photo-polymerizing the reactive precursors in a mold. Insertion of the multifunctional implant in the disc of a cadaveric canine spine showed that these shape-memory devices could be implanted through a small slit and to some extent deploy self-sufficiently within the disc cavity. %0 journal article %@ 1616-5187 %A Yang, J., Lv, J., Behl, M., Lendlein, A., Yang, D., Zhang, L., Shi, C., Guo, J., Feng, Y. %D 2013 %J Macromolecular Bioscience %N 12 %P 1681-1688 %R doi:10.1002/mabi.201300264 %T Functionalization of Polycarbonate Surfaces by Grafting PEG and Zwitterionic Polymers with a Multicomb Structure %U https://doi.org/10.1002/mabi.201300264 12 %X The hemocompatibility of polycarbonateurethane (PCU) surfaces is improved by decoration with poly(poly(ethylene glycol) methacrylate) (poly(PEGMA)) and zwitterionic poly(3-((2-(methacryloyloxy)ethyl)dimethylammonio)propane-1-sulfonate) (poly(DMAPS)) blocks providing a novel multicomb structure obtained by application of surface-initiated atom transfer radical polymerization (s-ATRP) conditions. The PCU-poly(PEGMA-g-DMAPS) surface shows high hydrophilicity with a low contact angle of 20.6 ± 1.8°, while PCU-poly(PEGMA-b-DMAPS) surface exhibitsed a contact angle of 30.5 ± 2.6°. Furthermore, PCU-poly(PEGMA-g-DMAPS) surface shows very low platelet adsorption indicating that multicomb structure modified PCUs are preferred candidate materials for blood-contacting materials. %0 editorial %@ 1616-5187 %A Lendlein, A., Neffe, A.T. %D 2013 %J Macromolecular Bioscience %N 12 %P 1639-1639 %R doi:10.1002/mabi.201300507 %T Advanced Functional Polymers for Medicine %U https://doi.org/10.1002/mabi.201300507 12 %X The application of polymers in medicine requires tailored properties and functions. While properties are material inherent (e.g. thermal transitions, mechanical properties), functions can only be realized by combining a certain molecular structure with physical principles, such as the shape-memory effect based on entropy elasticity of a network and suitable phase transitions, while drug release is ruled by diffusion and interactions at interfaces. %0 journal article %@ 1616-5187 %A Neffe, A.T., Von Ruesten-Lange, M., Braune, S., Luetzow, K., Roch, T., Richau, K., Jung, F., Lendlein, A. %D 2013 %J Macromolecular Bioscience %N 12 %P 1720-1729 %R doi:10.1002/mabi.201300309 %T Poly(ethylene glycol) Grafting to Poly(ether imide) Membranes: Influence on Protein Adsorption and Thrombocyte Adhesion %U https://doi.org/10.1002/mabi.201300309 12 %X The chain length and end groups of linear PEG grafted on smooth surfaces is known to influence protein adsorption and thrombocyte adhesion. Here, it is explored whether established structure function relationships can be transferred to application relevant, rough surfaces. Functionalization of poly(ether imide) (PEI) membranes by grafting with monoamino PEG of different chain lengths (Mn = 1 kDa or 10 kDa) and end groups (methoxy or hydroxyl) is proven by spectroscopy, changes of surface hydrophilicity, and surface shielding effects. The surface functionalization does lead to reduction of adsorption of BSA, but not of fibrinogen. The thrombocyte adhesion is increased compared to untreated PEI surfaces. Conclusively, rough instead of smooth polymer or gold surfaces should be investigated as relevant models. %0 conference poster %@ %A Ullm, S., Tondera, C., Gebauer, T., Neffe, A.T., Lendlein, A., Pietzsch, J. %D 2013 %J World Conference on Regenerative Medicine, WCRM 2013 %T Gelatin-based biomaterials with tailorable mechanical properties as promising matrices for soft tissue replacement %U %X %0 conference lecture %@ %A Xu, X., Wang, W., Kratz, K., Li, Z., Jung, F., Ma, N., Lendlein, A. %D 2013 %J 32. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Cultivation of rat mesenchymal stem cells on poly(ether imide) surfaces with different microscaled roughness %U %X %0 journal article %@ 0177-9516 %A Harmsen, D., Lendlein, A., Schroeter, M., Scheffler, P., Duvinage, B. %D 2013 %J Praxis der Naturwissenschaften - Chemie in der Schule %N 4 %P 30-33 %T Bioabbaubare Polymere %U 4 %X Die in den letzten Jahren forcierte Forschung zu bioabbaubaren Polymeren führte zur Herstellung von biologisch abbaubaren Produkten für unterschiedliche Verwendungszwecke in der Medizin, der Biotechnologie und im Alltag. Insofern ist zu hinterfragen, inwieweit derartige Forschungsergebnisse für die Gestaltung von Chemieunterricht dienlich und mögliche Experimente für den unterrichtlichen Einsatz zu entwickeln sind. Dem folgend sollen im vorliegenden Beitrag erprobte Experimentieranordnungen zum hydrolytischen Abbau von Polymilchsäure-Folien vorgestellt werden. %0 conference poster %@ %A Mathew, S., Wischke, C., Roch, T., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Microparticulate carriers for modulating immune responses %U %X %0 conference poster %@ %A Karimi, M., Heuchel, M., Weigel, T., Kratz, K., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Influence of expansion cooling regime on morphology of poly(Epsilon-caprolactone) foams prepared by pressure quenching technique using supercritical CO2 %U %X %0 conference poster %@ %A Kusmierczuk, M., Baudis, S., Behl, M., Kratz, K., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Investigating the Influence of Water Uptake on the Mechanical Properties of Covalently Crosslinked Poly[(L-lactide)-co-glycolide] Polymer Networks %U %X %0 conference poster %@ %A Schoene, A.-C., Reuter, F., Richau, K., Kratz, K., Schulz, B., Reiche, J., Santer, S., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Langmuir Film Morphology of Poly(Epsilon-caprolactone) (PCL) and PCL-based Polyesterurethanes %U %X %0 conference poster %@ %A Schoene, A.-C., Kratz, K., Schulz, B., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Morphological Investigation of Oligo[(rac-lactide)-co-glycolide]-based Polyesterurethanes at the Water-Air Interface via Brewster Angle Microscopy and Ellipsometry %U %X %0 conference poster %@ %A Wang, L., Fang, L., Kratz, K., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Preparation of Two-Layered Magnetic Nanoparticles via a Two Step Surface-Initiated Ring-Opening Polymerization of Omega-Pentadecalactone and Epsilon-Caprolactone %U %X %0 conference poster %@ %A Farhan, M., Reddy, C., Kratz, K., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Two-way shape-memory properties of crystallizable, covalently crosslinked terpolymer networks %U %X %0 journal article %@ 0032-3861 %A Sisson, A.L., Ekinci, D., Lendlein, A. %D 2013 %J Polymer %N 17 %P 4333-4350 %R doi:10.1016/j.polymer.2013.04.045 %T The contemporary role of Epsilon-caprolactone chemistry to create advanced polymer architectures %U https://doi.org/10.1016/j.polymer.2013.04.045 17 %X Poly(ε-caprolactones) (PCLs) belong to the first generation of synthetic aliphatic polyesters. Their biodegradability motivated their extensive exploration as resorbable materials, particularly in controlled drug release applications. While PCL fell out of fashion due to the increasing popularity of shorter chain polyglycolides and derivatives, there has been a noticeable renewed interest in ε-caprolactone derived components for copolymer systems with advanced functions in the last decade or so. PCL has particular properties that are attractive for the design of tunable biomaterials such as slow crystallization kinetics and low melting temperatures in the physiological range. Slow degradation rates, with relatively minimal acid generation, can be valuable for prolonged drug release or longer-term stability of implants. Herein we cover recent developments of PCL chemistry, focussing on innovative uses of ε-caprolactone-based segments in sophisticated polymer architectures such as multiblock copolymer networks, and micellar systems. Such polymer constructs are of high interest for biomedical applications. %0 conference poster %@ %A Racheva, M., Julich-Gruner, K., Noechel, U., Neffe, A.T., Wischke, C., Lendlein, A. %D 2013 %J Advanced Functional Polymers for Medicine, 533th WE-Heraeus-Seminar %T Influence of drying procedures on network properties of physical gelatin hydrogels %U %X %0 conference poster %@ %A Zhang, P., Behl, M., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Influence of Metal Ions on the Mechanical Properties of Phosphine-based Coordination Polymer Networks %U %X %0 conference poster %@ %A Friess, F., Lendlein, A., Wischke, C. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Specific and unspecific photoinitiated radical crosslinking reactions of methacrylate functionalized oligo(Epsilon-caprolactone) %U %X %0 conference poster %@ %A Baudis, S., Behl, M., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T High-Throughput Synthesis as a Technology Platform for Copolymer Libraries %U %X %0 conference poster %@ %A Razzaq, M., Behl, M., Kratz, K., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Geometrically Controlled Triple-Shape Effect of Polymer Nanocomposites %U %X %0 conference poster %@ %A Fang, L., Yan, W., Zierke, M., Richau, K., Behl, M., Kratz, K., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Crystallization Behavior and Phase Separation in Spin Coated Copolyetherester Urethane Films with Different Diisocyanate Linkers %U %X %0 conference poster %@ %A Fang, L., Yan, W., Richau, K., Behl, M., Kratz, K., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Crystallization Behaviors of Biodegradable Multiblock Copolymers Based on Oligodepsipeptides in Spin-coated Films %U %X %0 conference poster %@ %A Reddy, C., Noechel, U., Wang, K., Cui, J., Behl, M., Kratz, K., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Influence of co-monomer composition and covalent netpoint density on temperature-memory performance of crystallizable copolymer networks %U %X %0 conference poster %@ %A Fang, L., Yan, W., Zierke, M., Behl, M., Kratz, K., Lendlein, A. %D 2013 %J Advanced Functional Polymers for Medicine, 533th WE-Heraeus-Seminar %T Morphology of Spin-coated Films from Copolyetheresterurethanes Containing Different Aliphatic Diisocyanate Linkers %U %X %0 conference poster %@ %A Feng, Y., Zhang, L., Behl, M., Lendlein, A., Shi, C., Lv, J., Yang, J. %D 2013 %J Advanced Functional Polymers for Medicine, 533th WE-Heraeus-Seminar %T Amphiphilic depsipeptide/PEG block copolymer Microspheres and release of doxorubicin %U %X %0 conference poster %@ %A Zhang, P., Behl, M., Lendlein, A. %D 2013 %J Advanced Functional Polymers for Medicine, 533th WE-Heraeus-Seminar %T Chemo-responsive Polymer Networks Based on Rhodium Coordination Bonds %U %X %0 lecture %@ %A Roch, T., Lendlein, A. %D 2013 %J %T Polymere als Biomaterialien %U %X %0 conference poster %@ %A Jiang, Y., Fang, L., Kratz, K., Lendlein, A. %D 2013 %J Advanced Functional Polymers for Medicine, 533th WE-Heraeus-Seminar %T AFM Study of the Crystallization Behavior of Temperature-Memory Polymers Containing Different Weight Contents of Crystallizable Poly(ε-caprolactone) Switching Segments %U %X %0 conference poster %@ %A Schoene, A.-C., Schulz, B., Richau, K., Kratz, K., Lendlein, A. %D 2013 %J 28. Tag der Chemie %T Characterization of Langmuir Layers Prepared from Copolyesterurethanes Containing Different Poly(ε-caprolactone) Moieties %U %X %0 conference poster %@ %A Zhang, Q., Sauter, T., Kratz, K., Lendlein, A. %D 2013 %J Advanced Functional Polymers for Medicine, 533th WE-Heraeus-Seminar %T Microparticles prepared from degradable copolyetherester urethanes via electrospraying %U %X %0 conference poster %@ %A Wang, L., Noechel, U., Fang, L., Kratz, K., Lendlein, A. %D 2013 %J Advanced Functional Polymers for Medicine, 533th WE-Heraeus-Seminar %T Impact of Polymer Network Architecture on the Thermal and Mechanical Properties of Multi-phase Polymer Networks Containing Crystallizable Poly(ethylene glycol) (PEG) and Poly(ε-caprolactone) (PCL) Segments %U %X %0 conference poster %@ %A Heuchel, M., Albrecht, W., Kosmella, H.-J., Kratz, K., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Experimental determination of vitrification points in ternary polymer/solvent/non-solvent/ systems %U %X %0 conference poster %@ %A Luetzow, K., Weigel, T., Kosmella, H.-J., Neffe, A.T., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Shape-Memory Effect of Polymeric Nanocomposite Polyether Urethane Foams with Magnetic Nanoparticles %U %X %0 conference poster %@ %A Stoermann, F., Roch, T., Wischke, C., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Microcapsules with an aqueous core for protein encapsulation %U %X %0 conference poster %@ %A Julich-Gruner, K., Roch, T., Neffe, A.T., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Functionalization of Polymers with the Amino Acid derived Moieties Desaminotyrosine and Desaminotyrosyl Tyrosine %U %X %0 conference poster %@ %A Ghobadi, E., Heuchel, M., Kratz, K., Lendlein, A. %D 2013 %J Advanced Functional Polymers for Medicine, 533th WE-Heraeus-Seminar %T Atomistic simulation of the shape-memory effect of switching segments in poly[(rac-lactide)-co-glycolide] polyesterurethanes %U %X %0 journal article %@ 1946-4274 %A Fang, L., Yan, W., Noechel, U., Zierke, M., Behl, M., Kratz, K., Lendlein, A. %D 2013 %J MRS Online Proceedings Library %P 57-64 %R doi:10.1557/opl.2013.805 %T Influence of Coupling Agent on the Morphology of Multifunctional, Degradable Shape-Memory Polymers %U https://doi.org/10.1557/opl.2013.805 %X Multifunctional polymer-based biomaterials, which combine degradability and shapememory capability, are promising candidate materials for biomedical implants. An example is a degradable multiblock copolymer (PDC), composed of poly(p-dioxanone) (PPDO) as hard and poly(ε-caprolactone) (PCL) as switching segments. PDC exhibits a unique linear mass loss during hydrolytic degradation, which can be tailored by the PPDO to PCL weight ratio, as well as an excellent thermally induced dual-shape effect. PDC can be synthesized by co-condensation of two oligomeric macrodiols (PCL-diol and PPDO-diol) using aliphatic diisocyanates as coupling agent. Here, we investigated whether different morphologies could be obtained for PDCs synthesized from identical oligomeric macrodiols (PCL-diol with M n = 2000 g·mol-1 and PPDO-diol with M n = 5300-5500 g·mol-1) with 2, 2(4), 4-trimethyl-hexamethylene diisocyanate (TMDI) and 1, 6-hexamethylene diisocyanate (HDI), respectively. More specifically, atomic force microscopy (AFM) was utilized for an investigation of the surface morphologies in solution casted PDC thin films in the temperature range from 20 °C to 60 °C. The results obtained in differential scanning calorimetry (DSC) and AFM demonstrated that different morphologies were obtained when TMDI (PDC-TMDI) or HDI (PDC-HDI) were used as linker. PCL related crystals in PDC-HDI were more heterogeneous and less ordered than those in PDCTMDI, while HDI resulted in a larger degree of crystallinity than TMDI. This research provides some new suggestions for choosing a suitable coupling agent to tailor the required morphologies and properties of SMPs with crystallizable switching segments. %0 journal article %@ 1946-4274 %A Tartivel, L., Behl, M., Schroeter, M., Lendlein, A. %D 2013 %J MRS Online Proceedings Library %P 135-140 %R doi:10.1557/opl.2013.840 %T ABA triblock copolymer based hydrogels with thermo-sensitivity for biomedical applications %U https://doi.org/10.1557/opl.2013.840 %X Oligo(ethylene glycol)-oligo(propylene glycol)-oligo(ethylene glycol) (OEG-OPG-OEG) triblock copolymers are hydrogel forming and extensively investigated in the field of drug release due to their biocompatibility and thermo-sensitivity. Here the synthesis and characterization of OEG-OPG-OEG based polymer networks from methacrylated oligomers by photo-irradiation are reported. Two precursors were selected to have comparable hydrophilicity (80 wt% OEG content) but different molecular weights of M n = 8400 g·mol-1 and 14600 g·mol-1. The precursor solutions were prepared in concentration 10 to 30 wt%. The resulting polymer networks prepared from high M n precursors exhibited higher swellability at equilibrium (up to 3400%) and mechanical properties in the range of G’ ∼ 0.1 to 1 kPa at 5 °C compared to networks based on low M n precursors. A more significant thermo-sensitive behavior in terms of swellability, volumetric contraction and mechanical transition, starting at 30 °C could also be observed for the networks based on high M n precursors, thus promoting future application in the field of drug release. %0 conference lecture %@ %A Behl, M., Lendlein, A. %D 2013 %J Nanomaterials for Biomedical Applications, 3rd Sino-German Symposium 2013 %T Stimuli-sensitive Biomaterials %U %X %0 conference lecture %@ %A Wischke, C., Krueger, A., Roch, T., Lendlein, A. %D 2013 %J Jahrestagung der Deutschen Pharmazeutischen Gesellschaft 2013 %T Polymer-dependent endocytosis kinetics of nanoparticles and relevance of environmental conditions %U %X %0 conference poster %@ %A Zhang, Q., Sauter, T., Wang, L., Fang, L., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Preparation of magneto-sensitive nanocomposite microparticles from copolyesterurethanes via electrospraying %U %X %0 conference poster %@ %A Rijckaert, B., Pierce, B.F., Neffe, A.T., Goers, J., Roch, T., Gebauer, T., Smink, J.J., Lendlein, A., Gossen, M., Leutz, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Evaluation of Gelatin Hydrogels in their Interaction with Monocytic Osteoclast Precursor Cells %U %X %0 conference lecture %@ %A Behl, M., Lendlein, A. %D 2013 %J Nanomaterials for Biomedical Applications, 3rd Sino-German Symposium 2013 %T Introduction Note %U %X %0 conference poster %@ %A Sauter, T., Kratz, K., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Controlling the Shape-Memory Properties in Polymeric Foams by Microstructural Design %U %X %0 conference poster %@ %A Saatchi, M., Behl, M., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Preparation and Characterization of Double Layer Porous Structure by Injection Molding %U %X %0 conference poster %@ %A Jiang, Y., Fang, L., Kratz, K., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T The Effect of Fixation Temperature on Crystallization Behaviors and Shape-Memory Properties of a Semi-Crystalline Multiblock Copolymer %U %X %0 conference poster %@ %A Yan, W., Fang, L., Noechel, U., Behl, M., Kratz, K., Lendlein, A. %D 2013 %J 12th International Conference on Polymers for Advanced Technologies, PAT 2013 %T Influence of Strain Rate on the Shape-Memory Performance of Multiblock Copolymers Comprising Crystallizable Poly(Epsilon-caprolactone) Switching and Poly[3-(S)-isobutylmorpholine-2,5-dione] Hard Segments %U %X %0 journal article %@ 1386-0291 %A Jung, F., Schulz, C., Blaschke, F., Muller, D.N., Mrowietz, C., Franke, R.P., Lendlein, A., Schunck, W.-H. %D 2012 %J Clinical Hemorheology and Microcirculation %N 2-4 %P 403-416 %R doi:10.3233/CH-2012-1614 %T Effect of cytochrome P450-dependent epoxyeicosanoids on Ristocetin-induced thrombocyte aggregation %U https://doi.org/10.3233/CH-2012-1614 2-4 %X Epoxyeicosatrienoic acids (EETs) produced by cytochrome P450 (CYP)-dependent epoxidation of arachidonic acid (AA) inhibit thrombocyte adhesion to the vascular wall. Upon dietary omega-3 fatty acid supplementation, EETs are partially replaced by eicosapentaenoic acid (EPA)-derived epoxyeicosatetraenoic acids (EEQs) and docosahexaenoic acid (DHA)-derived epoxydocosapentaenoic acids (EDPs). We hypothesized that the omega-3 epoxy-metabolites may exhibit superior anti-thrombogenic properties compared to their AA-derived counterparts. To test this hypothesis, we analyzed the effects of 11,12-EET, 17,18-EEQ and 19,20-EDP on Ristocetin-induced thrombocyte aggregation (RITA), a process that mimics thrombocyte adhesion to the vascular wall. The eicosanoids were added for 5, 30, or 60 minutes to thrombocyte-rich plasma freshly prepared immediately after blood collection from stringently selected apparently healthy subjects. Thrombocyte aggregation was then induced by Ristocetin (0.75 mg/mL) and assessed by turbidimetric measurements. After 60 minutes of preincubation, all three epoxy-metabolites significantly decreased the rate of RITA. 17,18-EEQ and 19,20-EDP were effective already at 1 μM, whereas 5-fold higher concentrations were required with 11,12-EET. Addition of AUDA, an inhibitor of the soluble epoxide hydrolase, potentiated the effect of 17,18-EEQ resulting in a significant further decrease of the velocity as well as amplitude of the aggregation process. In contrast to their profound effects on RITA, none of the epoxy-metabolites was effective in reducing collagen- or ADP-induced thrombocyte aggregation. These results indicate a highly specific role of CYP-eicosanoids in preventing thromboembolic events and suggest that the formation of 17,18-EEQ and 19,20-EDP may contribute to the anti-thrombotic effects of omega-3 fatty acids. %0 journal article %@ 0959-9428 %A Ekinci, D., Sisson, A.L., Lendlein, A. %D 2012 %J Journal of Materials Chemistry %N 39 %P 21100-21109 %R doi:10.1039/c2jm34271e %T Polyglycerol-based polymer network films for potential biomedical applications %U https://doi.org/10.1039/c2jm34271e 39 %X Synthetic polymeric materials are established as being central to many modern approaches to medical treatments such as biomaterial induced tissue regeneration or drug eluting implants. Cytocompatible, antifouling materials, based on hydrophilic polymers such as poly(ethylene glycol), have been widely studied as a ‘blank canvas’ substrate; it is possible to apply various bioactive ligands to elicit specific tissue and cell responses. In recent years, branched polyglycerols have gained attention as a viable alternative to PEG as a protein-resistance providing chemical moiety. To this end we have embarked on the preparation of bulk polyglycerol-based films, which are readily synthesized from abundant starting materials, with the aim of evaluating their as yet undiscovered potential as macroscopic biomaterials. Herein we report syntheses, as well as mechanical, and rheological properties of a series of polyglycerol-based polymer networks. Polymeric films produced are highly crosslinked, have high thermal stability, and are flexible with thermal glass transition temperatures below body temperature. %0 journal article %@ 1788-618X %A Kumar, U.N., Kratz, K., Behl, M., Lendlein, A. %D 2012 %J eXPRESS Polymer Letters %N 1 %P 26-40 %R doi:10.3144/expresspolymlett.2012.4 %T Shape-memory properties of magnetically active triple-shape nanocomposites based on a grafted polymer network with two crystallizable switching segments %U https://doi.org/10.3144/expresspolymlett.2012.4 1 %X materials as here the temporary shape (A) was predominantly fixed by PCL crystallites. %0 journal article %@ 1616-301X %A Kratz, K., Voigt, U., Lendlein, A. %D 2012 %J Advanced Functional Materials %N 14 %P 3057-3065 %R doi:10.1002/adfm.201200211 %T Temperature-Memory Effect of Copolyesterurethanes and their Application Potential in Minimally Invasive Medical Technologies %U https://doi.org/10.1002/adfm.201200211 14 %X Minimally invasive surgery often requires devices that can change their geometry or shape when placed inside the body. Here, the potential of thermoplastic temperature-memory polymers (TMP) for the design of intelligent devices, which can be programmed by the clinician to individually adapt their shifting geometry and their response temperature Tsw to the patient's needs, is explored. Poly(ω-pentadecalactone) as hard segments and poly(ϵ-caprolactone) segments acting as crystallizable controlling units for the temperature-memory effect (TME) are chosen to form multiblock copolymers PDLCL. These components are selected according to their thermal properties and their good biocompatibility. Response temperatures obtained under stress-free and constant strain recovery can be systematically adjusted by variation of the deformation temperature in a temperature range from 32 °C to 65 °C, which is the relevant temperature range for medical applications. The working principle of TMP based instruments for minimally invasive surgical procedures is successfully demonstrated using three temperature-memory catheter concepts: individually programmable TM-catheter, an in-situ programmable TM-catheter, and an intelligent drainage catheter for gastroenterology. %0 journal article %@ 1520-6106 %A Yoshikawa, Y.Y., Cui, J., Kratz, K., Matsuzaki, T., Nakabayashi, S., Marx, A., Engel, U., Lendlein, A., Tanaka, M. %D 2012 %J The Journal of Physical Chemistry B %N 28 %P 8024-8030 %R doi:10.1021/jp212385p %T Quantitative Evaluation of Adhesion of Osteosarcoma Cells to Hydrophobic Polymer Substrate with Tunable Elasticity %U https://doi.org/10.1021/jp212385p 28 %X We investigated a potential application of hydrophobic poly(n-butyl acrylate) networks (cPnBA) as substrates with tunable elasticity for culturing, maintenance, and regulation of human osteosarcoma cells (U2OS). Nanoindentation experiments with an atomic force microscope revealed that the mechanical properties of cPnBA films are maintained under aqueous conditions, confirming that the substrate elasticity can be controlled simply by the degree of cross-linking, independent from the culture medium. We found that the adhesion U2OS cells to cPnBA substrates could be improved by surface treatments such as oxgen plasma and serum proteins. To determine the strength of cell adhesion, the critical pressure to detach cells from cPnBA substrates was measured using a shock wave induced by an intensive picosecond laser pulse. A monotonic increase in the cell adhesion strength in accordance with the substrate elasticity demonstrated the potential of intrinsically hydrophobic cPnBA as a new class of substrate material with tunable mechanical properties that are not influenced by the culture medium. %0 journal article %@ 0959-9428 %A Razzaq, M.Y., Behl, M., Frank, U., Koetz, J., Szczerba, W., Lendlein, A. %D 2012 %J Journal of Materials Chemistry %P 9237-9243 %R doi:10.1039/c2jm16146j %T Oligo(Omega-pentadecalactone) decorated magnetic nanoparticles %U https://doi.org/10.1039/c2jm16146j %X Hybrid magnetic nanoparticles (mgNP) with a magnetite core diameter of 10 ± 1 nm surface functionalized with oligo(ω-pentadecalactone) (OPDL) oligomers with Mn between 1300 and 3300 g mol−1 could be successfully prepared having OPDL grafted from 200 mg g−1 to 2170 mg g−1. The particles are dispersible in chloroform resulting in stable suspensions. Magnetic response against an external magnetic field proved the superparamagnetic nature of the particles with a low coercivity (Bc) value of 297 µT. The combination of the advantageous superparamagnetism of the mgNP with the exceptional stability of OPDL makes these novel hybrid mgNP promising candidates as multifunctional building blocks for magnetic nanocomposites with tunable physical properties. %0 journal article %@ 0014-3057 %A Matsumoto, H., Ishiguro, T., Konosu, Y., Minagawa, M., Tanioka, A., Richau, K., Kratz, K., Lendlein, A. %D 2012 %J European Polymer Journal %N 11 %P 1866-1874 %R doi:10.1016/j.eurpolymj.2012.07.008 %T Shape-memory properties of electrospun non-woven fabrics prepared from degradable polyesterurethanes containing poly(Omega-pentadecalactone) hard segments %U https://doi.org/10.1016/j.eurpolymj.2012.07.008 11 %X Microscaled non-woven fabrics with fiber diameters in the range 1.8–3.1 μm were prepared by electrospinning from a chloroform solution of a degradable multiblock copolymer (PDLCL) consisting of crystallizable poly(ω-pentadecalactone) hard segments (PPDL) and poly(ε-caprolactone) switching segments (PCL). The surface morphology and microstructure of the non-woven fabrics were characterized by scanning electron microscopy, temperature-controlled scanning probe microscopy, wide angle X-ray diffraction (WAXD), and small angle X-ray scattering (SAXS). The microstructural analysis demonstrated that the rod-like domains of hard segment (PPDL) formed in the electrospun PDLCL fiber functioned as physical crosslinks. Cyclic, thermomechanical tensile tests showed that the electrospun PDLCL fabrics exhibited good shape-memory properties with strain recovery rates of Rr = 89–95% and strain fixity rates of Rf = 82–83% after the 2nd cycle, when small deformations were applied at clinically relevant temperatures. %0 conference poster %@ %A Wischke, C., Schneider, C., Neffe, A.T., Lendlein, A. %D 2012 %J 2nd Symposium on Innovative Polymers for Controlled Delivery, SIPCD 2012 %T Sustained release hydrogels by in situ polymerized coating with polyalkylcyanoacrylates %U %X %0 conference lecture %@ %A Xu, X., Wang, W., Kratz, K., Li, Z., Roch, T., Jung, F., Ma, N., Lendlein, A. %D 2012 %J 14th International Congress of Biorheology, 7th International Conference on Clinical Hemorheology %T Different polymer surfaces influence in vitro cultivation of rat mesenchymal stem cells %U %X %0 journal article %@ 1386-0291 %A Scharnagl, N., Hiebl, B., Trescher, K., Zierke, M., Behl, M., Kratz, K., Jung, F., Lendlein, A. %D 2012 %J Clinical Hemorheology and Microcirculation %N 2-4 %P 295-311 %R doi:10.3233/CH-2012-1606 %T Behaviour of fibroblasts on water born acrylonitrile-based copolymers containing different cationic and anionic moieties %U https://doi.org/10.3233/CH-2012-1606 2-4 %X The chemical composition of a substrate can influence the adhesion, viability and proliferation of cells seeded on the substrate. The aim of this work was to investigate the influence of different cationic or anionic moieties in acrylonitrile-based copolymers on the interaction with fibroblasts. A series of ten different types of acrylonitrile-based copolymers with a random sequence structure was prepared using a water born synthesis process to exclude potential residues of organic solvents. As charged comonomers cationic methacrylic acid-2-aminoethylester hydrochloride (AEMA), N-3-amino-propyl-methacrylamide hydrochloride (APMA) and anionic 2-methyl-2-propene-1-sulfonic acid sodium salt (NaMAS) were utilized. By application of a specific sintering procedure the copolymer materials were processed into transparent disks for conducting cell tests in direct contact. The copolymers were analyzed with respect to their composition and surface properties. Cytotoxicity tests of the polymer extracts, as well as of the disks were performed with L929 mouse fibroblasts. All copolymers showed no cytotoxic effects. Furthermore, for higher molar ratios of AEMA an increase in cell growth could be observed, which might be a hint that higher charge densities are favorable for the proliferation of L929 cells. %0 journal article %@ 1386-0291 %A Jung, F., Goers, J., Roch, T., Zaupa, A., Pierce, B., Neffe, A.T., Lendlein, A. %D 2012 %J Clinical Hemorheology and Microcirculation %N 1-2 %P 55-63 %R doi:10.3233/CH-2011-1443 %T Physically crosslinked gelatins functionalized with tyrosine moieties do not induce angiogenesis or thrombus formation in the developing vasculature in the avian chorioallantoic membrane %U https://doi.org/10.3233/CH-2011-1443 1-2 %X Gelatins functionalized with desaminotyrosine or desaminotyrosyl tyrosine form physically crosslinked polymer networks due to the interactions between the introduced aromatic moeties. In the swollen state, their mechanical properties can be tailored in a range similar to the elasticity of soft tissues. The aim of this study was to evaluate their potential as biomaterials by determining whether these materials – in comparison to plain gelatin – induce bleedings, thrombotic processes, or angiogenesis. These investigations were performed using the hen's egg chorioallantoic membrane (HETCAM) assay. These results indicate that the gelatin-based hydrogels did not possess angiogenic effects and also did not induce bleedings, thrombotic processes or vessel destruction (avascular zones). The biocompatibility of the materials in vitro motivates the exploration of their application as matrix in local drug-release systems with short half-life times (1 hour up to several days). %0 journal article %@ 1386-0291 %A Roch, T., Krueger, A., Kratz, K., Ma, N., Jung, F., Lendlein, A. %D 2012 %J Clinical Hemorheology and Microcirculation %N 2-4 %P 375-389 %R doi:10.3233/CH-2012-1612 %T Immunological evaluation of polystyrene and poly(ether imide) cell culture inserts with different roughness %U https://doi.org/10.3233/CH-2012-1612 2-4 %X For the successful clinical and biological application of polymers, their interaction with cells, tissues, and body fluids has to be well characterized. In order to investigate how the physical, chemical, and mechanical properties of candidate biomaterials influence cell behaviours, the testing sample is usually placed in commercially available cell culture plates. Thus, not only the testing sample itself but also the culture dish material might influence the cell behaviour. Therefore, an insert system was created to exclude this influence and allow investigations of the testing material solely. In this study micropatterned inserts prepared from polystyrene (PS) as well as from poly(ether imide) (PEI) with three different roughness levels of i) Rq = 0.12 μm (PS) and 0.23 μm (PEI); ii) Rq = 3.52 μm (PS) and 3.92 μm (PEI); and iii) Rq = 16.04 μm (PS) and 22.65 μm (PEI) were explored with regard of their immuno-compatibility including the determination of potential contaminations with endotoxins or other microbial products. The endotoxin levels of the inserts were determined to be less than 0.07 EU/mL, which is well below the U.S. Food and Drug Administration limit of 0.5 EU/mL and the survival of murine macrophages cultured in the inserts was not impaired. Activation of early immune mechanisms such as complement activation and the generation of reactive oxygen species could not be observed. All tested materials had no influence on the cytokine secretion from cells of whole human blood. The investigated inserts were immuno-compatible and apparently free of contaminations with microbial products. The roughness of the inserts had no stimulatory or inhibitory effect on early immune mechanisms. Conclusively, the 24-well plate insert systems introduced in this study allow investigating the interactions of tailored surface properties such as roughness with many other cell types, without the disadvantage of the standard commercially available culture vessels influencing the biomaterial testing. %0 journal article %@ 1386-0291 %A Wang, W., Ma, N., Kratz, K., Xu, X., Li, Z., Roch, T., Bieback, K., Jung, F., Lendlein, A. %D 2012 %J Clinical Hemorheology and Microcirculation %N 2-4 %P 357-373 %R doi:10.3233/CH-2012-1611 %T The influence of polymer scaffolds on cellular behaviour of bone marrow derived human mesenchymal stem cells %U https://doi.org/10.3233/CH-2012-1611 2-4 %X Mesenchymal stem cells (MSCs) are multipotent stem cells that can differentiate into a variety of cell types. Therefore, they are widely explored in regenerative medicine. The interaction of MSCs with biomaterials is of great importance for cell proliferation, differentiation and function, and can be strongly influenced by numerous factors, such as the chemical nature and the mechanical properties of the material surface. In this study, we investigated the interaction of bone marrow derived human MSCs with different amorphous and transparent polymers namely polystyrene (PS), polycarbonate (PC), poly(ether imide) (PEI), polyetherurethane (PEU) and poly(styrene-co-acrylonitrile) (PSAN). To ensure that the MSCs were solely in contact to the testing material we applied polymeric inserts, which were prepared from the aforementioned polymers via injection molding. The explored inserts exhibited a similar wettability with advancing contact angles ranging from 84 ± 7° (PEU) to 99 ± 5° (PS) and a surface roughness of Rq ≤ 0.86 μm. The micromechanical properties determined by AFM indentation varied from 6 ± 1 GPa (PEU) to 24 ± 5 GPa (PSAN). Cells presented different adhesion rates on the polymer surfaces 24 hours after seeding (45 ± 7% (PS), 63 ± 1% (PC), 75 ± 4% (PEI), 69 ± 2% (PEU) and 61 ± 5% (PSAN)). The cells could proliferate on the polymer surfaces, and the fold change of cell number after 16 days of culture reached to 1.93 ± 0.07 (PS), 3.38 ± 0.11 (PC), 3.65 ± 0.04 (PEI), 2.24 ± 0.15 (PEU) and 3.36 ± 0.09 (PSAN). Differences in cell apoptosis could be observed during the culture. After 7 days, the apoptosis of cells on PC, PEI and PSAN decreased to a level comparable to that on standard tissue culture plate (TCP). All of the tested polymers exhibited low cytotoxicity and allowed high cell viability. Compared to cells on TCP, cells on PC and PEI showed similar morphology, distribution as well as F-actin cytoskeleton organization, whereas cells on PSAN were distributed less evenly and cells on PEU were less oriented. Cells were more likely to form clusters on PS. Conclusively, we demonstrated the influence of polymer substrates on the cellular behaviour of MSCs, which could be included in the development of novel design concepts based on polymeric biomaterials. %0 journal article %@ 1022-1336 %A Lange, M., Braune, S., Luetzow, K., Richau, K., Scharnagl, N., Weinhart, M., Neffe, A.T., Jung, F., Haag, R., Lendlein, A. %D 2012 %J Macromolecular Rapid Communications %N 17 %P 1487-1492 %R doi:10.1002/marc.201200426 %T Surface Functionalization of Poly(ether imide) Membranes with Linear, Methylated Oligoglycerols for Reducing Thrombogenicity %U https://doi.org/10.1002/marc.201200426 17 %X Materials for biomedical applications are often chosen for their bulk properties. Other requirements such as a hemocompatible surface shall be fulfilled by suitable chemical functionalization. Here we show, that linear, side-chain methylated oligoglycerols (OGMe) are more stable to oxidation than oligo(ethylene glycol) (OEG). Poly(ether imide) (PEI) membranes functionalized with OGMes perform at least as good as, and partially better than, OEG functionalized PEI membranes in view of protein resistance as well as thrombocyte adhesion and activation. Therefore, OGMes are highly potent surface functionalizing molecules for improving the hemocompatibility of polymers. %0 journal article %@ 1616-301X %A Razzaq, M.Y., Behl, M., Lendlein, A. %D 2012 %J Advanced Functional Materials %N 1 %P 184-191 %R doi:10.1002/adfm.201101590 %T Magnetic Memory Effect of Nanocomposites %U https://doi.org/10.1002/adfm.201101590 1 %X The magnetic memory effect (MME) is the ability of magneto-sensitive materials to remember the magnetic field strength (Hdef), at which they were deformed recently. They respond close to Hdef either by recovering their initial shape at a switching magnetic field strength Hsw under stress-free conditions or by building up stress with a peak maximum at Hσ,max under constant strain conditions. This paper explores whether such a MME can be created for polymer-based nanocomposites. The concept is based on temperature-memory polymers (TMP) as matrix, in which silica coated iron(III)oxide nanoparticles (mNP) are dispersed. The MME was explored in a cyclic magneto-mechanical test, in which the nanocomposite sample was elongated to ϵm while being exposed to an alternating magnetic field at Hdef. The magnetic memory was read out by determining Hσ,max or Hsw. A linear correlation between Hσ,max (or Hsw) and Hdef in a range from 15 to 23 kA m−1 at a fixed frequency of f = 258 kHz is observed and demonstrates the excellent magnetic memory properties of the investigated nanocomposites containing either crystallizable or amorphous, vitrifiable domains as controlling units. The deformation ϵm at Hdef can be fixed with an accuracy of more than 72% and the initial shape can be recovered almost completely by more than 86%. The MME allows the design of magnetically programmable devices such as switches or mechanical manipulators. %0 journal article %@ 1386-0291 %A Schneider, T., Kohl, B., Sauter, T., Kratz, K., Lendlein, A., Ertel, W., Schulze-Tanzil, G. %D 2012 %J Clinical Hemorheology and Microcirculation %N 2-4 %P 325-336 %R doi:10.3233/CH-2012-1608 %T Influence of fiber orientation in electrospun polymer scaffolds on viability, adhesion and differentiation of articular chondrocytes %U https://doi.org/10.3233/CH-2012-1608 2-4 %X Degradable polymers with a tailorable degradation rate might be promising candidate materials for biomaterial-based cartilage repair. In view of the poor intrinsic healing capability of cartilage, implantation of autologous chondrocytes seeded on a biocompatible slow degrading polymer might be an encouraging approach to improve cartilage repair in the future. This study was undertaken to test if the fiber orientation (random versus aligned) of two different degradable polymers and a polymer intended for long term applications could influence primary articular chondrocytes growth and ultrastructure. A degradable copoly(ether)esterurethane (PDC) was synthesized via co-condensation of poly(p-dioxanone)diol and poly(ε-caprolactone)diol using an aliphatic diisocyanate as linker. Poly(p-dioxanone) (PPDO) was applied as commercially available degradable polymer, while polyetherimide (PEI) was chosen as biomaterial enabling surface functionalization. The fibrous scaffolds of PDC and PPDO were obtained by electrospinning using 1,1,1,3,3,3 hexafluoro-2-propanol (HFP), while for PEI dimethyl acetamide (DMAc) was applied as solvent. Primary porcine articular chondrocytes were seeded at different cell densities on the fibrous polymer scaffolds and analyzed for viability (fluorescein diacetate/ethidiumbromide staining), for type II collagen synthesis (immunolabelling), ultrastructure and orientation on the fibers (SEM: scanning electron microscopy). Vital chondrocytes adhered on all electrospun scaffolds irrespective of random and aligned topologies. In addition, the chondrocytes produced the cartilage-specific type II collagen on all tested polymer topologies suggesting their differentiated functions. SEM revealed an almost flattened chondrocytes shape on scaffolds with random fiber orientation: whereby chondrocytes growth remained mainly restricted to the scaffold surface. On aligned fibers the chondrocytes exhibited a more spindle-shaped morphology with rougher cell surfaces but only a minority of the cells aligned according to the fibers. As a next step the reduction of the fiber diameter of electrospun scaffolds should be addressed as an important parameter to mimic cartilage ECM structure. %0 conference poster %@ %A Tzoneva, R., Seifert, B., Behl, M., Lendlein, A. %D 2012 %J 31. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Elastic multiblock copolymers for vascular regeneration: Protein adsorption and hemocompatibility %U %X %0 journal article %@ 1386-0291 %A Tzoneva, R., Seifert, B., Behl, M., Lendlein, A. %D 2012 %J Clinical Hemorheology and Microcirculation %N 2-4 %P 337-348 %R doi:10.3233/CH-2012-1609 %T Elastic multiblock copolymers for vascular regeneration: Protein adsorption and hemocompatibility %U https://doi.org/10.3233/CH-2012-1609 2-4 %X Hemocompatibility of elastic multiblock copolymers PDC, based on poly(p-dioxanone) (PPDO)/poly(ε-caprolactone)-segments, capable of a shape-memory effect, and PDD, based on PPDO/poly((adipinate-alt-1,4-butanediol)-co-(adipinate-alt-ethylene glycol)-co-adipinate-alt-diethylene glycol)-segments, was studied in order to assess their suitability for an application aiming at blood vessels regeneration. The results were compared with polypropylene (PP) which is a widely used blood-contacting material for devices as blood oxygenators and dialysis tubes. Protein adsorption studies showed diverse blood plasma proteins in a relatively high amount on both elastic polymers compared to the poor amount of plasma proteins adsorbed on PP. Study of the coagulation system revealed high thrombin formation on PDC and no difference in plasma kallikrein activation between elastic multiblock copolymers and the reference PP. Activation of complement system was higher for PDC followed by PDD and lower for PP. However, platelet adhesion and activation were hardly suppressed on the multiblock copolymers compared to the PP surface, where the number of adhered platelets and the activation rate were significant. The present results reveal that the tested multiblock copolymers with improved elastic properties and shape-memory capability (PDC) show low thrombogenicity and are promising candidates for vascular tissue engineering. %0 conference lecture %@ %A Wischke, C., Schossig, M., Lendlein, A. %D 2012 %J Materials Science and Engineering, MSE 2012 %T Microscopic characterization of particulate SMP matrices %U %X %0 conference lecture %@ %A Wischke, C., Mathew, S., Roch, T., Frentsch, M., Lendlein, A. %D 2012 %J Jahrestagung der Deutschen Pharmazeutischen Gesellschaft 2012 %T Modulating immune responses of human cells by adjuvant loaded particulate carriers %U %X %0 journal article %@ 1386-0291 %A Braune, S., Alagoez, G., Seifert, B., Lendlein, A., Jung, F. %D 2012 %J Clinical Hemorheology and Microcirculation %N 2-4 %P 349-355 %R doi:10.3233/CH-2012-1610 %T Automated image-based analysis of adherent thrombocytes on polymer surfaces %U https://doi.org/10.3233/CH-2012-1610 2-4 %X A dataset of 439 confocal laser scanning microscopic images was analyzed to investigate the potential of an image-based automated analysis for identifying and assessing adherent thrombocytes on polymer surfaces. Parameters for image optimization of glutardialdehyde induced fluorescence images were classified and data mining was performed using the Java image processing software ImageJ. Previously reported analysis required that each thrombocyte had to be identified interactively and outlined manually. Now, we were able to determine the number and area of adherent thrombocytes with high accuracy (spearman correlation coefficient r = 0.98 and r = 0.99) using a two-stage filter-set, including a rolling ball background subtraction- and a watershed segmentation-algorithm. Furthermore, we could proof a significant correlation between these parameters (spearman correlation coefficient r = 0.97), determining both as suitable predictors for the evaluation of material induced thrombogenicity. The here reported image-based automated analysis can be successfully applied to identify and measure adherent thrombocytes on polymer surfaces and, thus, might be successfully integrated in a high-throughput screening process to evaluate biomaterial hemocompatibility. %0 journal article %@ 1386-0291 %A Rueder, C., Sauter, T., Kratz, K., Peter, J., Jung, F., Lendlein, A., Zohlnhoefer, D. %D 2012 %J Clinical Hemorheology and Microcirculation %N 2-4 %P 313-323 %R doi:10.3233/CH-2012-1607 %T Smooth muscle and endothelial cell behaviour on degradable copolyetheresterurethane films %U https://doi.org/10.3233/CH-2012-1607 2-4 %X Stent thrombosis and restenosis after drug-eluting stent (DES) implantation remains a relevant problem in the cardiovascular field. The polymer-based biomaterial (e.g. stent coating) requirements are comprehensive, since the polymeric material ideally should ensure an effective re-endothelialization by recruiting endothelial cells (EC) and endothelial progenitor cells (EPC). Simultaneously, the polymer should effectively prevent adherence of smooth muscle cells (SMC) and thereby inhibiting restenosis. The aim of this study was to gain a basic understanding on the interaction of SMC and human umbilical vein endothelial cells (HUVEC) with nonporous polymer films. A multifunctional copolyetheresterurethane (PDC) was chosen as candidate material: PDC consists of poly(p-dioxanone) (PPDO) and poly(ε-caprolactone)-segments (PCL). In our study it was compared to the degradable PPDO homopolymer and poly(vinylidene fluoride-co-hexafluoropropene) (PVDF), an established coating material of DES in clinical applications intended for longterm applications. The films were analyzed according to their thermomechanical and surface properties before being examined in contact with HUVEC and SMC concerning cell viability, proliferation and adhesion. Experimental results showed that adhesion could be improved for HUVEC on PDC compared to PPDO and PVDF. In contrast, SMC attachment is largely suppressed on PDC polymeric films indicating a cell-specific response of HUVEC towards PDC. In conclusion, PDC represents a promising candidate material for future cardiovascular applications like e.g. biodegradable (PDC) stent coatings. %0 conference poster %@ %A Wischke, C., Mathew, S., Roch, T., Frentsch, M., Lendlein, A. %D 2012 %J 12th European Symposium on Controlled Drug Delivery, ESCDD 2012 %T Potential of NOD Ligands as Immune Modulators in Particulate Vaccine Carriers %U %X %0 journal article %@ 1438-1656 %A Sauter, T., Luetzow, K., Schossig, M., Kosmalla, H., Weigel, T., Kratz, K., Lendlein, A. %D 2012 %J Advanced Engineering Materials %N 9 %P 818-824 %R doi:10.1002/adem.201200127 %T Shape-Memory Properties of Polyetherurethane Foams Prepared by Thermally Induced Phase Separation %U https://doi.org/10.1002/adem.201200127 9 %X In this study, we report the preparation of two structurally different shape-memory polymer foams by thermally induced phase separation (TIPS) from amorphous polyetherurethanes. Foams with either a homogeneous, monomodal, or with a hierarchically structured, bimodal, pore size distribution are obtained by adoption of the cooling protocol. The shape-memory properties have been investigated for both foam structures by cyclic, thermomechanical experiments, while the morphological changes on the micro scale (pore level) have been compared to the macro scale by an in situ micro compression device experiment. The results show that the hierarchically structured foam achieves higher shape-recovery rates and a higher total recovery as compared to the homogeneous foam, which is due to an increased energy storage capability by micro scale bending of the hierarchically structured foam compared to pure compression of the homogeneous foam. %0 conference lecture (invited) %@ %A Wischke, C., Lendlein, A. %D 2012 %J 4th International Conference on Smart Materials, Structures and Systems, CIMTEC 2012 %T Shape-Memory Polymers as Drug Carrier – Points to be considered %U %X %0 journal article %@ 1386-0291 %A Schulz, C., Ruesten-Lange, M.v., Krueger, A., Lendlein, A., Jung, F. %D 2012 %J Clinical Hemorheology and Microcirculation %N 2-4 %P 267-282 %R doi:10.3233/CH-2012-1604 %T Viability and function of primary human endothelial cells on smooth poly(ether imide) films %U https://doi.org/10.3233/CH-2012-1604 2-4 %X Poly(ether imide) (PEI) is being explored as potential biomaterial for cardiovascular applications. Different studies showed that human umbilical venous endothelial cells (HUVEC) are able to adhere and proliferate on PEI membranes (Rq = 13.20 ± 1.58 nm). A recently published study revealed evidence for much lower platelet adhesion on very smooth PEI-films (Rq = 2.37 ± 1.40 nm). Therefore, we explored whether primary human venous endothelial cells (HUVEC) are able to adhere and proliferate on such very smooth PEI-films compared to tissue-cultured polystyrene (TCP) as reference material. Cytotoxicity testing revealed that PEI had a slight cytotoxic effect on HUVEC accompanied by a marginal reduced integrity of the plasma membrane and a significant lower mitochondrial activity. However long-term seeding experiments up to eleven days exhibited that HUVEC were able to proliferate on the PEI-films till confluence (TCP 96,190 ± 18,289 cells/cm2; PEI 91,590 ± 19,583 cells/cm2). Further studies are planned to monitor the influence of shear force on the endothelial cell monolayer in a dynamic test system to determine its stability in view of shear resistant endothelialization of PEI for cardiovascular devices. %0 journal article %@ 1386-0291 %A Krueger, A., Braune, S., Kratz, K., Lendlein, A., Jung, F. %D 2012 %J Clinical Hemorheology and Microcirculation %N 2-4 %P 283-294 %R doi:10.3233/CH-2012-1605 %T The influence of poly(n-butyl acrylate) networks on viability and function of smooth muscle cells and vascular fibroblasts %U https://doi.org/10.3233/CH-2012-1605 2-4 %X Background: The patency of small-diameter vascular prostheses is limited by several factors such as thrombogenicity, which is strongly influenced by surface roughness and chemical composition, or a mechanical mismatch between the elastic modulus of an artery and of the vascular prosthesis. A confluent layer of endothelial cells onto the inner surface of vascular prostheses could improve the hemocompatibility of the device. Biomaterials with adjustable elastic properties could be tailored to the values of human arteries so that a prothesis mismatch could be avoided. It was recently demonstrated that a co-culture of endothelial cells with angiogenically stimulated monocytes (aMO2) shows an accelerated formation of a functional confluent endothelial cell monolayer on soft hydrophobic poly(n-butyl acrylate) (cPnBA) networks. In addition, the cell compatibility with vascular smooth muscle cells and aortic fibroblasts, which are other important cell types of the vessel wall, is essential for a vascular prosthesis material and must therefore be explored. Purpose: Here we investigated the interaction of human vascular smooth muscle cells and aortic fibroblasts with cPnBA04 and cPnBA73. Material and methods: Human primary vascular smooth muscle cells and aortic fibroblasts were seeded on the two cPnBAs with different elastic moduli (cPnBA04 - 250 kPa and cPnBA73 - 1100 kPa) over 72 h. A live-dead staining (fluorescein diacetate/propium iodide) was performed to determine the morphology and viability of adherent cells. Furthermore, the extracellular matrix components, the actin cytoskeleton, the cell-material-contacts and the cytokine profiles were analysed. Results: Both cell types adhered and were viable on cPnBA04 and cPnBA73. The level of pro-inflammatory cytokine secretion (IFN-γ and TNF-α) by smooth muscle cells and vascular fibroblasts was comparable to that of cells cultivated on a control material. The release of these cytokines by human fibroblasts was higher on cPnBA73 compared to cPnBA04. Both cell types secreted an extracellular matrix comparable to cells seeded on a control material. Conclusion: The study revealed, that cPnBA with varying elastic moduli are not only suitable for the cultivation of endothelial cells, but also for human vascular smooth muscle cells and aortic fibroblasts. Therefore, cPnBA could be a potential candidate material for the development of cardiovascular prostheses. %0 journal article %@ 1386-0291 %A Trescher, K., Scharnagl, N., Kratz, K., Roch, T., Lendlein, A., Jung, F. %D 2012 %J Clinical Hemorheology and Microcirculation %N 2-4 %P 391-401 %R doi:10.3233/CH-2012-1613 %T Adherence and viability of primary human keratinocytes and primary human dermal fibroblasts on acrylonitrile-based copolymers with different concentrations of positively charged functional groups %U https://doi.org/10.3233/CH-2012-1613 2-4 %X As shown in several studies, various properties of biomaterials such as stiffness, surface roughness, chemical composition or the amount of functional groups at the surface can influence adhesion, viability, proliferation and functionalities of cells. The aim of this work was to explore whether a cell-selective effect could be achieved for acrylonitrile-based copolymers containing different contents of positively charged functional groups, which were introduced by incorporation of methacrylic acid-2-aminoethylester hydrochloride (AEMA) units. The p(AN-co-AEMA) copolymers were synthesized by suspension polymerization in water and processed into disk shaped test specimen via a sintering process to ensure the absence of organic solvents in the copolymers. Copolymers with an AEMA content of 1.4, 1.6, and 4.4 mol-% were investigated according to their cell-selective capacity, which should support the adhesion, viability and proliferation of keratinocytes, while the adherence of fibroblasts should rather be disabled. The test samples were seeded with primary human keratinocytes and primary human dermal fibroblasts in mono- as well as in co-cultures. Tissue culture plate polystyrene (TCP) was used to control the physiologic growth of the cells. Density and viability of attached and non-adherent cells were analyzed by live/dead staining, lactate dehydrogenase (LDH) assay and flow cytometry with DAPI staining. For the assured discrimination of adherent cell types in coculture a keratin/vimentin-staining was performed. On copolymers with 4.4 mol-% AEMA adherent keratinocytes in monoculture and cocultured keratinocytes and fibroblasts showed a higher viability, a lower impairment of cell membranes and higher densities of viable cells compared to both other copolymers. For adherent fibroblasts these parameters did not differ between the copolymers and an increasing ratio of keratinocytes to fibroblasts in cocultures were found with increasing AEMA content. The results showed that keratinocytes and fibroblasts can be influenced by copolymers with different contents of positively charged functional groups. Since the tendency of a better adherence and viability of keratinocytes with increasing amounts of positively charged functional groups was shown, the potential enhancement by further increase of the amount of positively charged functional groups shall be tested in a future study. %0 conference lecture %@ %A Schneider, T., Kohl, B., Sauter, T., Kratz, K., Lendlein, A., Ertel, W., Schulze-Tanzil, G. %D 2012 %J 31. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Influence of fiber orientation in electrospun polymer scaffolds on viability, adhesion and differentiation of articular chondrocytes %U %X %0 journal article %@ 1793-9844 %A Sauter, T., Weigel, T., Kratz, K., Lendlein, A. %D 2012 %J Nano LIFE %N 1 %P 1230005 %R doi:10.1142/S1793984411000372 %T Polymer Scaffolds for Regenerative Therapies – Design of Hierarchically Organized Structures and their Morphological Characterization %U https://doi.org/10.1142/S1793984411000372 1 %X Read More: http://www.worldscientific.com/doi/abs/10.1142/S1793984411000372 %0 journal article %@ 1438-7492 %A Sisson, A.L., Lendlein, A. %D 2012 %J Macromolecular Materials and Engineering %N 12 %P 1135-1137 %R doi:10.1002/mame.201200369 %T Advances in actively moving polymers %U https://doi.org/10.1002/mame.201200369 12 %X No abstract %0 journal article %@ 0168-3659 %A Wischke, C., Mathew, S., Roch, T., Frentsch, M., Lendlein, A. %D 2012 %J Journal of Controlled Release %N 3 %P 299-306 %R doi:10.1016/j.jconrel.2012.06.034 %T Potential of NOD receptor ligands as immunomodulators in particulate vaccine carriers %U https://doi.org/10.1016/j.jconrel.2012.06.034 3 %X Microparticles have been intensively explored as next generation vaccine carriers in the last decade. They were mostly loaded with toll-like receptor ligands as adjuvants, which are not finally rated for their safety profile. Here, ligands of cytosolic receptors sensing nucleotide and oligomerization domains (NOD) were explored as alternative adjuvants in combination with immunologically inert particulate carriers from poly[(rac-lactide)-co-glycolide], which were shown to be capable to coencapsulate protein antigens as well as γ-d-glutamyl-meso-diaminopimelic acid (iE-DAP) and N-acetylmuramyl‐l-alanyl‐d-isoglutamine (MDP) as NOD receptor agonists. For selectively studying the immunomodulatory potency of the adjuvants rather than of potential immunogenic impurities and for providing a strategy for quality control of future particulate vaccines, the purity of the microparticles was confirmed with different reporter cell lines selectively expressing specific pathogen recognition receptors. Microencapsulated NOD ligands but not blank microparticles were shown to induce a dose-dependent maturation of human monocyte-derived dendritic cells to a proinflammatory phenotype with high levels of released cytokines particularly for iE-DAP. These data suggest their further exploration in vivo. %0 conference lecture %@ %A Neffe, A.T., Lendlein, A. %D 2012 %J TERM - Trends and challenges in Regenerative Medicine - Towards interregional collaboration in Europe %T Biomaterials for Regenerative Medicine %U %X %0 journal article %@ 1386-0291 %A Rueder, C., Sauter, T., Becker, T., Kratz, K., Hiebl, B., Jung, F., Lendlein, A., Zohlnhoefer, D. %D 2012 %J Clinical Hemorheology and Microcirculation %N 1-2 %P 101-112 %R doi:10.3233/CH-2011-1447 %T Viability, proliferation and adhesion of smooth muscle cells and human umbilical vein endothelial cells on electrospun polymer scaffolds %U https://doi.org/10.3233/CH-2011-1447 1-2 %X A major clinical problem of high relevance in the cardiovascular field is late stent thrombosis after implantation of drug eluting stents (DES). Clinical widely used DES currently utilize durable polymer coatings, which can induce persistent arterial wall inflammation and delayed vascular healing resulting in an impaired endothelialization. In this study we explored the interaction of smooth muscle cells (SMC) and human umbilical vein endothelial cells (HUVEC) with electrospun scaffolds prepared from resorbable polyetheresterurethane (PDC) and poly(p-dioxanone) (PPDO), as well as polyetherimide (PEI), which can be surface modified, in comparison to poly(vinylidene fluoride-co-hexafluoropropene) (PVDF) as reference material, which is established as coating material of DES in clinical applications. Our results show that adhesion could be improved for HUVEC on PDC, PPDO and PEI compared to PVDF, whereas almost no SMC attached to the scaffolds indicating a cell-specific response of HUVEC towards the different fibrous structures. Proliferation and apoptosis results revealed that PPDO and PEI have no significant negative influence on vitality and cell cycle behaviour compared to PVDF. Hence, they represent promising candidates for temporary blood vessel support that induce HUVEC attachment and prevent SMC proliferation. %0 conference lecture (invited) %@ %A Behl, M., Feng, Y., Zotzmann, J., Razzaq, M., Lendlein, A. %D 2012 %J Kolloqium des Brandernburger Polymerverbandes %T Recent Developments in Shape-Memory and Triple-Shape Materials %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2012 %J SPE ANTEC and NPE 2012 %T Multifunctional Polymer Networks and their Application Potential in Medicine %U %X %0 conference lecture %@ %A Krueger, A., Braune, S., Kratz, K., Lendlein, A., Jung, F. %D 2012 %J 31. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T The influence of poly(n-butyl acrylate) networks on viability and function of smooth muscle cells and vascular fibroblasts %U %X %0 conference lecture %@ %A Krueger, A., Mrowietz, C., Lendlein, A., Jung, F. %D 2012 %J 14th International Congress of Biorheology, 7th International Conference on Clinical Hemorheology %T Interaction of human venous endothelial cells with platelets in vitro: Influence of platelet concentration %U %X %0 conference poster %@ %A Goers, J., Mayer, A., Zaupa, A., Pierce, B., Neffe, A.T., Lendlein, A., Jung, F. %D 2012 %J 31. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Influence of physically (DAT) crosslinked gelatin on the vasculature in the avian chorioallantoic membrane %U %X %0 conference poster %@ %A Trescher, K., Kratz, K., Roch, T., Juenger, M., Jung, F., Lendlein, A. %D 2012 %J 39. Annual Meeting of the Arbeitsgemeinschaft Dermatologische Forschung %T Behaviour of primary human keratinocytes and fibroblasts on soft poly(n-butyl acrylate) networks with tailored mechanical properties %U %X %0 journal article %@ 0896-8446 %A Karimi, M., Heuchel, M., Weigel, T., Schossig, M., Hofmann, D., Lendlein, A. %D 2012 %J The Journal of Supercritical Fluids %N 1 %P 175-190 %R doi:10.1016/j.supflu.2011.09.022 %T Formation and size distribution of pores in poly(Epsilon-caprolactone) foams prepared by pressure quenching using supercritical CO2 %U https://doi.org/10.1016/j.supflu.2011.09.022 1 %X Many biomaterial-based regenerative therapies require foam structures, which temporarily mimic the extracellular matrix. The pore structure of these scaffolds needs to be tailored to the specific requirements of the clinical application. Poly(ɛ-caprolactone) (PCL) is a semi-crystalline, aliphatic polyester, which is applied as degradable implant material. In this paper we explored how thermodynamic and kinetic conditions in a supercritical CO2 (scCO2) supported foaming process influence the final morphology of the foam. With help of a view cell, we have systematically investigated the foaming with scCO2 in the pressure range from 78 to 200 bar at temperatures between 25 and 50 °C. Foams were obtained both above the pressure dependent melting temperature (Tm) but also below this temperature, i.e. from supercooled melt states. Foams were characterized by μCT X-ray computed tomography and scanning electron microscopy. The pore size distributions of the obtained foams show characteristic properties (widths, maxima) depending on the initial thermodynamic state of the CO2/PCL system before pressure quenching, the rate of the pressure decay, and the thermal history of the system. We try to rationalize the dependency of foam morphology and quench conditions with thermodynamic model calculations. The initial amount of CO2 in the PCL melt was calculated with the Sanchez-Lacombe equation of state. Pressure quenching with a slow pressure decay rate is considered an isothermal process where for a fast rate an adiabatic process is assumed. Both processes differ in their phase separation mechanism. It turned out that the CO2-induced melting point depression of the semi-crystalline polymer is an important factor. The variation of foaming conditions allows the preparation of scaffolds with specific morphological parameters (mean pore size, pore distribution, and pore connectivity). %0 journal article %@ 1946-4274 %A Wischke, C., Steuer, S., Lendlein, A. %D 2012 %J MRS Online Proceedings Library %P 31-36 %R doi:10.1557/opl.2012.224 %T Determining loading kinetics of drug releasing degradable shape-memory polymers %U https://doi.org/10.1557/opl.2012.224 %X Modern concepts for biofunctional implants often comprise the controlled release of bioactive compounds to gain specific biofunctionalities. Here, amorphous and semi-crystalline copolyester-based shape-memory polymer (SMP) networks are reported as matrix for pharmaceutical applications. Drug loading of such crosslinked networks by swelling techniques requires tools to determine the actual payload. In this report, the capability of determining loading kinetics by mass increase or changes of drug concentration in the swelling medium is explored for two types of copolyester-based SMP networks differing in their crosslinking chemistry. Nitrofurantoin and ethacridine lactate served as hydrophobic and hydrophilic model drugs. It was found, that the absolute values of the determined payload did not systematically agree with those obtained by the more reliable technique of network cleavage and spectrophotometric quantification. However, the studies indicate that for both types of SMP materials and both drugs, maximum incorporation of the drugs occurred within a few hours. The time until equilibration depended on the network properties. %0 journal article %@ 1946-4274 %A Sauter, T., Kratz, K., Lendlein, A. %D 2012 %J MRS Online Proceedings Library %P 49-54 %R doi:10.1557/opl.2012.251 %T Shape-Memory Properties of Electrospun Non-wovens Prepared from Amorphous Polyetherurethanes Under Stress-free and Constant Strain Conditions %U https://doi.org/10.1557/opl.2012.251 %X The shape-memory properties of electrospun polyetherurethanes (PEU) non-wovens with a single fiber diameter of around 1 μm were explored. In uniaxial cyclic, thermomechanical tensile tests a dual-shape shape-memory creation procedure (SMCP) was applied and the shape recovery was examined under stress-free and constant strain conditions. The thermal properties of the electrospun PEU non-wovens were found to be similar to those obtained for bulk PEU samples, whereas the mechanical properties revealed differences with respect to the elongation at break (εb) at increased temperatures. Excellent dual-shape properties were achieved for the PEU non-wovens with a high shape fixity rate (Rf) and shape recovery rate (Rr). A significant higher recovery stress (σmax) was obtained under constant strain recovery conditions for the electrospun non-wovens compared to the bulk PEU samples, which might be attributed to the higher degree of orientation of the polymer chains in the microfibers. Therefore the influence of different (single) fiber diameters as well as the variation of the programming elongation εm and temperature Tprog on σmax is an interesting issue for future investigations. %0 journal article %@ 1946-4274 %A Zotzmann, J., Behl, M., Lendlein, A. %D 2012 %J MRS Online Proceedings Library %P 43-48 %R doi:10.1557/opl.2012.250 %T Triple-Shape Effect of Copolymer Networks Based on Poly(Omega-pentadecalactone) and Poly(Epsilon-caprolactone) Segments Applying a Programming Procedure with an Adjusted Temperature Profile %U https://doi.org/10.1557/opl.2012.250 %X A triple-shape material based on the two crystallizable segments poly(ω‑pentadeca-lactone) and poly(ε-caprolactone) was synthesized by crosslinking star-shaped precursors. A newly developed programming procedure (TSCP2) was applied in order to achieve triple-shape behavior. The application of this modified triple-shape creation procedure enabled triple-shape capability by influencing the crystallization behavior of the two switching segments in these copolymer networks, which partly show no two distinct and separated melting points. The influence of molecular weight and content of the poly(ε-caprolactone) segment on the triple-shape effect programmed by application of TSCP2 was investigated. %0 journal article %@ 1946-4274 %A Piece, B.F., Neffe, A.T., Lendlein, A. %D 2012 %J MRS Online Proceedings Library %P 13-18 %R doi:10.1557/opl.2012.221 %T Using Mass Spectrometry to Investigate the Structural Features of Photocrosslinked Co-Networks based on Gelatin and Poly(ethylene glycol) Methacrylates %U https://doi.org/10.1557/opl.2012.221 %X Gelatin was functionalized with glycidyl methacrylate and photocrosslinked in the presence of poly(ethylene glycol) dimethacrylate (PEGDMA) or poly(ethylene glycol) monomethacrylate (PEGMA) to create a biopolymer-based system with tailorable properties. These co-networks were hydrolyzed using 6 M HCl and the degradation products were analyzed and identified using matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry. This technique successfully identified gelatin-derived peptides such as FLPEPPE, SFLPEPPE, and SFLPEPPEE as well as an accompanying PEG-g-poly(methacrylic acid) component. No oligo- or polymethacrylates were monitored at any molecular weight range above m/z = 500, which indicated that they possessed lower molecular weights. An in vitro hydrolytic degradation experiment performed in pH 7.4 PBS buffer solution at 37 °C showed that these networks, which were prepared without the addition of a potentially toxic photoinitiator, exhibited mass loss of up to 50 wt% at 6 weeks of incubation time. These results provide valuable insight into how these functional gelatin-based co-network biomaterials will perform in a biological setting. %0 journal article %@ 1386-0291 %A Roch, T., Cui, J., Kratz, K., Lendlein, A., Jung, F. %D 2012 %J Clinical Hemorheology and Microcirculation %N 1-2 %P 131-142 %R doi:10.3233/CH-2010-1449 %T Immuno-compatibility of soft hydrophobic poly (n-butyl acrylate) networks with elastic moduli for regeneration of functional tissues %U https://doi.org/10.3233/CH-2010-1449 1-2 %X The need for engineered devices to treat cardiovascular diseases is increasing due to an aging population and a changing lifestyle. Soft poly(n-butyl acrylate) (cPnBA) networks were recently described as polymer networks with adjustable mechanical properties and suggested as soft substrates for cells, which could potentially be used for cardiovascular implants. Vascular prostheses designed to be implanted in arteries should have an elasticity similar to blood vessels (elastic modulus at body temperature between 100 and 1200 kPa). Therefore, cPnBA networks with E-moduli of 250 kPa (cPnBA0250) and 1100 kPa (cPnBA1100) were developed. Recently, it was shown that both materials were non-cytotoxic for murin fibroblasts, human primary endothelial cells and human monocytes. However, before such newly developed polymers can be used in vivo, it has to be assured that the sterilized materials have a very low endotoxin load to avoid an unspecific activation of the immune system, which otherwise might cause local or systemic inflammatory responses and could lead to severe pathologies. In this study we investigated the immuno-compatibility of sterilized cPnBA0250 and cPnBA1100 with the help of an immuno-competent macrophage cell line as well as with whole human blood. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2012 %J 9th International Conference and Workshop on Bio-Barriers, Biological Barriers 2012 %T Biocompatible Polymers %U %X %0 journal article %@ 1616-5187 %A Pierce, B.F., Pittermann, E., Ma, N., Gebauer, T., Neffe, A.T., Hoelscher, M., Jung, F., Lendlein, A. %D 2012 %J Macromolecular Bioscience %N 3 %P 312-321 %R doi:10.1002/mabi.201100237 %T Viability of Human Mesenchymal Stem Cells Seeded on Crosslinked Entropy-Elastic Gelatin-Based Hydrogels %U https://doi.org/10.1002/mabi.201100237 3 %X Biomimetic polymer network systems with tailorable properties based on biopolymers represent a class of degradable hydrogels that provides sequences for protein adsorption and cell adhesion. Such materials show potential for in vitro MSC proliferation as well as in vivo applications and were obtained by crosslinking different concentrations of gelatin using varying amounts of ethyl lysine diisocyanate in the presence of a surfactant in pH 7.4 PBS solution. Material extracts, which were tested for cytotoxic effects using L929 mouse fibroblasts, were non-toxic. The hydrogels were seeded with human bone marrow-derived MSCs and supported viable MSCs for the incubation time of 9 d. Preadsorption of fibronectin on materials improved this biofunctionality. %0 journal article %@ 1616-5187 %A Pierce, B.F., Tronci, G., Roessle, M., Neffe, A.T., Jung, F., Lendlein, A. %D 2012 %J Macromolecular Bioscience %N 4 %P 484-493 %R doi:10.1002/mabi.201100232 %T Photocrosslinked Co-Networks from Glycidylmethacrylated Gelatin and Poly(ethylene glycol) Methacrylates %U https://doi.org/10.1002/mabi.201100232 4 %X Biopolymer-based systems with adjustable macroscopic properties that can be varied in a wide range using only small changes in chemical composition are promising candidates for biomaterial-induced autoregeneration. Glycidylmethacrylated gelatin is photopolymerized with the addition of PEG mono- or dimethacrylate to form co-networks in pH = 7.4 PBS. The degree of swelling (Q) and water uptake (H) in PBS at 37 °C are tailorable for PEGDMA co-networks (Q ≈ 250–650 vol%), while the storage modulus of swollen networks at 37 °C can be adjusted by the PEG(D)MA content (G′ = 0.7–145 kPa). Indirect cytotoxicity tests on ethylene oxide sterilized films show non-toxic responses for the homonetwork and all but one PEGDMA-containing co-networks materials. %0 conference poster %@ %A Wang, W., Kratz, K., Xu, X., Li, Z., Roch, T., Jung, F., Ma, N., Lendlein, A. %D 2012 %J 31. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T The influence of polymeric materials on cellular behaviors of bone marrow derived human mesenchymal stem cells %U %X %0 conference poster %@ %A Trescher, K., Jung, F., Scharnagl, N., Roch, T., Lendlein, A. %D 2012 %J 31. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Adherence and viability of primary human keratinocytes and primary human dermal fibroblasts on acrylonitrile based copolymers with increasing amounts of AEMA %U %X %0 conference poster %@ %A Braune, S., Seifert, B., Lendlein, A., Jung, F. %D 2012 %J 31. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Automated image-based analysis of adherent thrombocytes on polymer surfaces %U %X %0 conference poster %@ %A Schulz, C., Lange, M., Lendlein, A., Jung, F. %D 2012 %J 31. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Viability and function of primary human endothelial cells on smooth poly(ether imide) films %U %X %0 conference poster %@ %A Roch, T., Krueger, A., Kratz, K., Ma, N., Jung, F., Lendlein, A. %D 2012 %J 31. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Immuno-compatibility of polystyrene and poly(ether imide) with different roughness %U %X %0 conference lecture %@ %A Wischke, C., Lendlein, A. %D 2012 %J RMIB Beiratssitzung, Forschungsarbeiten im BCRT %T Polymer based biomaterials %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2012 %J Kunststoffe an Hochschulen und Institutionen in unserer Region, VDI Arbeitskreis Kunststofftechnik, Netzwerktreffen Berlin / Brandenburg %T Vorstellung des Zentrums fuer Biomaterialentwicklung %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2012 %J Kolloquium am Institut fuer Radiopharmazie, HZDR %T Design Principles for Multifunctional, Polymer-based Biomaterials %U %X %0 journal article %@ 0160-564X %A Mayer, A., Kratz, K., Hiebl, B., Lendlein, A., Jung, F. %D 2012 %J Artificial Organs %N 3 %P E28-E38 %R doi:10.1111/j.1525-1594.2011.01410.x %T Interaction of angiogenically stimulated intermediate CD163+ monocytes/macrophages with soft hydrophobic poly(n-butyl acrylate) networks with elastic moduli matched to that of human arteries %U https://doi.org/10.1111/j.1525-1594.2011.01410.x 3 %X Seeded on cPnBA, aMO2 – unaffected by the elastic moduli of both substrates – seemed to remain in their subset status and secreted VEGF-A165 without release of pro-inflammatory cytokines. These in vitro results might indicate that this MO subset can be used as cellular delivery system for pro-angiogenic and non-inflammatory mediators to support the endothelialization of cPnBA. %0 journal article %@ 0920-5063 %A Hiebl, B., Cui, J., Kratz, K., Frank, O., Schossig, M., Richau, K., Lee, S., Jung, F., Lendlein, A. %D 2012 %J Journal of Biomaterials Science - Polymer Edition %N 7 %P 901-915 %R doi:10.1163/092050611X566144 %T Viability, Morphology and Function of Primary Endothelial Cells on Poly(Eta-Butyl Acrylate) Networks Having Elastic Moduli Comparable to Arteries %U https://doi.org/10.1163/092050611X566144 7 %X Soft hydrophobic poly(n-butyl acrylate) networks (cPnBA) were developed as entropy elastic substrates for passive mechanical stimulation of cells, where the elastic modulus of the cPnBAs could be systematically adjusted by variation of the cross-link density. The networks were synthesized by thermally-induced radical polymerization from n-butyl acrylate, with poly(propylene glycol) dimethacrylate (PPGDMA) acting as cross-linker, whereby the purity of the cPnBAs was confirmed by (1)H-NMR spectroscopy and gas chromatography. In this work two cPnBA polymer networks with an elastic modulus around 200 kPa and 1 MPa were investigated having an elastic modulus similar to that of arteries. Both cPnBAs exhibited an almost smooth surface with a surface roughness (R(q)) in the wet state ranging from 17 to 37 nm and a similar zeta-potential, indicating an almost identical chemical composition within the topmost surface layer in terms of functional groups. In contrast, wettability of the samples was found to be different with an advancing angle (θ(advancing)) of 1233.8 for cPnBA0250, while for cPnBA1100 significantly lower values for θ(advancing) (1113.8) were obtained. First in vitro tests were performed with primary endothelial cells (HUVEC) to study its effects on vascular cell functions. Within the time period of cultivation (72 h), the cells on the cPnBA samples reached subconfluence and showed a viability rate of almost 100%. Although cell density differed after 72 h with more cells on cPnBA0250 than on cPnBA1100, both materials showed no significant effect on the cell morphology, the cellular LDH-release, which was used as marker for the integrity of the cell membrane, and the organisation of the VE-cadherin. However, lower cell density and less actin stress fibre formation on cPnBA1100 might indicate that cell-material interaction was weaker on cPnBA1100 than on cPnBA0250. The secretion of the vasoactive cytokines prostacyclin (PGI2) and thromboxane A2 (TXA2) was low compared to previously reported values. However, the anti-thrombogenic ratio of PGI2/TXA2 - which is balanced under physiological conditions - with much higher PGI2 compared to TXA2 (up to 17.6-fold after 72 h for cPnBA1100) suggests that this material might be effective to preventing thrombosis. %0 conference lecture (invited) %@ %A Lendlein, A., Wischke, C., Mathew, S., Roch, T., Kratz, K. %D 2012 %J 12th European Symposium on Controlled Drug Delivery, ESCDD 2012 %T Multifunctional Polymer-based Carrier Systems %U %X %0 conference lecture %@ %A Goers, J., Krueger, A., Gebauer, T., Pierce, B.F., Neffe, A.T., Lendlein, A., Jung, F. %D 2012 %J 14th International Congress of Biorheology, 7th International Conference on Clinical Hemorheology %T Influence of chemically crosslinked gelatin on the vasculature in the avian chorioallantoic membrane %U %X %0 journal article %@ 1946-4274 %A Melchert, C., Behl, M., Lendlein, A. %D 2012 %J MRS Online Proceedings Library %P 79-84 %R doi:10.1557/opl.2012.369 %T Phase Transition Behavior of Main Chain Nematic Liquid-Crystalline Polymers Based on 2-methyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone and 2-tert-butyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone %U https://doi.org/10.1557/opl.2012.369 %X The control of phase transition behavior in liquid crystalline polymers could enable potential application in the field of actuators and sensors by enabling a higher actuator performance of liquid crystalline elastomers (LCE). In this context the phase transition behavior of siloxane based liquid crystalline copolymers synthesized from 1,1,3,3-tetramethyldisiloxane, 2-methyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone (M-MeHq), and 2-tert-butyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone (M-tBHq) was explored. The selected monomers provided different thermal stabilities of the nematic phase, while the non-flexible siloxane spacer suppressed a smectic phase. The mesogenic properties were studied by means of differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and wide angle X-ray scattering (WAXS). With increasing fraction of M-MeHq the nematic phase of the copolymer was stabilized and a tailoring of relatively low TNI was achieved. %0 conference lecture %@ %A Lendlein, A. %D 2012 %J Institutspraesentation ECRN General Assembly %T Welcome to HZG Campus Teltow - Centre of Biomaterial Development %U %X %0 journal article %@ 1438-7492 %A Melchert, C., Behl, M., Noechel, U., Lendlein, A. %D 2012 %J Macromolecular Materials and Engineering %N 12 %P 1203-1212 %R doi:10.1002/mame.201200238 %T Influence of Comesogens on the Thermal and Actuation Properties of 2-tert-Butyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone Based Nematic Main-Chain Liquid Crystalline Elastomers %U https://doi.org/10.1002/mame.201200238 12 %X Although the shape-changing capabilities of LCEs hold great potential for applications ranging from micropumps to artificial muscles, customization of the LCE functionality to the applications' requirements is still a challenge. It is studied whether the orientation of NMC-LCPs and NMC-LCEs based on 2-tert-butyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone can be enhanced by copolymerization with 2-methyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone or 2,6-bis[4-(4-pentenyl-oxy)-benzoyl]anthracene. An increasing content of the comonomers stabilizes the nematic phase, which enables a tailoring of TNI for the NMC-LCP between 45 and 68 °C, while for the NMC-LCE TNI ranges between 69 and 76 °C. In addition, NMC-LCE show an increased actuation performance. %0 conference lecture (invited) %@ %A Neffe, A.T., Lendlein, A. %D 2012 %J Medi-WING, Medizintechnik im BMBF-Foerderprogramm WING %T Zukunftsperspektiven in der Biomaterialforschung %U %X %0 conference poster %@ %A Neffe, A.T., Lange, M., Braune, S., Luetzow, K., Jung, F., Scharnagl, N., Richau, K., Weinhart, M., Haag, R., Lendlein, A. %D 2012 %J Advanced Functional Polymers for Medicine, AFPM 2012 %T Surface Functionalization of Poly(ether imide) with Linear, Methylated Oligoglycerols to Increase the Hemocompatibility %U %X %0 conference lecture (invited) %@ %A Neffe, A.T., Behl, M., Jung, F., Pierce, B.F., Lendlein, A. %D 2012 %J Smart Collaborations Seminar %T Biopolymer-Based Materials for Medical Applications %U %X %0 conference lecture (invited) %@ %A Neffe, A.T., Pierce, B.F., Jung, F., Ma, N., Lendlein, A. %D 2012 %J Chemistry Seminar University of Adelaide %T Biomimetic Polymers for Biomedical Applications %U %X %0 conference lecture (invited) %@ %A Neffe, A.T., Pierce, B.F., Jung, F., Ma, N., Lendlein, A. %D 2012 %J Chemistry Seminar Flinders University %T Biomimetic Polymers for Biomedical Applications %U %X %0 conference poster %@ %A Julich-Gruner, K.K., Neffe, A.T., Lendlein, A. %D 2012 %J Polydays 2012 %T Synthesis and characterization of oligo(ethylene glycol)s functionalized with desaminotyrosine or desaminotyrosyltyrosine %U %X %0 journal article %@ 0906-6705 %A Trescher, K., Kratz, K., Roch, T., Juenger, M., Jung, F., Lendlein, A. %D 2012 %J Experimental Dermatology %N 3 %P e1-e58 %R doi:10.1111/j.1600-0625.2011.01428.x %T Behaviour of primary human keratinocytes and fibroblasts on soft poly(n-butyl acrylate) networks with tailored mechanical properties %U https://doi.org/10.1111/j.1600-0625.2011.01428.x 3 %X No abstract %0 journal article %@ %A Neffe, A.T., Lendlein, A. %D 2012 %J Berliner Wirtschaftsgespraeche, Themenbroschuere 2012, Gesundheitsstandort Berlin und Brandenburg %P 73-74 %T Biomaterialien: Ein Gewinn fuer die Regenerative Medizin und den Gesundheitsstandort Berlin-Brandenburg %U %X Biomaterialien sind Bestandteil regenerativer Therapien. Durch Vernetzung von herausragender Grundlagenforschung, klinischer Forschung mit Anwendungsorientierter Forschung und Entwicklung sowie einer interdisziplinären Ausbildung wird die gesamte Entwicklungskaskade abgebildet, so dass die Biomaterialforschung in der Region Berlin-Brandenburg einen internationalen Spitzenplatz belegt. %0 conference lecture %@ %A Jung, F., Mrowietz, C., Schulz, C., Blaschke, F., Mueller, D., Lendlein, A., Schunck, W.-H. %D 2012 %J 31. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Epoxyeicosatetraenoic acid analogs and Ristozetin-induced platelet aggregation %U %X %0 journal article %@ 1742-7061 %A Mayer, A., Roch, T., Kratz, K., Lendlein, A., Jung, F. %D 2012 %J Acta Biomaterialia %N 12 %P 4253-4259 %R doi:10.1016/j.actbio.2012.08.011 %T Pro-angiogenic CD14++ CD16+ CD163+ monocytes accelerate the in vitro endothelialization of soft hydrophobic poly(n-butyl acrylate) networks %U https://doi.org/10.1016/j.actbio.2012.08.011 12 %X As the majority of the polymers used as cardiovascular grafts so far do not match the elasticity of human arteries (100–1000 kPa) and the required endothelialization, a multifunctional material approach is needed to allow the adjustment of the mechanical properties while at the same time exhibiting a haemocompatible surface. Recently soft poly(n-butyl acrylate) networks (cPnBA) with adjustable mechanical properties were introduced as candidate materials with a surface that can be endothelialized. In this study, angiogenically stimulated intermediate CD163+ monocytes/macrophages (aMO2) were utilized as a cellular cytokine release system to realize the functional endothelialization of the hydrophobic cPnBA surface. We investigated the influence of co-cultured aMO2 on the morphology, density and cytokine secretion of human umbilical venous endothelial cells (HUVEC) seeded on cPnBA with an elastic modulus of around 250 kPa (cPnBA0250). A functional confluent HUVEC monolayer could be developed in the co-culture within 3 days. In contrast, the HUVEC in the monoculture exhibited stress fibres, broadened marginal filament bands and significantly more and larger cell-free areas in the monolayer, indicating incomplete cell–substrate binding. Remarkably, a functional confluent monolayer formation could only be achieved in co-cultures; it did not develop with the sole supplementation of recombinant VEGF-A165 to the HUVEC monocultures (unpublished data). The study demonstrated the multifunctional potential of cPnBA in combination with aMO2 as a cellular cytokine release system, adapting their secretion to the demand of HUVEC. In this way, a functional confluent monolayer could be generated within 3 days. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2012 %J 13th Dresden Polymer Discussion and 8th Max Bergmann-Symposium %T Tailoring Polymer Networks for Biomedical Applications %U %X %0 journal article %@ %A Neffe, A.T., Scharnagl, N., Behl, M., Lendlein, A. %D 2012 %J BioTOPics : Journal of Biotechnology in Berlin-Brandenburg %P 8-10 %T Biomaterials in Regenerative Medicine %U %X meets application-motivated science aiming at translation of the gained knowledge into products and clinical applications. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2012 %J Faszination Chemie, Kunststoffe - gestern - heute - morgen, Baekelandtag 2012 %T Polymernetzwerke als Grundlage molekularer Architekturen fuer multifunktionale Materialien %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2012 %J 4th International Conference on Smart Materials, Structures and Systems, CIMTEC 2012 %T Multifunctional Shape-Memory Polymer %U %X %0 conference lecture (invited) %@ %A Niendorf, T., Lendlein, A. %D 2012 %J BMBF Wissenschaftsdialog Medizintechnik %T Medizintechnik: Schwerpunkt Bildgebung - Aus Wissenschaft wird Wirtschaft %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2012 %J German-Russian Conference on Fundamentals and Applications of Nanoscience %T Magnetically induced Shape-memory Effect of Nanocomposites %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2012 %J Signing Ceremony for the Regenerative Medicine Coalition (RMC) %T International Cooperation Programms of the Helmholtz Association in the field of Regenerative Medicine %U %X %0 conference lecture %@ %A Lendlein, A. %D 2012 %J 5. Treffpunkt Regenerative Medizin, BCRT %T Einbindung des BCRT in die Forschungsaktivitaeten der Helmholtz-Gemeinschaft %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2012 %J Advanced Macromolecular Systems Across the Length Scales, AMSALS 2012 %T Design Principles for Key Functions of Polymer-based Implant Materials %U %X %0 journal article %@ 0255-2701 %A De Bartolo, L., Lendlein, A., Hofmann, D., Bader, A., de Grey, A., Curcio, E., Drioli, E. %D 2012 %J Chemical Engineering and Processing %P 79-87 %R doi:10.1016/j.cep.2011.09.009 %T Bio-hybrid organs and tissues for patient therapy: A future vision for 2030 %U https://doi.org/10.1016/j.cep.2011.09.009 %X This position paper gives a future vision for 2030 of the biohybrid organs and tissues that will be used for patient therapy and in the overcoming the age-related pathologies. The research strategies for the next 20 years will focus on the implantation of bioartificial tissues and the induction of the regeneration. Biomaterials and bioreactor technologies will play pivotal roles in the regeneration and in the production of individualized biological implants. Future challenges will include the development of multifunctional biohybrid organs and tissues. These concepts are based on a multidisciplinary approach bringing together various scientific fields, which will contribute to the new and fascinating medical therapies. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2012 %J Frontiers of Smart Polymeric Biomaterials and their Applications, 425th Xiangshan Science Conference %T Advances in smart/shape-memory polymers for biomedical applications %U %X %0 conference poster %@ %A Behl, M., Razzaq, M., Lendlein, A. %D 2012 %J Fachgruppentagung der GDCH Fachgruppe Makromolekulare Chemie - Smart Polymers %T Thermo-mechanical Characterization of Nanocomposites based on Oligo(Omega-pentadecalactone) and Magnetite Nanoparticles %U %X %0 lecture %@ %A Roch, T., Ma, N., Lendlein, A. %D 2012 %J %T Polymere als Biomaterialien %U %X %0 conference lecture (invited) %@ %A Neffe, A.T., Lendlein, A. %D 2012 %J Improving Health for the Ageing Society, Dialogue Forum %T Biomaterials for Regenerative Medicine %U %X %0 conference poster %@ %A Behl, M., Zotzmann, J., Lendlein, A. %D 2012 %J 9th World Biomaterial Congress %T Copolymer Networks with Triple-shape Capability %U %X %0 conference poster %@ %A Julich-Gruner, K.K., Neffe, A.T., Lendlein, A. %D 2012 %J Advanced Functional Polymers for Medicine, AFPM 2012 %T Synthesis and characterization of oligo(ethylene glycol)s functionalized with desaminotyrosine or desaminotyrosyltyrosine %U %X %0 conference lecture %@ %A Mathew, S., Roch, T., Frentsch, M., Wischke, C., Lendlein, A. %D 2012 %J Advanced Functional Polymers for Medicine, AFPM 2012 %T Adjuvant effect of microencapsulated NOD ligands studied in a human phagocytic cell line %U %X %0 conference lecture %@ %A Behl, M., Feng, Y., Lendlein, A. %D 2012 %J 4th International Conference on Smart Materials, Structures and Systems, CIMTEC 2012 %T Biocompatible, Degradable Multiblock Copolymers with Polydepsipeptide-segments and Shape-memory Properties %U %X %0 conference poster %@ %A Kumar, U.N., Kratz, K., Behl, M., Lendlein, A. %D 2012 %J German-Russian Conference on Fundamentals and Applications of Nanoscience %T Triple-shape Nanocomposites with Adaptable Apparent Switching Temperatures %U %X %0 conference poster %@ %A Kumar, U.N., Kratz, K., Noechel, U., Lendlein, A. %D 2012 %J Advanced Macromolecular Systems Across the Length Scales, AMSALS 2012 %T Shape-Memory Properties of Copolymer Networks Containing a Poly(ε-caprolactone) Crosslinker in an Aqueous Environment %U %X %0 conference poster %@ %A Pierce, B.F., Li, W., Scharnagl, N., Wischke, C., Sisson, A., Lendlein, A. %D 2012 %J Advanced Functional Polymers for Medicine, AFPM 2012 %T Influence of the co-monomer ratio on the physical properties and cytotoxicity of poly[acrylonitrile-co-(N-vinylpyrrolidone)]-based nanoparticles %U %X %0 conference lecture %@ %A Kratz, K., Heuchel, M., Lendlein, A. %D 2012 %J 9th World Biomaterials Congress %T Shape-memory polymer based active scaffolds with adjustable self-sufficiently moving capability %U %X %0 conference lecture %@ %A Kratz, K., Heuchel, M., Lendlein, A. %D 2012 %J 9th World Biomaterials Congress %T Non-contact activation of triple-shape effect in magneto-sensitive polymer network composites %U %X %0 conference lecture %@ %A Kratz, K., Lendlein, A. %D 2012 %J Intelligente Oberflaechen, Forschungspolitischer Dialog %T Cell- and Tissue Specific Polymer-Based Biomaterials %U %X %0 conference poster %@ %A Harmsen, D., Lendlein, A., Schroeter, M., Scheffler, P., Divinage, B. %D 2012 %J Tag der Chemie 2012 %T Experimente zu biologisch abbaubaren Polymeren - Hydrolytischer Abbau von Polymilchsaeure-Folie und Nachweis der Abbauprodukte %U %X %0 conference lecture %@ %A Lendlein, A. %D 2012 %J GDCh-Vortrag %T Memory Effect in Polymers and their Potential Applications in Medicine %U %X %0 conference lecture %@ %A Melchert, C., Behl, M., Lendlein, A. %D 2012 %J 4th International Conference on Smart Materials, Structures and Systems, CIMTEC 2012 %T Plasma treatment of LCE affects thermal properties of shape-changing materials %U %X %0 conference poster %@ %A Braune, S., Krueger, A., Kratz, K., Lendlein, A., Jung, F. %D 2012 %J 14th International Congress of Biorheology, 7th International Conference on Clinical Hemorheology %T Influence of randomized biomaterial micropatterning on platelet adhesion and activation %U %X %0 conference poster %@ %A Melchert, C., Yongvonsoontorn, N., Behl, M., Lendlein, A. %D 2012 %J Advanced Functional Polymers for Medicine, AFPM 2012 %T Synthesis and Characterization of Telechelic Oligoethers with Terminal Cinnamyliden Acetic Acid Moieties %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2012 %J Stevenson Biomaterials Lecture %T Designing Multifunctional Polymers for Medical Application %U %X %0 conference lecture %@ %A Lendlein, A. %D 2012 %J Schadensanalyse polymerbasierter Implantate als Basis fuer die wissensbasierte Biomaterialentwicklung, Workshop %T Einfuehrung in das Thema Schadensanalyse %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2012 %J 1st Cooperation Workshop of Sino-German Innovation Platform Life Sciences %T Sino-German Joint Laboratory for Materials in Regenerative Medicine %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2012 %J Cluster Gesundheitswirtschaft Health Capital – Die Chancen wahrnehmen %T Das Berlin-Brandenburger Centrum fuer Regenerative Therapien als Beispiel fuer Technologie-orientierte Ansaetze in der Medizin %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2012 %J 8th International Symposium on Stimuli-Responsive Materials %T Multifunctional Shape-Memory Polymers %U %X %0 conference lecture %@ %A Melchert, C., Yongvongsoontorn, N., Behl, M., Lendlein, A. %D 2012 %J Polydays 2012 %T Synthesis and Characterization of Telechelic Oligoethers with Terminal Cinnamyliden Acetic Acid Moieties %U %X %0 conference lecture %@ %A Behl, M., Zotzmann, J., Lendlein, A. %D 2012 %J 24th International Liquid Crystal Conference, ILCC 2012 %T Dual and Triple-Shape Properties of Poly(Omega-pentadecalactone)-based Polymer Networks %U %X %0 conference lecture %@ %A Lendlein, A., Behl, M., Kratz, K. %D 2012 %J 24th International Liquid Crystal Conference, ILCC 2012 %T Multifunctional Shape-Memory Polymers %U %X %0 conference lecture %@ %A Kratz, K., Lendlein, A. %D 2012 %J Materials Science and Engineering, MSE 2012 %T Processing of Biomaterials %U %X %0 conference lecture %@ %A Neffe, A.T., Pierce, B.F., Lendlein, A. %D 2012 %J 39th Congress of the European Society for Artificial Organs, ESAO 2012 %T Control of Mechanical Properties in Biopolymer-Based Biomaterials %U %X %0 conference lecture (invited) %@ %A Lendlein, A., Wischke, C. %D 2012 %J 2nd Symposium on Innovative Polymers for Controlled Delivery, SIPCD 2012 %T Multifunctional Polymer-based Drug Delivery Systems %U %X %0 conference lecture %@ %A Krueger, A., Roch, T., Ma, N., Lendlein, A. %D 2012 %J BSRT International Summer School of Innovative Approaches in Regenerative Medicine %T Hemocompatibility of Biomaterials/cPnBA %U %X %0 conference paper %@ %A Melchert, C., Behl, M., Lendlein, A. %D 2012 %J MRS Symposium Proceedings, Multifunctional Polymer-Based Materials, 2011 MRS Fall Meeting %P 119-124 %T Phase Transition Behavior of Main Chain Nematic Liquid-Crystalline Polymers Based on 2-methyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone and 2-tert-butyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone %U %X %0 conference paper %@ %A Tripodo, G., Wischke, C., Lendlein, A. %D 2012 %J MRS Symposium Proceedings, Multifunctional Polymer-Based Materials, 2011 MRS Fall Meeting %P 21-28 %T Design of semi-interpenetrating networks based on poly(ethyl-2-cyanoacrylate) and oligo(ethyleneglycol) diglycidyl ether %U %X %0 conference paper %@ %A Neffe, A.T., Pierce, B.F., Blaszkiewicz, J., Lendlein, A. %D 2012 %J MRS Symposium Proceedings, Multifunctional Polymer-Based Materials, 2011 MRS Fall Meeting %P 145-150 %T Quantifying Protein Adsorption to Physically Crosslinked Gelatin-Based Networks %U %X %0 conference paper %@ %A Wischke, C., Steuer, S., Lendlein, A. %D 2012 %J MRS Symposium Proceedings, Multifunctional Polymer-Based Materials, 2011 MRS Fall Meeting %P 207-212 %T Determining loading kinetics of drug releasing degradable shape-memory polymers %U %X %0 conference paper %@ %A Sauter, T., Kratz, K., Lendlein, A. %D 2012 %J MRS Symposium Proceedings, Multifunctional Polymer-Based Materials, 2011 MRS Fall Meeting %P 105-112 %T Shape-Memory Properties of Electrospun Non-wovens Prepared from Amorphous Polyetherurethanes Under Stress-free and Constant Strain Conditions %U %X %0 conference paper %@ %A Zotzmann, J., Behl, M., Lendlein, A. %D 2012 %J MRS Symposium Proceedings, Multifunctional Polymer-Based Materials, 2011 MRS Fall Meeting %P 85-90 %T Triple-Shape Effect of Copolymer Networks Based on Poly(Omega-pentadecalactone) and Poly(Epsilon-caprolactone) Segments Applying a Programming Procedure with an Adjusted Temperature Profile %U %X %0 conference paper %@ %A Piece, B.F., Neffe, A.T., Lendlein, A. %D 2012 %J MRS Symposium Proceedings, Multifunctional Polymer-Based Materials, 2011 MRS Fall Meeting %P 159-165 %T Using Mass Spectrometry to Investigate the Structural Features of Photocrosslinked Co-Networks based on Gelatin and Poly(ethylene glycol) Methacrylates %U %X %0 conference lecture %@ %A Jung, F., Lendlein, A. %D 2012 %J Biologisierung der Medizintechnik - Evolution oder Revolution? Strategieworkshop %T Biofunktionale Materialsysteme fuer die Medizintechnik %U %X %0 conference lecture %@ %A Braune, S., Krueger, A., Walter, M., Schiemann, M., Kratz, K., Kuepper, J.-H., Jung, F., Lendlein, A. %D 2012 %J 39th Congress of the European Society for Artificial Organs, ESAO 2012 %T Influence of different surface treatment of poly(n-butyl acrylate) networks on L929 mouse fibroblasts adhesion and viability %U %X %0 conference lecture %@ %A Behl, M., Feng, Y., Lendlein, A. %D 2012 %J 9th World Biomaterials Congress %T Degradable Multiblock Shape-Memory Copolymers Having Polydepsipeptide- and Poly(ε-caprolactone)segments as Biomaterials %U %X %0 conference lecture %@ %A Behl, M., Lendlein, A., Wischke, C. %D 2012 %J 9th World Biomaterials Congress %T Triple-functional polymer-based biomaterials combining controlled drug release, degradability and shape-memory capability %U %X %0 journal article %@ 2280-8000 %A Ghobadi, E., Heuchel, M., Kratz, K., Lendlein, A. %D 2012 %J Journal of Applied Biomaterials & Functional Materials %N 3 %P 293-301 %R doi:10.5301/JABFM.2012.10432 %T Simulation of volumetric swelling of degradable poly[(rac-lactide)-co-glycolide] based polyesterurethanes containing different urethane-linkers %U https://doi.org/10.5301/JABFM.2012.10432 3 %X The hydrolytic degradation behavior of degradable aliphatic polyester-based polymers is strongly influenced by the up-take or transport of water into the polymer matrix and also the hydrolysis rate of ester bonds.
Methods: We examined the volumetric swelling behavior of poly[(rac-lactide)-co-glycolide] (PLGA) and PLGA-based polyurethanes (PLGA-PU) with water contents of 0 wt%, 2 wt% and 7 wt% water at 310 K using a molecular modeling approach. Polymer systems with a number average molecular weight of Mn = 10,126 g∙mol-1 were constructed from PLGA with a lactide content of 67 mol%, whereby PLGA-PU systems were composed of five PLGA segments with Mn = 2052 g∙mol-1, which were connected via urethane linkers originated from 2,2,4–trimethyl hexamethylene-1,6-diisocyanate (TMDI), hexamethyl-1,6–diisocyanate (HDI), or L-lysine-1,6–diisocyanate (LDI).
Results: The calculated densities of the dry PLGA-PU systems were found to be lower than for pure PLGA. The obtained volumetric swelling of the PLGA-PU was depending on the type of urethane linker, whereby all swollen PLGA-PUs contained larger free volume distribution compared to pure PLGA. The mean square displacement curves for dry PLGA and PLGA-PUs showed that urethane linker units reduce the mobility of the polymer chains, while an increase in backbone atoms mobility was found, when water was added to these systems. Consequently, an increased water uptake of PLGA-PU matrices combined with a higher mobility of the chain segments should result in an accelerated hydrolytic chain scission rate in comparison to PLGA. Conclusions: It can be anticipated that the incorporation of urethane linkers might be a helpful tool to adjust the degradation behavior of polyesters. %0 journal article %@ 2280-8000 %A Ghobadi, E., Heuchel, M., Kratz, K., Lendlein, A. %D 2012 %J Journal of Applied Biomaterials & Functional Materials %N 3 %P 259-264 %R doi:10.5301/JABFM.2012.10440 %T Influence of different heating regimes on the shape-recovery behavior of poly(L-lactide) in simulated thermomechanical tests %U https://doi.org/10.5301/JABFM.2012.10440 3 %X Multifunctional polymer-based biomaterials, which combine degradability with a shape-memory capability and in this way enable the design of actively moving implants such as self-anchoring implants or controlled release systems, have been recently introduced. Of particular interest are approved degradable polymers such as poly(L-lactide) (PLLA), which can be easily functionalized with a shape-memory effect. In the case of semicrystalline PLLA, the glass transition can be utilized as shape-memory switching domain.
Methods: In this work we applied a fully atomistic molecular dynamics simulation to study the shape-memory behavior of PLLA. A heating-deformation-cooling programming procedure was applied to atomistic PLLA packing models followed by a recovery module under stress-free conditions allowing the shape recovery. The recovery was simulated by heating the samples from Tlow = 250 K to Thigh = 500 K with different heating rates β of 125, 40 and 4 K⋅ns-1. 
Results: We could demonstrate that the obtained strain recovery rate (Rr) was strongly influenced by the applied simulation time and heating rate, whereby Rr values in the range from 46% to 63% were achieved. On its own the application of a heating rate of 4 K⋅ns-1 enabled us to determine a characteristic switching temperature of Tsw = 473 K for the modeled samples. 
Conclusions: We anticipate that the atomistic modeling approach presented should be capable of enabling further study of Tsw with respect to the molecular structure of the investigated SMP and therefore could be applied in the context of design and development of new shape-memory (bio)materials. %0 conference lecture %@ %A Ma, N., Xu, X., Kratz, K., Li, Z., Roch, T., Jung, F., Lendlein, A. %D 2012 %J 14th International Congress of Biorheology, 7th International Conference on Clinical Hemorheology %T The influence of polymeric materials on mesenchymal stem cells cellular behaviors %U %X %0 conference lecture (invited) %@ %A Kratz, K., Heuchel, M., Razzaq, M., Lendlein, A. %D 2012 %J 8th European Solid Mechanics Conference, ESMC 2012 %T Heating and Stretching of Magneto-Sensitive and Mechanically Active Polymer Composites %U %X %0 lecture %@ %A Roch, T., Ma, N., Lendlein, A. %D 2012 %J %T Zellinteraktionen mit Polymeren fuer die regenerative Medizin %U %X %0 lecture %@ %A Roch, T., Krueger, A., Ma, N., Lendlein, A. %D 2012 %J %T Biocompatibility of Materials – Introduction into Biomaterial and Cyto-compatibility testing %U %X %0 lecture %@ %A Roch, T., Krueger, A., Ma, N., Lendlein, A. %D 2012 %J %T Immunocompatibility of biomaterials %U %X %0 conference poster %@ %A Tartivel, L., Behl, M., Schroeter, M., Lendlein, A. %D 2012 %J Advanced Functional Polymers for Medicine, AFPM 2012 %T Hydrogel Networks Based on ABA Triblock Copolymers %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2012 %J 1st International Symposium on Polymer Ecomaterials, PEM 2012 %T Tailoring Degradable Polymer Networks – From Design of Molecular Architecture to Multifunctional Degradable Biomaterials %U %X %0 conference lecture %@ %A Lendlein, A. %D 2012 %J Wissenschaft vor Ort, Das BCRT stellt sich vor %T Das Berlin-Brandenburger Centrum fuer Regenerative Therapien %U %X %0 conference lecture (invited) %@ %A Lendlein, A., Jung, F. %D 2012 %J Advanced Functional Polymers for Medicine, AFPM 2012 %T Biomaterials for Cardiovascular Applications - Challenges and Concepts %U %X %0 conference lecture %@ %A Lange, M., Luetzow, K., Neffe, A.T., Lendlein, A. %D 2012 %J Advanced Functional Polymers for Medicine, AFPM 2012 %T Characterization of Oligo(ethylene glycol) and Oligoglycerol functionalized Poly(ether imide) by Angle-dependent X-ray Photoelectron Spectroscopy %U %X %0 journal article %@ 1438-7492 %A Madbouly, S.A., Lendlein, A. %D 2012 %J Macromolecular Materials and Engineering %N 12 %P 1213-1224 %R doi:10.1002/mame.201200341 %T Degradable Polyurethane/Soy Protein Shape-Memory Polymer Blends Prepared Via Environmentally-Friendly Aqueous Dispersions %U https://doi.org/10.1002/mame.201200341 12 %X Degradable polyurethane/soybean protein (PU/SP) shape-memory polymer blends are synthesized using an environmentally-friendly aqueous dispersion technique. The effects of SP concentration on the blend miscibility, thermal properties, hydrolytic degradation, and shape-memory behavior are investigated. The shape recovery rates are found to depend on SP concentration. A porous structure can be generated using scCO2 foaming. This degradable blend may be an interesting multifunctional candidate material for potential biomedical applications. %0 journal article %@ %A Wischke, C., Kratz, K., Jung, F., Lendlein, A. %D 2012 %J BioTOPics : Journal of Biotechnology in Berlin-Brandenburg %P 5-7 %T Helmholtz Virtual Institute „Multifunctional Materials for Medicine“ %U %X into the regional cluster “Healthcare Industry Berlin-Brandenburg – Health Capital”. %0 journal article %@ 2040-3364 %A Razzaq, M.Y., Behl, M., Lendlein, A. %D 2012 %J Nanoscale %N 20 %P 6181-6195 %R doi:10.1039/c2nr31332d %T Memory-effects of magnetic nanocomposites %U https://doi.org/10.1039/c2nr31332d 20 %X The thermally induced shape memory effect (SME) is the capability of a material to fix a temporary (deformed) shape and recover a ‘memorized’ permanent shape in response to heat. SMEs in polymers have enabled a variety of applications including deployable space structures, biomedical devices, adaptive optical devices, smart dry adhesives and fasteners. By the incorporation of magnetic nanoparticles (mNP) into shape-memory polymer (SMP), a magnetically controlled SME has been realized. Magnetic actuation of nanocomposites enables remotely controlled devices based on SMP, which might be useful in medical technology, e.g. remotely controlled catheters or drug delivery systems. Here, an overview of the recent advances in the field of magnetic actuation of SMP is presented. Special emphasis is given on the magnetically controlled recovery of SMP with one switching temperature Tsw (dual-shape effect) or with two Tsws (triple-shape effect). The use of magnetic field to change the apparent switching temperature (Tsw,app) of the dual or triple-shape nanocomposites is described. Finally, the capability of magnetic nanocomposites to remember the magnetic field strength (H) initially used to deform the sample (magnetic-memory effect) is addressed. The distinguished advantages of magnetic heating over conventional heating methods make these multifunctional nanocomposites attractive candidates for in vivo applications. %0 journal article %@ 1946-4274 %A Razzaq, M.Y., Behl, M., Lendlein, A. %D 2012 %J MRS Online Proceedings Library %P 19-24 %R doi:10.1557/opl.2012.222 %T Shape-Memory Properties of Nanocomposites based on Poly(Omega-pentadecalactone) and Magnetic Nanoparticles %U https://doi.org/10.1557/opl.2012.222 %X Magneto-sensitive shape-memory polymers (SMP) obtained by incorporating magnetic nanoparticles in a SMP matrix are an emerging class of multifunctional materials. The incorporation of the nanoparticles enhanced the mechanical properties and in addition enabled remote actuation by exposure to alternating magnetic fields. Here, we report on the thermallyinduced shape-memory properties of such magneto-sensitive nanocomposites based on poly(ω- pentadecalactone) (PPDL) switching segments and magnetic nanoparticles. A series of nanocomposites were prepared by crosslinking of poly(ω-pentadecalactone)dimethacrylate (Mn = 2800 g·mol-1and 5100 g·mol-1) in the presence of silica encapsulated magnetic nanoparticles. The silica shell of the nanoparticles was selected to enhance the distribution and compatibility of the nanoparticles with the polymer matrix. Thermal and mechanical properties of the nanocomposites were explored as a function of PPDL chain length and nanoparticle weight content. All nanocomposites exhibited excellent shape-memory properties with shape fixity rates between 86% and 93% and shape recovery rates above 97%. Potential applications for such shape-memory nanocomposites include smart implants, medical instruments, which could be controlled on demand by thermal or indirect magnetic heating. %0 journal article %@ 2280-8000 %A Li, W., Pierce, B.F, Scharnagl, N., Wischke, C., Sisson, A.L., Lendlein, A. %D 2012 %J Journal of Applied Biomaterials & Functional Materials %N 3 %P 308-314 %R doi:10.5301/jabfm.2012.10430 %T Influence of co-monomer ratio on the chemical properties and cytotoxicity of poly[acrylonitrile-co-(N-vinylpyrrolidone)] nanoparticles %U https://doi.org/10.5301/jabfm.2012.10430 3 %X Purpose. A system of nanoparticles with varying hydrophilicities may include promising biomaterial candidates as they offer various cellular uptake properties and a range of drug encapsulation efficacies, which would be advantageous in regenerative therapies. Therefore, a model system of nanoparticles with varying hydrophilicities was synthesized and assessed for its candidacy as a biomaterial.Methods. Here, acrylonitrile (AN) was copolymerized with N-vinylpyrrolidone (NVP) in a mini-emulsion to form a family of nanoparticles, thereby enabling the systematic variation of the copolymer hydrophilicity. The nanoparticles based on these copolymers were prepared and characterized using 1H-NMR, dynamic light scattering, differential scanning calorimetry, and thermal gravimetric analysis. Finally, the cytotoxicity of the nanoparticles was assessed by conducting indirect tests using L929 fibroblasts.
Results. The nanoparticles showed well controlled NVP/AN molar ratios as determined by 1H NMR, well defined diameters ranging from approximately 100 nm to 200 nm, and increasing glass transition temperatures with increasing molar NVP content. Finally, L929 fibroblasts only slightly changed their morphology upon incubation with material eluates.
Conclusions. Poly[acrylonitrile-co-(N-vinylpyrrolidone)] nanoparticles with varying amounts of NVP were shown to be a promising model system for further biological assessment. %0 conference poster %@ %A Scharnagl, N., Hiebl, B., Trescher, K., Zierke, M., Behl, M., Kratz, K., Jung, F., Lendlein, A. %D 2012 %J 31. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Behaviour of fibroblasts on water born acrylonitrile based copolymers with different densities of positive and negative surface charges %U %X %0 conference lecture %@ %A Behl, M., Ridder, U., Kelch, S., Lendlein, A. %D 2012 %J 9th World Biomaterials Congress %T Blending of Degradable Multiblock Copolymers creates Shape- Memory Materials %U %X %0 journal article %@ 2280-8000 %A Lange, M., Luetzow, K., Neffe, A.T., Lendlein, A. %D 2012 %J Journal of Applied Biomaterials & Functional Materials %N 3 %P 215-222 %R doi:10.5301/JABFM.2012.10345 %T Characterization of Oligo(ethylene glycol) and Oligoglycerol functionalized Poly(ether imide) by Angle-dependent X-ray Photoelectron Spectroscopy %U https://doi.org/10.5301/JABFM.2012.10345 3 %X Purpose: Previous investigations have shown that poly(ether imide) (PEI) membranes can be functionalized with aminated macromolecules. In this study we explored whether the characterization of PEI functionalized with oligo(ethylene glycol) (OEG) or linear, side chain methylated oligoglycerols (OGMe), by angle-dependent X-ray induced photoelectron spectroscopy (XPS) can be used to prove the functionalization, give insight into the reaction mechanism and reveal the spatial distribution of the grafts. 
Methods: PEI membranes were functionalized under alkaline conditions using an aqueous solution with 2 wt% of α-amino-ω-methoxy oligo(ethylene glycol) (Mn = 1,320 g·mol-1) or linear, side chain methylated monoamine oligoglycerols (Mn = 1,120, 1,800 or 2,270 g·mol-1), respectively. The functionalized membranes were investigated using XPS measurements at different detector angles to enable comparison between the signals related to the bulk and surface volume and were compared with untreated and alkaline-treated PEI membranes.
 Results: While at a perpendicular detector angle the bulk signals of the PEI were prominent, at larger surface volume-related detector angles, the signals for OGMe and OEG were determinable. 
Conclusion: The surface functionalization of PEI with OEG and OGMe could be verified by the angle-dependent XPS. The observations proved the functionalization at the PEI surface, as the polyethers were detected at angles providing signals of the surface volume. Furthermore, the chemical functions determined verified a covalent binding via the nucleophilic addition of the amine functionalized OGMe and OEG to the PEI imide function. %0 journal article %@ 2280-8000 %A Melchert, C., Yongvongsoontorn, N., Behl, M., Lendlein, A. %D 2012 %J Journal of Applied Biomaterials & Functional Materials %N 3 %P 185-190 %R doi:10.5301/JABFM.2012.10364 %T Synthesis and characterization of telechelic oligoethers with terminal cinnamylidene acetic acid moieties %U https://doi.org/10.5301/JABFM.2012.10364 3 %X Purpose: The formation of photoresponsive hydrogels were reported by irradiation of star-shaped poly(ethylene glycol)s with terminal cinnamylidene acetic acid (CAA) groups, which are capable of a photoinduced [2+2] cycloaddition. In this study we explored whether oligo(ethylene glycol)s and oligo(propylene glycol)s of varying molecular architecture (linear or star-shaped) or molecular weights could be functionalized with CAA as terminal groups by esterification or by amide formation.
Methods: Oligo(ethylene glycol) (OEG) and oligo(propylene glycol) (OPG) with varying molecular architecture (linear, star-shaped) and weight average molecular weights between 1000 and 5000 g.mol-1 were functionalized by means of esterification of hydroxyl or amine endgroups with cinnamylidene acetic acid (CAA) or cinnamylidene acetyl chloride (CAC) as telechelic endgroups. The chemical structure, thermal properties, and molecular weights of the oligoethers obtained were determined by NMR spectroscopy, UV spectroscopy, DSC, and MALDI-TOF.
Results: CAA-functionalized linear and star-shaped OEGs or OPGs could be obtained with a degree of functionalization higher than 90%. In MALDI-TOF measurements an increase in Mw of about 150 g∙mol-1 (for each terminal end) after the functionalization reaction was observed. OEGCAA and OPGCAA showed an increase in glass transition temperature (Tg) from about -70°C to -50°C, compared to the unfunctionalized oligoethers. In addition, the melting temperature (Tm ) of OEGCAA decreased from about 55°C to 30°C, which can be accounted for by the hampered crystallization of the precursors because of the bulky CAA end groups as well as by the loss of the hydroxyl telechelic end groups.
Conclusion: The synthesis of photoresponsive oligoethers containing cinnamylidene acetic acid as telechelic endgroup was reported and high degrees of functionalization could be achieved. Such photosensitive oligomers are promising candidates as reactive precursors, for the preparation of biocompatible high molecular weight polymers and polymer networks. %0 conference lecture %@ %A Balk, M., Behl, M., Noechel, U., Lendlein, A. %D 2012 %J 4th International Conference on Smart Materials, Structures and Systems, CIMTEC 2012 %T Shape-Memory Hydrogels with Switching Segments Based on Oligo(Omega-pentadecalactone) %U %X %0 conference poster %@ %A Friess, F., Wischke, C., Behl, M., Lendlein, A. %D 2012 %J Advanced Functional Polymers for Medicine, AFPM 2012 %T Oligo(Epsilon-caprolactone)-based polymer networks prepared by photocrosslinking in solution %U %X %0 journal article %@ 0268-3555 %A Hiebl, B., Mueller, C., Goers, J., Jung, F., Lendlein, A., Juenger, M., Hamm, B., Niehues, S.M. %D 2012 %J Phlebology %N 7 %P 337-346 %R doi:10.1258/phleb.2011.011035 %T A NiTi alloy-based cuff for external banding valvuloplasty: a six-week follow-up study in pigs %U https://doi.org/10.1258/phleb.2011.011035 7 %X Conclusion A foreign body response resulted in a fibrous capsule covering the cuff which might limit cuff functionality. %0 conference poster %@ %A Sauter, T., Kratz, K., Lendlein, A. %D 2012 %J Materials Science and Engineering, MSE 2012 %T Shape-Memory Properties of Electrospun Non-Wovens %U %X %0 journal article %@ 2280-8000 %A Tartivel, L., Behl, M., Schroeter, M., Lendlein, A. %D 2012 %J Journal of Applied Biomaterials & Functional Materials %N 3 %P 243-248 %R doi:10.5301/JABFM.2012.10295 %T Hydrogel networks based on ABA triblock copolymers %U https://doi.org/10.5301/JABFM.2012.10295 3 %X Background: Triblock copolymers from hydrophilic oligo(ethylene glycol) segment A and oligo(propylene glycol) segment B, providing an ABA structure (OEG-OPG-OEG triblock), are known to be biocompatible and are used as self-solidifying gels in drug depots. A complete removal of these depots would be helpful in cases of undesired side effects of a drug, but this remains a challenge as they liquefy below their transition temperature. Therefore we describe the synthesis of covalently cross-linked hydrogel networks. Method: Triblock copolymer-based hydrogels were created by irradiating aqueous solutions of the corresponding macro-dimethacrylates with UV light. The degree of swelling, swelling kinetics, mechanical properties and morphology of the networks were investigated. Results: Depending on precursor concentration, equilibrium degree of swelling of the films ranged between 500% and 880% and was reached in 1 hour. In addition, values for storage and loss moduli of the hydrogel networks were in the 100 Pa to 10 kPa range. Conclusion: Although OEG-OPG-OEG triblocks are known for their micellization, which could hamper polymer network formation, reactive OEG-OPG-OEG triblock oligomers could be successfully polymerized into hydrogel networks. The degree of swelling of these hydrogels depends on their molecular weight and on the oligomer concentration used for hydrogel preparation. In combination with the temperature sensitivity of the ABA triblock copolymers, it is assumed that such hydrogels might be beneficial for future medical applications – e.g., removable drug release systems. %0 journal article %@ 2280-8000 %A Julich-Gruner, K.K., Neffe, A.T., Lendlein, A. %D 2012 %J Journal of Applied Biomaterials & Functional Materials %N 3 %P 170-176 %R doi:10.5301/JABFM.2012.10342 %T Synthesis and characterization of oligo(ethylene glycol)s functionalized with desaminotyrosine or desaminotyrosyltyrosine %U https://doi.org/10.5301/JABFM.2012.10342 3 %X Purpose: The aromatic compounds desaminotyrosine (DAT) and desaminotyrosyltyrosine (DATT) have been successfully used to functionalize gelatin in order to form physically crosslinked networks via π-π interactions and hydrogen bonds of the introduced phenol moieties. Here, it was explored whether this concept can be applied to a synthetic polymer not engaging in additional interactions such as triple helix formation in gelatin, enabling a network to form by physical interactions mainly related to the terminal functional groups. Oligo(ethylene glycol) (OEG) was chosen as hydrophilic synthetic polymer for the backbone structure. Methods: Linear OEG (MP = 3 kDa) and four-arm OEG (Mn = 5 kDa) with amino functionalities as endgroups were functionalized with DAT and DATT using EDC·HCl and NHS as activating agents. The compounds were characterized by NMR, IR spectroscopy, and MALDI. Rheological behavior of aqueous solutions of the polymers was studied. The critical micelle concentration (CMC) was determined by a fluorescence spectroscopic analysis using the hydrophobic fluorescent dye pyrene. Results: DATT-functionalized linear OEG, four-arm DAT-functionalized OEG and four-arm DATT-functionalized OEG were synthesized with degrees of functionalization of 60-95 mol%. All compounds were water soluble, and rheological measurements revealed a decrease in storage modulus G’ and loss modulus G’’ compared to unfunctionalized OEG. Moreover, the CMC of linear OEG-DATT could be determined. Conclusions: The syntheses of OEG functionalized with the aromatic compounds DAT and DATT was reported. The polymers showed the properties of a surfactant. %0 conference poster %@ %A Noechel, U., Kratz, K., Behl, M., Zizak, I., Lendlein, A. %D 2012 %J Advanced Macromolecular Systems Across the Length Scales, AMSALS 2012 %T Nanostructural Changes of Temperature-Memory Polymers With Crystallizable Controlling Units Explored by SAXS/WAXS %U %X %0 conference poster %@ %A Neffe, A.T., Santan, H.D., Kamlage, S., Lendlein, A. %D 2012 %J GDCh Biannual Meeting of the GDCh-Division Macromolecular Chemistry, Smart Polymers %T Thermal Gelation and Stability of Pectin and Chondroitin Sulfate Grafted with Poly(ethylene glycol-b-propylene glycol-b-ethylene glycol) %U %X %0 conference poster %@ %A Neffe, A.T., Zaupa, A., Pierce, B.F., Roch, T., Jung, F., Lendlein, A. %D 2012 %J COST Namabio 2nd Joint Meeting %T Functionalization of Gelatin with Tyrosine Moieties: A Supramolecular Approach to Biomaterials %U %X %0 conference paper %@ %A Razzaq, M.Y., Behl, M., Lendlein, A. %D 2012 %J MRS Symposium Proceedings, Multifunctional Polymer-Based Materials, 2011 MRS Fall Meeting %P 3-8 %T Shape-Memory Properties of Nanocomposites based on Poly(Omega-pentadecalactone) and Magnetic Nanoparticles %U %X %0 journal article %@ 1438-7492 %A Balk, M., Behl, M., Nöchel, U., Lendlein, A. %D 2012 %J Macromolecular Materials and Engineering %N 12 %P 1184-1192 %R doi:10.1002/mame.201200232 %T Shape-Memory Hydrogels with Switching Segments Based on Oligo(ω-pentadecalactone) %U https://doi.org/10.1002/mame.201200232 12 %X We investigated whether dual-shape hydrogels based on crosslinked N-vinyl-2-pyrrolidone can be created, in which oligo(ω-pentadecalactone) (equation image = 2900 g · mol−1, Tm = 89 °C) chain segments contribute to the switching domains. In the obtained hydrogels, the volumetric degree of swelling decreased from 480 to 190% while the E-moduli increased from 0.10 to 0.34 MPa with increasing OPDL content. Furthermore, the equilibrium swollen hydrogels displayed good shape-memory properties with strain fixity ratios above 95% and strain recovery rates above 92%. These shape-memory hydrogels, whose degree of swelling was almost independent of the temperature, might be interesting candidates for various applications such as stimuli-sensitive switches or valves. %0 conference paper %@ %A Santan, H.D., Neffe, A.T., Kamlage, S., Lendlein, A. %D 2012 %J MRS Symposium Proceedings, Multifunctional Polymer-Based Materials, 2011 MRS Fall Meeting %P 151-158 %T Thermal Gelation and Stability of Pectin Grafted with PEPE %U %X %0 editorial %@ 1742-7061 %A Lendlein, A., Pierce, B.F., Ambrosio, L., Grijpma, D. %D 2012 %J Acta Biomaterialia %N 12 %P 4199-4199 %R doi:10.1016/j.actbio.2012.09.036 %T Advanced functional polymers for medicine: Multifunctional biomaterials %U https://doi.org/10.1016/j.actbio.2012.09.036 12 %X %0 journal article %@ 1946-4274 %A Kratz, K., Kumar, U., Noechel, U., Lendlein, A. %D 2012 %J MRS Online Proceedings Library %P 7-12 %R doi:10.1557/opl.2012.454 %T Thermal Properties and Crystallinity of Grafted Copolymer Networks containing a Crystallizable Poly(ε-caprolactone) Crosslinker in an aqueous environment %U https://doi.org/10.1557/opl.2012.454 %X The water swelling capability of the CLEG polymer networks was found to increase from 120% to 240% with increasing weight content of PEG. In contrast to the dry state, where two well separated melting temperatures could be observed for all CLEG samples, in aqueous environment only one melting temperature slightly above 40 °C, was obtained, whereby the overall crystallinity after swelling with water was strongly related to the PCL content in the CLEG polymer networks. %0 conference lecture (invited) %@ %A Rueder, C., Sauter, T., Kratz, K., Peter, J., Jung, F., Lendlein, A., Zohlnhoefer, D. %D 2012 %J 31. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Smooth muscle and endothelial cell behaviour on polymeric films with different chemical compositions %U %X %0 journal article %@ 1381-5148 %A Kaiser, C., Behl, M., Schroeter, M., Kratz, K., Lendlein, A. %D 2012 %J Reactive and Functional Polymers %N 8 %P 533-541 %R doi:10.1016/j.reactfunctpolym.2012.04.015 %T Dicarboxy-telechelic cooligomers with sequence structure tunable light absorption %U https://doi.org/10.1016/j.reactfunctpolym.2012.04.015 8 %X Alternating cooligomers of 5 pyrrole (P) and thiophene (T) units with a PTPTP sequence and carboxylic telechelic groups in α,α′-position are supposed to provide a low band gap and might be incorporated into degradable polymers. In this study we explored whether such new α,α′-ester linked π-conjugated alternating electron rich PTPTP cooligomers of defined size could be created following a Stille coupling synthesis pathway. The obtained cooligomers displayed in the absorption spectra λmax between 341 and 379 nm in solution and between 346 and 410 nm in the solid state, which could be tuned by the substitution with donor type alkyl and alkoxy functions. A strong red shift of the absorption bands into the IR region of the spectrum with absorption maxima between 550 and 650 nm and further to 850 and 1000 nm could be obtained when additional charges by deprotonation or oxidation were introduced. The prepared semi conducting materials could be applied potentially as dyes for photoacoustic imaging or in sensors for oxidation monitoring. %0 journal article %@ 2280-8000 %A Wang, L., Heuchel, M., Fang, L., Kratz, K., Lendlein, A. %D 2012 %J Journal of Applied Biomaterials & Functional Materials %N 3 %P 203-209 %R doi:10.5301/JABFM.2012.10293 %T Influence of a polyester coating of magnetic nanoparticles on magnetic heating behavior of shape-memory polymer-based composites %U https://doi.org/10.5301/JABFM.2012.10293 3 %X Background: Magnetic composites of thermosensitive shape-memory polymers (SMPs) and magnetite nanoparticles (MNPs) allow noncontact actuation of the shape-memory effect in an alternating magnetic field. In this study, we investigated whether the magnetic heating capability of cross-linked poly(ε-caprolactone)/MNP composites (cPCLC) could be improved by covalent coating of MNPs with oligo(ε-caprolactone) (OCL). Methods: Two different types of cPCLC containing uncoated and OCL-coated MNP with identical magnetite weight content were prepared by thermally induced polymerization of poly(ε-caprolactone) diisocyanatoethyl methacrylate. Both cPCLCs exhibited a melting transition at Tm = 48°C, which could be used as switching transition. Results: The dispersion of the embedded nanoparticles within the polymer matrix could be substantially improved, when the OCL-coated MNPs were used, as visualized by scanning electron microscopy. We could further demonstrate that in this way the maximal achievable bulk temperature (Tbulk) obtained within the cPCLC test specimen in magnetic heating experiments at a magnetic field strength of H = 30 kA⋅m-1 could be increased from Tbulk = 48°C to Tbulk = 74°C. %0 conference lecture %@ %A Razzaq, M.Y., Behl, M., Lendlein, A. %D 2012 %J 4th International Conference on Smart Materials, Structures and Systems, CIMTEC 2012 %T Memory Effects in Magnetic Nanocomposites %U %X %0 conference lecture %@ %A Wischke, C., Lendlein, A. %D 2012 %J 5. Treffpunkt Regenerative Medizin %T Forschungsfeld B - Polymerbasierte Biomaterialien %U %X %0 journal article %@ 1946-4274 %A Yang, K.K., Zotzmann, J., Lendlein, A., Behl, M. %D 2012 %J MRS Online Proceedings Library %P 190-195 %R doi:10.1557/opl.2012.453 %T Synthesis and Characterization of Hydroxy-telechelic Four-arm Star-shaped Oligo(tetrahydrofuran), Their Crosslinking, and Thermomechanical Investigation of the Poymer Network %U https://doi.org/10.1557/opl.2012.453 %X Here the synthesis of hydroxy-telechelic four-arm star-shaped oligotetrahydrofuran (4PTHF) with controllable molecular weight was explored, which was perfomed as living cationic ring-opening polymerization of THF using pentaerythritol and trifluoromethanesulfonicanhydride as initiation system. The molecular weights of the 4PTHF were a function of the reaction time. A polymer network was prepared from the hydroxy-telechelic 4PTHF precursor by crosslinking with diisocyanate and the shape-memory properties were determined. High values for Rf and Rr > 98% were obtained even at high programmed elongations, which suggest the 4PTHF-network as a promising shape-memory material. These materials might have a great potential, as the upscaling of synthesis could be successfully demonstrated. %0 conference lecture (invited) %@ %A Lendlein, A., Pierce, B.F., Neffe, A.T. %D 2012 %J 9th World Biomaterials Congress %T Knowledge-based design of degradable polymers %U %X %0 journal article %@ 2280-8000 %A Mathew, S., Roch, T., Frentsch, M., Lendlein, A., Wischke, C. %D 2012 %J Journal of Applied Biomaterials & Functional Materials %N 3 %P 229-236 %R doi:10.5301/JABFM.2012.10438 %T Adjuvant effect of microencapsulated NOD ligands studied in a human phagocytic cell line %U https://doi.org/10.5301/JABFM.2012.10438 3 %X Background: Modern subunit vaccines, which are of high purity compared with traditional vaccines, are often incapable of inducing strong immune responses as necessary to build an immunological memory. The desired level of immune response can be achieved only by codelivering immune-modulating agents along with the antigenic epitopes present in these high-purity formulations. This study aimed to explore the adjuvant effect of nucleotide oligomerization domain (NOD) receptor agonists as immunomodulators encapsulated in polymeric microparticles as carriers.
Methods: Microparticles (MP) prepared from poly[(rac-lactide)-co-glycolide] (PLGA) (Mn = 5 kDa, PD = 3.2) by the water-in-oil-in-water (w/o/w) emulsion/solvent evaporation technique were characterized in terms of size, surface morphology, payload and endotoxin content. As NOD agonists, N-acetylmuramyl–L-alanyl–D-isoglutamine (MDP; NOD 2) and γ-D-glutamyl-meso-diaminopimelic acid (iE-DAP; NOD 1) were encapsulated. The immunomodulatory potential of these ligand-loaded MP was evaluated with a human acute monocytic leukemia cell line (THP-1X Blue-CD14 cells). 
Results: The MP prepared had a phagocytosable size (<10 µm) with a unimodal size distribution and low endotoxin content (<0.5 EU/mL). A dose-dependent cell activation could be established for MDP-loaded microparticles.
Conclusions: MP with suitable characteristics for phagocytosis can be prepared and loaded with NOD agonists. The capability of these ligand-loaded microparticles to activate monocytes suggests their broader exploration as vaccine carriers. %0 journal article %@ 1946-4274 %A Yang, D., Feng, Y., Behl, M., Lendlein, A., Zhao, H., Khan, M., Guo, J. %D 2012 %J MRS Online Proceedings Library %P 220-225 %R doi:10.1557/opl.2012.702 %T Biomimetic Hemo-compatible Surfaces of Polyurethane by Grafting Copolymer Brushes of Poly(ethylene glycol) and Poly(phosphorylcholine methacrylate) %U https://doi.org/10.1557/opl.2012.702 %X Polyurethanes (PU) have been widely used as biomaterial in recent years, while thrombus may still occur when contacting with blood especially for extended period of time. Poly(ethylene glycol) (PEG) and phosphorylcholine (PC)-based polymers are commonly employed for surface modification to create protein repellent surfaces. PC-based polymers have been investigated as biomimetic materials because PC is the major component in the outer layer of cell membranes. In this study, the biomimetic copolymer brush of PEG-b-poly(2-methacryloyloxyethyl phosphorylcholine) on PU surfaces was synthesized via atom transfer radical polymerization (ATRP) with a surface initiator. The flexible PEG chain was 200 g·mol−1, while the poly(2-methacryloyloxyethyl phosphorylcholine) (poly(MPC)) chain length was controlled by the ratio of monomer to sacrificial initiator in solution. The topology of the modified surfaces was characterized by the phase image of atomic force microscopy (AFM) to study the synergy effect between PEG chains and poly(MPC) chains. The unmodified and modified surfaces were characterized by Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), water contact angle and platelet adhesion. The results demonstrated that efficient grafting of PEG-b-poly(MPC) brushes on the surfaces was achieved. The PU surfaces modified with PEG and phosphorylcholine zwitterionic brushes showed effective resistance to platelet adhesion and high hemocompatibility in vitro. These PEG and PC-grafted PU materials might be potentially applied in blood-contacting materials or devices due to their good mechanical and hemocompatible properties. %0 journal article %@ 1946-4274 %A Iqbal, D., Melchert, C., Behl, M., Lendlein, A., Beuermann, S. %D 2012 %J MRS Online Proceedings Library %P 1-6 %R doi:10.1557/opl.2012.423 %T Modeling of Free Radical Polymerization of Azobenzene-based Linear Polymers %U https://doi.org/10.1557/opl.2012.423 %X Modeling of free radical polymerizations of the liquid-crystalline monomer 6-[4-(4-heptyloxyphenylazo)phenoxy]hexylacrylate using the PREDICI software package is reported. The model accounts for all elemental reactions that were identified to be important for radical polymerizations of acrylate-type monomers. On the basis of butyl acrylate kinetic data a remarkable agreement between number average molar masses from modelling (Mn,sim) and from experiments (Mn,exp) is observed: Mn,sim = 17800 g·mol−1 and Mn,exp = 17400 g·mol−1. Similarly, dispersity values of 1.8 and 1.6 were determined via modelling and experiments, respectively. It is shown that the assumption of butyl acrylate kinetics provides a reasonable approximation even for acrylate-based monomers having mesogenic substituents. %0 journal article %@ 1946-4274 %A Schroeter, M., Behl, M., Weder, C., Lendlein, A. %D 2012 %J MRS Online Proceedings Library %P 183-188 %R doi:10.1557/opl.2012.424 %T Synthesis and Characterization of Poly(p-phenylene ethynylene)s with nitroxyl radical endgroups %U https://doi.org/10.1557/opl.2012.424 %X The generation of terminal N-Hydroxyl substituents in p-phenylene ethynylene based compounds is presented. P-phenylene ethynylene derivatives were synthesized in a Sonogashira coupling reaction. N-Hydroxyl groups could be introduced by lithiation of iodine moieties and subsequent reaction with the 2-methyl-2-nitrosopropane generated by the cleavage of its dimer. The synthesis by lithiation was found to be more effective compared to the reaction with the Grignard reagent and the chloro-derivative. The resulting compounds were characterized by 1H NMR, UV and PL spectroscopy and were shown to be sensitive towards oxidation. This new approach of introducing additional charge carriers by nitroxyl endgroups might enable conjugated polymers with enhanced conductivity. %0 report part %@ %A Lendlein, A., Bindseil, K.U. %D 2011 %J Technologiereport - Regenerative Medizin in Berlin-Brandenburg %P 9-10 %T Regenerative Medizin - Vorwort %U %X Der Report stellt sowohl die regionalen Forschungsschwerpunkte als auch Unternehmen vor und erläutert das regulatorische und politische Umfeld der Regenerativen Medizin. Er geht zudem auf die Rahmenbedingungen für die Entwicklung und Kommerzialisierung von entsprechenden Medizinprodukten und Pharmazeutika ein. %0 conference poster %@ %A Braune, S., Hoenow, A., Mrowietz, C., Lendlein, A., Jung, F. %D 2011 %J 16th International Conference of the European Society for Clinical Hemorheology and Microcirculation (ESCHM) and the 30th Annual Conference of the German Society for Clinical Microcirculation and Hemorheology (DGKMH) %T Thrombogenicity of Poly(n-butylacrylat) networks %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2011 %J ESAO-Winter School 2011 %T Technologie und Medizin %U %X %0 report part %@ %A Wischke, C., Lendlein, A. %D 2011 %J Technologiereport - Regenerative Medizin in Berlin-Brandenburg %N 3 %P 80-82 %T Systeme zur kontrollierten Wirkstofffreisetzung %U 3 %X %0 conference lecture %@ %A Lendlein, A. %D 2011 %J TechnologieTagTeltow %T Innovationsnukleus - Polymere fuer die Biomedizin %U %X %0 journal article %@ 1042-7147 %A Cui, J., Kratz, K., Hiebl, B., Jung, F., Lendlein, A. %D 2011 %J Polymers for Advanced Technologies %N 1 %P 126-132 %R doi:10.1002/pat.1816 %T Soft poly(Eta-butyl acrylate) networks with tailored mechanical properties designed as substrates for in vitro models %U https://doi.org/10.1002/pat.1816 1 %X Mechanical conditioning can serve as a potent tool to influence mechano-responsive cells, which plays a prominent role during formation and regeneration of functional tissue. Recently, the differentiation of mesenchymal stem cells could be influenced by the local stiffness of hydrogels used as 2D substrates. However, the mechanical properties and the swellability of hydrogels in physiological liquids are difficult to control precisely as their properties strongly depend on physical parameters like ionic strength or pH value. Here, we explored amorphous, hydrophobic poly(n-butyl acrylate) networks (cPnBA) as soft substrates for cell culture system with adjustable mechanical properties. cPnBAs were synthesized via bulk radical polymerization from n-butyl acrylate (nBA) and poly(propylene glycol) dimethacrylate (PPGDMA) as crosslinker. The Young's modulus for cPnBAs determined by tensile tests could be systematically adjusted from 100 kPa to 10 MPa by increasing the PPGDMA-content at ambient temperature, while the glass transition temperature (Tg) was found to increase from −46 to −22°C. All cPnBAs exhibited similar surface properties with a surface roughness (Rq) in the range from 1.4 to 0.4 µm and advancing contact angles from 115° to 100°, which remained constant after ethylene oxide sterilization. The extracts of sterilized materials were tested for cytotoxic effects with L929 cells. All tested samples were non-cytotoxic. The functional integrity of cell membranes and mitochondrial activity stayed unaffected. The investigated polymer networks are promising candidates as soft substrates for passive mechanical stimulation of cells in vitro in cell culture devices or in vivo as implant coatings. %0 conference poster %@ %A Tripodo, G., Wischke, C., Neffe, A.T., Lendlein, A. %D 2011 %J Advanced Functional Polymers for Medicine, AFPM 2011 %T Highly elastic poly(ethyl-2-cyanoacrylate) based materials obtained by incorporation of oligo(ethylene glycol) diglycidyl ether as a softener %U %X %0 book part %@ %A Behl, M., Lendlein, A. %D 2011 %J Kirk-Othmer Encyclopedia of Chemical Technology %P 1-16 %R doi:10.1002/0471238961.1908011612051404.a01.pub2 %T Shape-Memory Polymers %U https://doi.org/10.1002/0471238961.1908011612051404.a01.pub2 %X Shape-memory polymers (SMP) are an emerging class of active materials, which are able to change their shape in a predefined way upon appropriate stimulation. SMP, which can switch from a temporary to their permanent shape, are dual-shape materials. Here fundamental aspects concerning the design of suitable polymer architectures as well as of tailored programming processes are presented. Furthermore, the influence of various physical parameters on the shape recovery is discussed. Shape-memory research initially was focused on the thermally induced dual shape-effect. Presently, this research field is rapidly developing in two major areas. On the one hand other stimuli are being realized by either indirect thermal actuation or direct actuation by addressing stimuli-sensitive groups on the molecular level. On the other hand the programmed shape changes are getting more complex. Triple-shape materials are able to perform two subsequent on-demand shape changes and multishape materials are extending this to even more steps. %0 report part %@ %A Lendlein, A. %D 2011 %J Technologiereport - Regenerative Medizin in Berlin-Brandenburg %P 72 %T Biomaterialien - Einfuehrung %U %X %0 journal article %@ 1549-9634 %A Kohl, Y., Kaiser, C., Bost, W., Stracke, F., Fournelle, M., Wischke, C., Thielecke, H., Lendlein, A., Kratz, K., Lemor, R. %D 2011 %J Nanomedicine: Nanotechnology, Biology and Medicine %N 2 %P 228-237 %R doi:10.1016/j.nano.2010.07.006 %T Preparation and Biological Evaluation of Multifunctional PLGA-Nanoparticles designed for Photoacoustic Imaging %U https://doi.org/10.1016/j.nano.2010.07.006 2 %X The excellent photoacoustic properties in combination with the positive biological results qualify the dye-loaded PLGA particles as promising candidates for a resorbable photoacoustic contrast system. %0 conference lecture %@ %A Lendlein, A. %D 2011 %J 16th International Conference of the European Society for Clinical Hemorheology and Microcirculation (ESCHM) and the 30th Annual Conference of the German Society for Clinical Microcirculation and Hemorheology (DGKMH) %T Multifunctional Polymers for Cardiovascular Implants %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2011 %J Werkstoffe gestalten Zukunft, BMBF-Konferenz 2011 %T Entwicklung von multifunktionalen Biomaterialien %U %X %0 journal article %@ 0391-3988 %A Behl, M., Zotzmann, J., Lendlein, A. %D 2011 %J The International Journal of Artificial Organs %N 2 %P 231-237 %R doi:10.5301/IJAO.2011.6424 %T One-way and reversible dual-shape effect of polymer networks based on polypentadecalactone segments %U https://doi.org/10.5301/IJAO.2011.6424 2 %X of stress of 1.6 MPa, TCIE could be increased by 10 K. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2011 %J Polymers for Advanced Technologies 2011 %T Multifunctional Shape-Memory Polymers %U %X %0 conference poster %@ %A Roch, T., Pierce, B.F., Zaupa, A., Goers, J., Jung, F., Neffe, A.T., Lendlein, A. %D 2011 %J Advanced Functional Polymers for Medicine, AFPM 2011 %T Analysis of Endotoxin Content and Evaluation of Angiogenic Effects of Desaminotyrosine- and Desaminotyrosyl Tyrosine-Functionalized Gelatin %U %X %0 conference lecture %@ %A Lendlein, A. %D 2011 %J 38th Congress of the European Society for Artificial Organs, ESAO 2011 %T Smart Biomaterials %U %X %0 journal article %@ 0026-2862 %A Hiebl, B., Mrowietz, C., Lee, S., Braune, S., Knaut, M., Lendlein, A., Franke, R.P., Jung, F. %D 2011 %J Microvascular Research %N 1 %P 52-57 %R doi:10.1016/j.mvr.2011.04.001 %T Influence of polymeric microspheres on the myocardial oxygen partial pressure in the beating heart of pigs %U https://doi.org/10.1016/j.mvr.2011.04.001 1 %X pO2 decreased significantly in the myocardial area supplied by the ramus interventricularis paraconalis after injection of M15 microspheres. In contrast, the application of the M10 microspheres did not change the myocardial pO2. This finding suggests to use microspheres with diameters not exceeding 10 μm for the coronary blood flow assessment. %0 journal article %@ 1582-1838 %A Wang, W., Li, W., Ou, L., Flick, E., Mark, P., Nesselmann, C., Lux, C.A., Gatzen, H.H., Kaminski, A., Liebold, A., Luetzow, K., Lendlein, A., Li, R.-K., Steinhoff, G., Ma, N. %D 2011 %J Journal of Cellular and Molecular Medicine %N 9 %P 1989-1998 %R doi:10.1111/j.1582-4934.2010.01130.x %T Polyethylenimine-mediated gene delivery into human bone marrow mesenchymal stem cells from patients %U https://doi.org/10.1111/j.1582-4934.2010.01130.x 9 %X Transplantation of mesenchymal stem cells (MSCs) derived from adult bone marrow has been proposed as a potential therapeutic approach for postinfarction left ventricular (LV) dysfunction. However, age-related functional decline of stem cells has restricted their clinical benefits after transplantation into the infarcted myocardium. The limitations imposed on patient cells could be addressed by genetic modification of stem cells. This study was designed to improve our understanding of genetic modification of human bone marrow derived mesenchymal stem cells (hMSCs) by polyethylenimine (PEI, branched with Mw 25 kDa), one of non-viral vectors that show promise in stem cell genetic modification, in the context of cardiac regeneration for patients. We optimized the PEI-mediated reporter gene transfection into hMSCs, evaluated whether transfection efficiency is associated with gender or age of the cell donors, analyzed the influence of cell cycle on transfection, and investigated the transfer of therapeutic vascular endothelial growth factor gene (VEGF). %0 book part %@ %A Rickert, D., Hiebl, B., Fuhrmann, R., Jung, F., Lendlein, A., Franke, R.-P. %D 2011 %J Handbook of Biodegradable Polymers: Synthesis, Characterization and Applications %P 309-340 %T Regenerative Medicine: Reconstruction of Tracheal and Pharyngeal Mucosal Defects in Head and Neck Surgery %U %X %0 journal article %@ 0935-9648 %A Kumar, U.N., Kratz, K., Heuchel, M., Behl, M., Lendlein, A. %D 2011 %J Advanced Materials %N 36 %P 4157-4162 %R doi:10.1002/adma.201102251 %T Shape-Memory Nanocomposites with Magnetically Adjustable Apparent Switching Temperatures %U https://doi.org/10.1002/adma.201102251 36 %X The apparent switching temperatures (Tsw,app), which need to be exceeded by the environmental temperature (Tenv) to initialize a shape-memory effect (SME) in magnetosensitive dual- or triple-shape composites, are systematically adjusted by application of a constant weak alternating magnetic field. This adaptation of Tsw,app is fully reversible and results from the combination of environmental and inductive heating. %0 journal article %@ 0391-3988 %A Kratz, K., Habermann, R., Becker, T., Richau, K., Lendlein, A. %D 2011 %J The International Journal of Artificial Organs %N 2 %P 225-230 %R doi:10.5301/IJAO.2011.6404 %T Shape-memory properties and degradation behavior of multifunctional electro-spun scaffolds %U https://doi.org/10.5301/IJAO.2011.6404 2 %X Multifunctional polymer-based biomaterials, which combine degradability and shape-memory capability, are promising candidate materials for the realization of active self-anchoring implants. In this work we explored the shape-memory capability as well as the hydrolytic and enzymatic in vitro degradation behavior of electro-spun scaffolds prepared from a multiblock copolymer, containing hydrolytically degradable poly(p-dioxanone) (PPDO) and poly(e-caprolactone) (PCL) segments, which we have named PDC.?Electro-spun PDC scaffolds with an average deposit thickness of 80 ± 20 µm and a porosity in the range from 70% to 80% were prepared, where the single fiber diameter was around 3 µm. Excellent shape-memory properties were achieved with high recovery rate (Rr) values in the range of Rr = 92% to 98% and a recovery stress of smax = 4.6 MPa to 5.0 MPa. The switching temperature (Tsw) and the characteristic temperature obtained under constant strain recovery conditions (Ts,max) were found in the range from 32°C to 35°C, which was close to the melting temperature (Tm,PCL) associated to the poly(e-caprolactone) domains. ?A linear mass loss was observed in both hydrolytic and enzymatic degradation experiments. The mass loss was substantially accelerated, in enzymatic degradation when Pseudomonas cepacia lipase was added, which was reported to accelerate the degradation of PCL. During hydrolytic degradation a continuous decrease in elongation at break (eB) from eB = 800% to 15% was observed in a time period of 92 days, while in enzymatic degradation experiments a complete mechanical failure was obtained after 4 days. %0 journal article %@ 0935-9648 %A Kratz, K., Madbouly, S.A., Wagermeier, W., Lendlein, A. %D 2011 %J Advanced Materials %N 35 %P 4058-4062 %R doi:10.1002/adma.201102225 %T Temperature-Memory Polymer Networks with Crystallizable Controlling Units %U https://doi.org/10.1002/adma.201102225 35 %X The switching temperature,Tsw, which must be exceeded to initialize a shape-memory effect (SME), and Tσ,max, a temperature related to the recovery stress maximum under constant strain-activation conditions, are adjusted systematically over a wide temperature range for temperature-memory polymers. The polymers are based on crosslinked poly[ethylene-ran-(vinyl acetate)] with crystallizable controlling units and exhibit a broad melting temperature range. %0 conference poster %@ %A Rueder, C., Sauter, T., Becker, T., Kratz, K., Hiebl, B., Jung, F., Lendlein, A., Zohlnhoefer, D. %D 2011 %J 16th International Conference of the European Society for Clinical Hemorheology and Microcirculation (ESCHM) and the 30th Annual Conference of the German Society for Clinical Microcirculation and Hemorheology (DGKMH) %T Viability, proliferation, apoptosis and adhesion of smooth muscle cells (SMCs) and endothelial cells (HUVECs) on degradable electro-spun structures %U %X %0 book part %@ %A Sisson, A.L., Schroeter, M., Lendlein, A. %D 2011 %J Handbook of Biodegradable Polymers: Synthesis, Characterization and Applications %P 1-21 %T Polyesters %U %X Biomaterials are defined as any materials intended to interface with biological systems to analyse, treat, or replace any tissue, organ, or function of the body. The current trend in biomaterial development is shifted towards the use of biodegradable materials which have definite advantages in the fields of tissue engineering [1], and drug delivery [2]. The general principle is to use a material which achieves a specific therapeutic task and is subsequently, over time, degraded and removed harmlessly from the body. In a growing multi-billion dollar industry, biodegradable polymers are used to fabricate temporary prostheses, meshes and scaffolds for tissue regeneration, medical sutures and staples, and nano- or microscale drug delivery vehicles [3-5]. %0 book part %@ %A Lendlein, A., Wischke, C., Kratz, K., Heuchel, M., Zotzmann, J., Hiebl, B., Neffe, A., Behl, M. %D 2011 %J Comprehensive Biomaterials %P 479-496 %T Shape- Memory Polymers %U %X Medical devices such as implants, surgical instruments, extracorporal devices or wound covers, as well as controlled drug delivery systems (CDDS) require a specific combination of material properties and functions including, e.g., mechanical stability, biocompatibility, or biofunctionality. Polymeric biomaterials are of high relevance for such applications, as properties and functions can be tuned in a wide range by only small defined variations of their chemical or morphological structure. The rapid progress in surgical techniques, especially in minimally-invasive surgery, requires smart materials, which are capable of an active on-demand movement and which do not need to be removed in a second surgery. These challenges can be addressed by shape-memory polymers (SMPs) described in this chapter. SMPs are of high technological significance for biomedical applications as they enable on demand predefined changes in the shape of a device upon exposure to a suitable stimulus. Multifunctional materials are obtained when the shape-memory effect is combined with an additional function such as hydrolytic degradability, biofunctionality, and controlled drug release. Selected biomaterials with shape-memory capability are presented, including data on their biocompatibility. The potential of SMPs as a platform technology for biomedical applications is sketched by an overview on SMP-based medical devices being developed and the potential use of SMPs as matrix for CDDS. %0 conference poster %@ %A Uttamchand, N., Kratz, K., Reiche, J., Lendlein, A. %D 2011 %J Workshop an der Universitaet Potsdam %T Non-contact actuation of triple-shape effect in magnetic polymer network nanocomposites %U %X %0 conference poster %@ %A Schneider, T., Kohl, B., Sauter, T., Becker, T., Kratz, K., Schossig, M., Jung, F., Lendlein, A., Ertel, W., Schulze-Tanzil, G. %D 2011 %J 38th Congress of the European Society for Artificial Organs, ESAO 2011 %T Interaction of chondrocytes with electrospun polymer scaffolds depending on the fibre orientation %U %X %0 conference poster %@ %A Kratz, K., Reiche, J., Lendlein, A. %D 2011 %J Workshop an der Universitaet Potsdam %T Monolayer degradation experiments of polyester-based (co)polymers %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2011 %J Bayer meets Berlin Biotech, Bayer Health Care %T Polymers for Life – From biomaterial design to biomedical applications %U %X %0 journal article %@ 0391-3988 %A Reiche, J., Kratz, K., Hofmann, D., Lendlein, A. %D 2011 %J The International Journal of Artificial Organs %N 2 %P 123-128 %R doi:10.5301/IJAO.2011.6401 %T Current status of Langmuir monolayer degradation of polymeric biomaterials %U https://doi.org/10.5301/IJAO.2011.6401 2 %X Langmuir monolayer degradation (LMD) experiments with polymers possessing outstanding biomedical application potential yield information regarding the kinetics of their hydrolytic or enzymatic chain scission under well-defined and adjustable degradation conditions. A brief review is given of LMD investigations, including the author’s own work on 2-dimensional (2D) polymer systems, providing chain scission data, which are not disturbed by simultaneously occurring transport phenomena, such as water penetration into the sample or transport of scission fragments out of the sample. A knowledge-based approach for the description and simulation of polymer hydrolytic and enzymatic degradation based on a combination of fast LMD experiments and computer simulation of the water penetration is briefly introduced. Finally, the advantages and disadvantages of this approach are discussed. %0 conference lecture %@ %A Roch, T., Schroeter, M., Lendlein, A. %D 2011 %J Besuch Schueler Gruppe, 11. Klasse vom Gymnasium Teltow/Kleinmachnow %T Polymere als Biomaterialien %U %X %0 conference lecture %@ %A Mayer, A., Kratz, K., Hiebl, B., Lendlein, A., Jung, F. %D 2011 %J 16th International Conference of the European Society for Clinical Hemorheology and Microcirculation (ESCHM) and the 30th Annual Conference of the German Society for Clinical Microcirculation and Hemorheology (DGKMH) %T Interaction of primary CD14+ CD163+ VEGF-A165+ monocytes/macrophages with soft hydrophobic poly(n-butyl acrylate) networks with elastic moduli matched to human arteries %U %X %0 journal article %@ 0920-5063 %A Tzoneva, R., Weckwerth, C., Seifert, B., Behl, M., Heuchel, M., Tsoneva, I., Lendlein, A. %D 2011 %J Journal of Biomaterials Science - Polymer Edition %N 16 %P 2205-2226 %R doi:10.1163/092050610X537147 %T In Vitro Evaluation of Elastic Multiblock Co-polymers as a Scaffold Material for Reconstruction of Blood Vessels %U https://doi.org/10.1163/092050610X537147 16 %X There is a need to create cell- and histocompatible implant materials, which might temporarily replace the mechanical function of a native tissue for regenerative therapies. To match the elastic behavior of the native tissue two different multiblock co-polymers were investigated: PDC, consisting of poly(p-dioxanone) (PPDO)/poly(ɛ-caprolactone) (PCL), and PDD, based on PPDO/poly((adipinate-alt-1,4-butanediol)-co-(adipinate-alt-ethylene glycol)-co-adipinate-alt-diethylene glycol) (Diorez). PDC is capable of a shape-memory effect. Both multiblock co-polymers show an improved elasticity compared to materials applied in established vascular prosthesis. PDD is softer than PDC at 20°C, while PDC maintains its elasticity at 37°C. Thermodynamic characteristics indicate a more polar surface of PDD. Low cell adhesion was found on surfaces with low molar free energy of hysteresis (ΔG) derived from contact angle measurements in wetting and dewetting mode and high cell adhesion on high-ΔG surfaces. An increasing content of PCL in PDC improved cell adhesion and spreading of human umbilical vein endothelial cells. The prothrombotic potential of PDD is higher than PDC. Finally, it is concluded that PDC is a promising material for vascular tissue engineering because of its improved elastic properties, as well as balanced prothrombotic and anti-thrombotic properties with endothelial cells. %0 journal article %@ 1582-1838 %A Ou, L., Li, W., Zhang, Y., Wang, W., Liu, J., Sorg, H., Furlani, D., Gaebel, R., Mark, P., Klopsch, C., Wang, L., Luetzow, K., Lendlein, A., Wagner, K., Klee, D., Liebold, A., Li, R.-K., Kong, D., Steinhoff, G., Ma, N. %D 2011 %J Journal of Cellular and Molecular Medicine %N 6 %P 1310-1318 %R doi:10.1111/j.1582-4934.2010.01086.x %T Intracardiac injection of matrigel induces stem cell recruitment and improves cardiac functions in a rat myocardial infarction model %U https://doi.org/10.1111/j.1582-4934.2010.01086.x 6 %X Conclusions: Intracardiac Matrigel injection restores myocardial functions following MI, which may attribute to the improved recruitment of CD34+ and c-Kit+ stem cells. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2011 %J 24th European Conference on Biomaterials, ESB 2011 %T Designing Multifunctional Shape-Memory Polymers and Exploring their Application Potential in Implants %U %X %0 conference poster %@ %A Kobuch, K.A., Maier, M., Feucht, N., Wolfstein, A., Streufert, D., Lohmann, C.P., Kamlage, S., Neffe, A.T., Lendlein, A. %D 2011 %J Advanced Functional Polymers for Medicine, AFPM 2011 %T In vivo Evaluation of a Multifunctional Hydrogel System for Local Application on the Retina %U %X %0 journal article %@ 0391-3988 %A Kohl, Y., Kaiser, C., Bost, W., Stracke, F., Thielecke, H., Wischke, C., Lendlein, A., Kratz, K., Lemor, R. %D 2011 %J The International Journal of Artificial Organs %N 2 %P 249-252 %R doi:10.5301/IJAO.2011.6405 %T Near-infrared dye-loaded PLGA nanoparticles prepared by spray drying for photoacoustic applications %U https://doi.org/10.5301/IJAO.2011.6405 2 %X Conclusion: The high optical absorption at the relevant NIR-wavelength around 800 nm in combination with absence of cytotoxicity qualifies the ICG-loaded PLGA particles as promising candidates for degradable photoacoustic contrast agents. %0 conference lecture (invited) %@ %A Lendlein, A., Neffe, A., Wischke, C. %D 2011 %J 3rd International Conference on Smart Materials and Nanotechnology in Engineering, SMN 2011 %T Shape-memory Polymers as Platform Technology for Multifunctional Materials %U %X %0 journal article %@ 1525-7797 %A Zaupa, A., Neffe, A.T., Pierce, B.F., Noechel, U., Lendlein, A. %D 2011 %J Biomacromolecules %N 1 %P 75-81 %R doi:10.1021/bm101029k %T Influence of Tyrosine-Derived Moieties and Drying Conditions on the Formation of Helices in Gelatin %U https://doi.org/10.1021/bm101029k 1 %X The single and triple helical organization of protein chains strongly influences the mechanical properties of gelatin-based materials. A chemical method for obtaining different degrees of helical organization in gelatin is covalent functionalization, while a physical method for achieving the same goal is the variation of the drying conditions of gelatin solutions. Here we explored how the introduction of desaminotyrosine (DAT) and desaminotyrosyl tyrosine (DATT) linked to lysine residues of gelatin influenced the kinetics and thermodynamic equilibrium of the helicalization process of single and triple helices following different drying conditions. Drying at a temperature above the helix-to-coil transition temperature of gelatin (T > Tc, called vshort) generally resulted in gelatins with relatively lower triple helical content (Xc,t = 1−2%) than lower temperature drying (T < Tc, called vlong) (Xc,t = 8−10%), where the DAT(T) functional groups generally disrupted helix formation. While different helical contents affected the thermal transition temperatures only slightly, the mechanical properties were strongly affected for swollen hydrogels (E = 4−13 kPa for samples treated by vlong and E = 120−700 kPa for samples treated by vshort). This study shows that side group functionalization and different drying conditions are viable options to control the helicalization and macroscopic properties of gelatin-based materials. %0 journal article %@ 1042-7147 %A Cui, J., Kratz, K., Heuchel, M., Hiebl, B., Lendlein, A. %D 2011 %J Polymers for Advanced Technologies %N 1 %P 180-189 %R doi:10.1002/pat.1733 %T Mechanically active scaffolds from radio-opaque shape-memory polymer-based composites %U https://doi.org/10.1002/pat.1733 1 %X composites, while Tsw was found to be close to the applied Tprog. The feasibility of actively moving scaffolds was demonstrated using model scaffolds, where originally square-shaped pores were temporarily fixed in an expanded circular shape at different Tprog. We found that the kinetics of the shape change obtained under physiological conditions could be adjusted by variation of Tprog between 1 and 6 hr. Such radio-opaque scaffolds could serve as model scaffolds for investigating the active mechanical stimulation of cells in vitro or in vivo. %0 journal article %@ 0391-3988 %A Zaupa, A., Neffe, A.T., Pierce, B.F., Lendlein, A., Hofmann, D. %D 2011 %J The International Journal of Artificial Organs %N 2 %P 139-151 %R doi:10.5301/IJAO.2010.6083 %T A molecular dynamic analysis of gelatin as an amorphous material: Prediction of mechanical properties of gelatin systems %U https://doi.org/10.5301/IJAO.2010.6083 2 %X Biomaterials are used in regenerative medicine for induced autoregeneration and tissue engineering. This is often challenging, however, due to difficulties in tailoring and controlling the respective material properties. Since functionalization is expected to offer better control, in this study gelatin chains were modified with physically interacting groups based on tyrosine with the aim of causing the formation of physical crosslinks. This method permits application-specific properties like swelling and better tailoring of mechanical properties. The design of the crosslink strategy was supported by molecular dynamic (MD) simulations of amorphous bulk models for gelatin and functionalized gelatins at different water contents (0.8 and 25 wt.-%). The results permitted predictions to be formulated about the expected crosslink density and its influence on equilibrium swelling behavior and on elastic material properties. The models of pure gelatin were used to validate the strategy by comparison between simulated and experimental data such as density, backbone conformation angle distribution, and X-ray scattering spectra. A key result of the simulations was the prediction that increasing the number of aromatic functions attached to the gelatin chain leads to an increase in the number of physical netpoints observed in the simulated bulk packing models. By comparison with the Flory-Rehner model, this suggested reduced equilibrium swelling of the functionalized materials in water, a prediction that was subsequently confirmed by our experimental work. The reduction and control of the equilibrium degree of swelling in water is a key criterion for the applicability of functionalized gelatins when used, for example, as matrices for induced autoregeneration of tissues. %0 journal article %@ 1742-7061 %A Neffe, A.T., Loebus, A., Zaupa, A., Stoetzel, C., Mueller, F.A., Lendlein, A. %D 2011 %J Acta Biomaterialia %N 4 %P 1693-1701 %R doi:10.1016/j.actbio.2010.11.025 %T Gelatin Functionalization with Tyrosine Derived Moieties for Increasing the Interaction with Hydroxyapatite Fillers %U https://doi.org/10.1016/j.actbio.2010.11.025 4 %X Combining gelatins functionalized with the tyrosine-derived groups desaminotyrosine or desaminotyrosyl tyrosine with hydroxyapatite (HAp) led to the formation of composite materials with much lower swelling ratio than of the pure matrices. Shifts of IR bands related to the free carboxyl groups could be observed in the presence of HAp, which suggested a direct interaction of matrix and filler that formed additional physical crosslinks in the material. In tensile tests and rheological measurements, the composites equilibrated in water had increased Young’s moduli (from 200 kPa up to 2 MPa) and tensile strength (from 57 kPa up to 1.1 MPa) compared to the matrix polymers without affecting the elongation at break. Furthermore, an increased thermal stability from 40 °C to 85 °C of the networks could be demonstrated. The differences of the behaviour of the functionalized gelatins to pure gelatin as matrix suggested an additional stabilizing bond between the incorporated aromatic groups to the hydroxyapatite as supported by the IR results. The composites can potentially be applied as bone fillers. %0 conference lecture %@ %A Lendlein, A. %D 2011 %J 3rd China-Europe Conference on Biomaterials in Regenerative Medicine, CESB 2011 %T Shape-Memory Polymers and their Application Potential as Biomaterials %U %X %0 conference lecture %@ %A Behl, M., Zotzmann, J., Feng, Y., Lendlein, A. %D 2011 %J 3rd International Conference on Smart Materials and Nanotechnology in Engineering, SMN 2011 %T Triple-shape effect of copolymer networks based on polypentadecalactone- and poly(Epsilon-caprolactone)-segments %U %X %0 journal article %@ 1310-1331 %A Krasteva, V., Pehlivanova, V., seifert, B., Luetzow, K., Tsoneva, I., Richau, K., Lendlein, A., Tzoneva, R. %D 2011 %J Dokladi na Balgarskata Akademija na Naukite / Comptes rendus de l'Academie Bulgare des Sciences %N 4 %P 535-544 %T Influence of AC electric fields on the adsorption of plasma proteins onto nanofiber biomaterials %U 4 %X of plasma proteins. Frequencies above 10 Hz lead to diminished protein adsorption. %0 conference poster %@ %A Sauter, T., Kratz, K., Lendlein, A. %D 2011 %J ESAO Winter School 2011 %T Hydrolytic and Enzymatic Degradation Behaviour of Multiblock Copolymers with Different Fiber Dimension %U %X %0 conference lecture %@ %A Mrowietz, C., Peuker, A., Schunk, W.-H., Blaschke, F., Mueller, D., Lendlein, A., Jung, F. %D 2011 %J 16th International Conference of the European Society for Clinical Hemorheology and Microcirculation (ESCHM) and the 30th Annual Conference of the German Society for Clinical Microcirculation and Hemorheology (DGKMH) %T Influence of different Cytochrom-P450 Eicosanoids on the Ristocetin-induced platelet aggregation %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2011 %J Institutskolloquium am Leibniz-Institut fuer Neue Materialien %T Shape Memory Polymers %U %X %0 conference lecture %@ %A Lendlein, A. %D 2011 %J World Conference on Regenerative Medicine %T Multifunctional Biomaterials %U %X %0 journal article %@ 1386-0291 %A Mayer, A., Lee, S., Lendlein, A., Jung, F., Hiebl, B. %D 2011 %J Clinical Hemorheology and Microcirculation %N 1-3 %P 57-63 %R doi:10.3233/CH-2011-1395 %T Efficacy of CD14+ blood monocytes/macrophages isolation: Positive versus negative MACS™ protocol %U https://doi.org/10.3233/CH-2011-1395 1-3 %X Cardiovascular implants such as stents or artificial vascular grafts established in clinical application to date are generally designed as long-term implants. An important requirement for the successful application of these devices is the haemocompatibility of their interface to the blood stream, which often is approached by polymeric coatings. Modern therapies are aiming at curative treatments (Regenerative Medicine) by inducing the in vivo formation of a new endothelial layer on the implant surface ensuring an optimal haemocompatibility based on the generated glycocalyx. A promising approach for providing the required biological stimulus is the secretion of pro-angiogenic factors (such as VEGF-A) by autologous CD14+ monocytes/macrophages (mo/mΦ), which can be induced by previous angiogenic stimulation. While protocols for negative and positive immune-isolation are already established, this study was aimed to evaluate the efficacy of a positive and a negative MACS™ based immune-isolation protocol by analysing the yield, the purity and the activation status of the isolated CD14+ mo/mΦ. Both protocols enabled the isolation of more than 80% (positive isolation) and 86% (negative isolation) CD14+ mo/mΦ representing approximately 1.3 × 107 CD14+ mo/mΦ from 1 ml buffy coat. Less than 10% of these cells were also positive for CD69. Latter is an important selection criterion as CD69 is a marker characteristic for classically activated and catabolic active mo/mΦ which can negatively affect the endothelialisation process. As the negative immune-isolation protocol resulted in a cell fraction meeting the requirements on a pure cell fraction (percentage of contaminating cells < 15%) this isolation method is advantageous although it was more time consuming than the positive isolation protocol. %0 conference poster %@ %A Roch, T., Mayer, A., Kratz, K., Cui, J., Lendlein, A., Jung, F. %D 2011 %J 16th International Conference of the European Society for Clinical Hemorheology and Microcirculation (ESCHM) and the 30th Annual Conference of the German Society for Clinical Microcirculation and Hemorheology (DGKMH) %T Immuno-compatibility of soft hydrophobic poly(n-butyl acrylate) networks with elastic moduli for regeneration of functional tissues %U %X %0 report part %@ %A Hiebl, B., Lendlein, A. %D 2011 %J Technologiereport - Regenerative Medizin in Berlin-Brandenburg %P 75-78 %T Physiologie der Biomaterial-Zell-Grenzflaeche %U %X %0 report part %@ %A Jung, F., Lendlein, A. %D 2011 %J Technologiereport - Regenerative Medizin in Berlin-Brandenburg %P 78-80 %T Biofunktionale Implantate %U %X %0 report part %@ %A Neffe, A.T., Behl, M., Lendlein, A. %D 2011 %J Technologiereport - Regenerative Medizin in Berlin-Brandenburg %P 73-75 %T Polymere %U %X %0 conference poster %@ %A Sauter, T., Kratz, K., Lendlein, A. %D 2011 %J MRS Fall 2011 Meeting, Symposium V %T Impact of Different Single Fiber Diameter and Variation of the Programming Temperature on the Shape-Memory Properties of Electro-spun Scaffolds Prepared from Amorphous Polyetherurethanes %U %X %0 journal article %@ 0391-3988 %A Lendlein, A., Neffe, A.T., Pierce, B., Vienken, J. %D 2011 %J The International Journal of Artificial Organs %N 2 %P 71-75 %R doi:10.5301/IJAO.2011.6422 %T Why are so few degradable polymeric biomaterials currently established in clinical applications? %U https://doi.org/10.5301/IJAO.2011.6422 2 %X No abstract %0 conference lecture %@ %A Lendlein, A. %D 2011 %J GDCh-Kolloquium %T Multifunktionale Polymernetzwerke und deren Anwendungspotenzial in der Medizin %U %X %0 conference poster %@ %A Neffe, A.T., Kobuch, K.A., Maier, M., Feucht, N., Lohmann, C.P., Wolfstein, A., Streufert, D., Kamlage, S., Lendlein, A. %D 2011 %J Advanced Functional Polymers for Medicine, AFPM 2011 %T In vitro and in vivo Evaluation of a Multifunctional Hyaluronic acid based Hydrogel System for Local Application on the Retina %U %X %0 journal article %@ 2095-0179 %A Wang, H., Feng, Y., Behl, M., Lendlein, A., Zhao, H., Xiao, R., Lu, J., Zhang, L., Guo, J. %D 2011 %J Frontiers of Chemical Science and Engineering %N 3 %P 392-400 %R doi:10.1007/s11705-011-1202-0 %T Hemocompatible polyurethane/gelatin-heparin nanofibrous scaffolds formed by a bi-layer electrospinning technique as potential artificial blood vessels %U https://doi.org/10.1007/s11705-011-1202-0 3 %X In this paper, a scaffold, which mimics the morphology and mechanical properties of a native blood vessel is reported. The scaffold was prepared by sequential bi-layer electrospinning on a rotating mandrel-type collector. The tubular scaffolds (inner diameter 4 mm, length 3 cm) are composed of a polyurethane (PU) fibrous outer-layer and a gelatin-heparin fibrous inner-layer. They were fabricated by electrospinning technology, which enables control of the composition, structure, and mechanical properties of the scaffolds. The microstructure, fiber morphology and mechanical properties of the scaffolds were examined by means of scanning electron microscopy (SEM) and tensile tests. The PU/gelatinheparin tubular scaffolds have a porous structure. The scaffolds achieved a breaking strength (3.7±0.13 MPa) and an elongation at break (110±8%) that are appropriate for artificial blood vessels. When the scaffolds were immersed in water for 1 h, the breaking strength decreased slightly to 2.2±0.3 MPa, but the elongation at break increased to 145±21%. In platelet adhesion tests the gelatin-heparin fibrous scaffolds showed a significant suppression of platelet adhesion. Heparin was released from the scaffolds at a fairly uniform rate during the period of 2nd day to 9th day. The scaffolds are expected to mimic the complex matrix structure of native arteries, and to have good biocompatibility as an artificial blood vessel owing to the heparin release. %0 conference lecture %@ %A Mrowietz, C., Hiebl, B., Schunk, W.-H., Mueller, D., Blaschke, F., Franke, R.-P., Lendlein, A., Jung, F. %D 2011 %J 16th International Conference of the European Society for Clinical Hemorheology and Microcirculation (ESCHM) and the 30th Annual Conference of the German Society for Clinical Microcirculation and Hemorheology (DGKMH) %T Effects of Tacrolimus or Sirolimus on the adhesion of vascular wall cells: controlled in-vitro comparison study %U %X %0 journal article %@ 0391-3988 %A Feng, Y., Lu, J., Behl, M., Lendlein, A. %D 2011 %J The International Journal of Artificial Organs %N 2 %P 103-109 %R doi:10.5301/IJAO.2011.6402 %T Degradable depsipeptide-based multiblock copolymers with polyester or polyetherester segments %U https://doi.org/10.5301/IJAO.2011.6402 2 %X Polydepsipeptides, alternating copolymers of an a-amino acid and a a-hydroxy acid, are an interesting group of degradable polymers. They have gained attention as potential degradable implant materials. Polydepsipeptides are expected to have better biocompatibility in vivo during the degradation process than aliphatic polyesters. Various depsipeptide-based polymers with or without pendant functional groups have been synthesized via ring-opening polymerization of corresponding morpholine-2,5-dione derivatives. The different polymer architectures of the polymers, for example, providing an alternating, random, diblock, triblock, or multiblock structure, can be obtained by appropriate selection of the polymerization reaction, which may be ring-opening or polyaddition. Recently, we synthesized thermoplastic phase-segregated copolymers with a multiblock structure containing polydepsipeptides and poly(e-caprolactone) or poly(p-dioxanone) segments via coupling of the respective diols using an aliphatic diisocyanate. The obtained multiblock copolymers showed good elastic properties at 25°C and 75°C. Furthermore, they exhibited a shape-memory capability. Here, we summarize the synthesis, biodegradation behavior and shape-memory properties of the multiblock copolymers. In addition, we introduce new combinations of depsipeptide/poly(ether)ester segments in multiblock copolymers. The depsipeptide-based multiblock copolymers have potential applications as biomaterials for controlled drug release, tissue engineering scaffolds, or base materials for biofunctional implants. %0 journal article %@ 0391-3988 %A Yoba N’Goma, P., Radke, W., Malz, F., Ziegler, H.J., Zierke, M., Behl, M., Lendlein, A. %D 2011 %J The International Journal of Artificial Organs %N 2 %P 110-119 %R doi:10.5301/IJAO.2011.6409 %T Characterization of multiblock copolymers by chromatographic techniques %U https://doi.org/10.5301/IJAO.2011.6409 2 %X Multiblock copolymers (MBC) composed of blocks of poly(1,4-dioxanone) (PPDO) and poly(e-caprolactone) (PCL) were investigated in order to gain information on the extend of chemical heterogeneity of the samples. A gradient chromatographic method was established allowing separation of purely PPDO- from purely PCL-containing chains. Application of the gradient to MBC made of PPDO- and PCL-diols connected by trimethylhexamethylene diisocyanate (TMDI) resulted in two well separated peaks which were analyzed by means of FTIR, 1H-NMR and pyrolysis GC-MS. It was shown that the first peak was composed to a large extent of PPDO and only lower amounts of PCL were incorporated. Conversely, the second peak consisted predominantly of PCL with only a minor fraction of PPDO. Thus, the MBCs having PPDO and PCL segments show an unexpected broad chemical heterogeneity. %0 journal article %@ 1386-0291 %A Battig, A., Hiebl, B., Feng, Y., Lendlein, A., Behl, M. %D 2011 %J Clinical Hemorheology and Microcirculation %N 1-3 %P 161-172 %R doi:10.3233/CH-2011-1391 %T Biological evaluation of degradable, stimuli-sensitive multiblock copolymers having polydepsipeptide- and poly(Epsilon-caprolactone) segments in vitro %U https://doi.org/10.3233/CH-2011-1391 1-3 %X Polydepsipeptides, alternating copolymers consisting of α-amino acids and α-hydroxy acids, are degradable polymers. Depsipeptide-based polymers of varied architectures can be synthesized via ring-opening polymerization of various morpholine-2,5-dione derivatives. Thermoplastic phase-segregated multiblock copolymers with poly(ε-caprolactone) (PCL) and poly(iso-butyl-morpholinedione) segments have been synthesized from the macrodiols and an aliphatic diisocyanate as a coupling agent. The respective multiblock copolymers showed shape-memory capabilities and good elastic properties, making them attractive candidates for potential application as biomaterials for controlled drug release systems, scaffolds to be applied in tissue engineering or biofunctional implants. Thus, these abilities cumulate to form multifunctional materials, combining degradability with shape-memory capability. The advantages of depsipeptide-based multiblock copolymers compared to previously reported poly(ether)ester-derived biomaterials having shape-memory property may result from their different degradation products, as the resulting α-amino acids may act as a buffer for the hydroxy acids, thereby stabilizing pH values. In this context, we report on the biological evaluation of material samples in accordance with international standards (EN DIN ISO 10993-5 and 10993-12). Here, extracts of the substrates were exposed to a continuous fibroblast like cell line (L929) to study cytocompatibility of extractable substrates. Cell viability, morphology, LDH-release (as a parameter for the functional integrity of the cell membrane), activity of the mitochondrial dehydrogenases (as a parameter of the cell activity) and assembly of the actin- and vinculin cytoskeleton indicated no incompatibilities between the extracts and L929 cells. These results suggest that depsipeptide-based multiblock copolymers are promising candidates for soft, multifunctional implant materials. %0 conference lecture %@ %A Lendlein, A. %D 2011 %J Brandenburg im internationalen Jahr der Chemie der Vereinten Nationen %T Kunststoffe mit Formgedaechtnis %U %X %0 conference lecture %@ %A Lendlein, A. %D 2011 %J Life Science and Health Innovation %T Multifunctional Biomaterials %U %X %0 conference poster %@ %A Schneider, T., Kohl, B., Sauter, T., Becker, T., Kratz, K., Schossig, M., Hiebl, B., Jung, F., Lendlein, A., Ertel, W., Schulze-Tanzil, G. %D 2011 %J Advanced Functional Polymers for Medicine, AFPM 2011 %T Viability, adhesion and differentiated phenotype of articular chondrocytes on degradable polymers and electro-spun structures thereof %U %X %0 conference lecture %@ %A Mayer, A., Kratz, K., Hiebl, B., Lendlein, A., Jung, F. %D 2011 %J 16th International Conference of the European Society for Clinical Hemorheology and Microcirculation (ESCHM) and the 30th Annual Conference of the German Society for Clinical Microcirculation and Hemorheology (DGKMH) %T Support of HUVEC proliferation by pro-angiogenic intermediate CD163+ monocytes/macrophages: A co-culture experiment %U %X %0 journal article %@ 0391-3988 %A Pierce, B.F., Bellin.K., Behl, M., Lendlein, A. %D 2011 %J The International Journal of Artificial Organs %N 2 %P 172-179 %R doi:10.5301/IJAO.2011.6413 %T Demonstrating the influence of water on shape-memory polymer networks based on poly[(rac-lactide)-co-glycolide] segments in vitro %U https://doi.org/10.5301/IJAO.2011.6413 2 %X Thermally-responsive shape-memory polymers (SMP) are highly promising implant materials for applications in minimally-invasive surgery since the shape-memory effect (SME) enables the implantation of a bulky device in a compressed temporary state through a small incision. When heated to a temperature exceeding the material switching temperature (Tsw), the device recovers its original bulky shape. Therefore, SMP implants with Tsw ~ 37°C are required for such applications because the body cannot withstand excessive applications of heat. Here, Tsw of networks based on poly[(rac-lactide)-co-glycolide] star-shaped macrotriol or macrotetrols with 19-22 wt% glycolide content, varying oligomer molecular weight (Mn=3000-10000 g·mol-1), and netpoint functionality (f=3 or 4) were lowered from 55-66°C to below body temperature via the uptake of water, which also induced SME at body temperature. Programmed samples kept their temporary shape at room temperature in water as well as at 37°C under dry conditions but recovered in 37°C water. Water uptake/swelling studies and FTIR analysis indicated that the mechanism of solvent-induced SME involved the plasticization of water in switching domains as opposed to changes in swelling or hydrogen bonding. This indirect actuation of SME by using a combination of solvent and heat could be exploited in easy-to-handle shape-memory implant with slower degradation kinetics. %0 journal article %@ 1552-4973 %A Loebler, M., Sternberg, K., Stachs, O., Allemann, R., Grabow, N., Roock, A., Kreiner, C.F., Streufert, D., Neffe, A.T., Hanh, B.D., Lendlein, A., Schmitz, K.-P., Guthoff, R. %D 2011 %J Journal of Biomedical Materials Research B %N 2 %P 388-395 %R doi:10.1002/jbm.b.31826 %T Polymers and drugs suitable for the development of a drug delivery drainage system in glaucoma surgery %U https://doi.org/10.1002/jbm.b.31826 2 %X Implantation of a glaucoma drainage system is an appropriate therapeutic intervention in some glaucoma patients. However, one drawback with this approach is the fibrotic tissue response to the implant material, leading to reduced flow of aqueous liquid or complete blockage of the drainage system. As a basis for developing an aqueous shunt we report here investigations with poly(3-hydroxybutyrate) (P(3HB)) and poly(4-hydroxybutyrate) (P(4HB)) as polymer matrices and with paclitaxel (PTX) and triamcinolone acetonide (TA) as drugs that might, in combination, delay or prevent the process of fibrosis by reducing fibroblast activity. P(3HB) and P(4HB) were fabricated into test prototypes with 500 μm outer and 200 μm inner diameter and ∼1 cm length. The antiproliferative agent PTX and the anti-inflammatory agent TA were incorporated into the polymer matrices and were released by diffusion. In vitro cell assays demonstrated that the polymers have the potential to reduce fibroblast viability, while TA showed differential inhibition of Tenon fibroblasts, but not cornea keratocytes. Implantation of polymer disks and prototype devices into rabbit eyes confirmed the good biocompatibility of the materials. The combined use of a poly(hydroxybutyrate) polymer with PTX or TA has the potential to reduce the fibrosis associated with conventional glaucoma drainage systems. %0 journal article %@ 1439-9598 %A Lendlein, A., Philipp, B. %D 2011 %J Nachrichten aus der Chemie %N 6 %P 624-628 %T Ein guter Ort fuer Polymere %U 6 %X Geschichte zurückblicken. %0 journal article %@ 1022-1352 %A Lendlein, A., Philipp, B. %D 2011 %J Macromolecular Chemistry and Physics %N 7 %P 753-757 %R doi:10.1002/macp.201000762 %T Polymers in the Berlin–Brandenburg Region: A Brief Review on the History on the Occasion of the 20th Anniversary of the German Reunification %U https://doi.org/10.1002/macp.201000762 7 %X No abstract %0 conference object %@ 1076-3279 %A Lendlein, A. %D 2011 %J Tissue Engineering A %P 537 %R doi:10.1089/ten.tea.2010.1502 %T Biomaterials for Regenerative Medicine %U https://doi.org/10.1089/ten.tea.2010.1502 %X No abstract %0 journal article %@ 1439-9598 %A Lendlein, A., Hofmann, D., Scharnagl, N. %D 2011 %J Nachrichten aus der Chemie %N 2 %P 117-120 %R doi:10.1002/nadc.201178450 %T Abbaubare Polymere in der Medizin %U https://doi.org/10.1002/nadc.201178450 2 %X Polymerbasierte, abbaubare Biomaterialien sind eine Schlüsseltechnik für die moderne Medizin. Sie kommen in verschiedenen Medizinprodukten und Wirkstofffreisetzungssystemen zum Einsatz. Es ist zu erwarten, dass multifunktionale Polymere wesentliche Beiträge zu kausalen (regenerative Medizin), schonenden (minimalinvasive Medizin) und gezielten (Nanomedizin) Therapien leisten werden. %0 book part %@ %A Schroeter, M., Wildemann, B., Lendlein, A. %D 2011 %J Regenerative Medicine - From Protocol to Patient %P 469-492 %R doi:10.1007/978-90-481-9075-1_20 %T Biodegradable Materials %U https://doi.org/10.1007/978-90-481-9075-1_20 %X This chapter gives an overview about polymeric materials established in clinical use such as polyesters, polyurethanes, polyanhydrides, or carbohydrates. It describes further their synthesis and exemplary applications such as surgical sutures. Finally the importance of a continuing development of novel materials for future applications is pointed out, since the number of potential applications in the medical field is expanding rapidly. %0 conference lecture %@ %A Lendlein, A. %D 2011 %J Nachwuchsakademie Medizintechnik, NAMT 2011 %T Multifunctional Materials %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2011 %J Multifunctional Biomaterials and Polymer-based Controlled Drug Release Systems, 2nd Sino-German Symposium %T Key Issues in the Development of Multifunctional Biomaterials %U %X %0 conference poster %@ %A Wischke, C., Loebler, M., Neffe, A.T., Hanh, B.D., Zierke, M., Sternberg, K., Schmitz, K.-P., Guthoff, R., Lendlein, A. %D 2011 %J Advanced Functional Polymers for Medicine, AFPM 2011 %T A Blend of Poly(Epsilon-caprolactone) and Poly[(Epsilon-caprolactone)-co-glycolide] with Remarkable Mechanical Features and Wide Applicability as Biomaterial %U %X %0 conference poster %@ %A Lange, M., Luetzow, K., Neffe, A.T., Lendlein, A. %D 2011 %J Young European Biomaterial Scientists Designing a View for the Future, BioFuture 2011 %T Polyetherimides with 3-methoxy-1,2-propanediol moieties %U %X %0 conference poster %@ %A Wischke, C., Tripodo, G., Choi, N.-Y., Lendlein, A. %D 2011 %J Advanced Functional Polymers for Medicine, AFPM 2011 %T Design of poly(rac-lactide)-b-poly(propylene glycole)-b-poly(rac-lactide) dimethacrylate derived networks as degradable materials for biomedical application %U %X %0 journal article %@ 1022-1360 %A Lange, M., Luetzow, K., Neffe, A.T., Lendlein, A. %D 2011 %J Macromolecular Symposia %N 1 %P 40-48 %R doi:10.1002/masy.201100052 %T Synthesis and Characterization of Polyetherimides with 3-Methoxy-1,2-propanediol Moieties %U https://doi.org/10.1002/masy.201100052 1 %X Polyetherimides have been evaluated as non-toxic and steam-sterilizable and are therefore potentially suited for biomedical applications. To enable a broader range of potential applications, polyetherimides with lower Tg, higher elasticity at room temperature and better processability are required. Our concept was to explore, whether the incorporation of 3-methoxy-1,2-propanediol moieties in the main chain lead to a reduction of Tg and increase the elastic properties of the polymer compared to commercially available polyetherimides from 4,4′-(4,4′-isopropylidenediphenoxy)bis(phthalic anhydride) and 1,3-diaminobenzene. Two different monomers were synthesized and co-condensated with each other or using 4,4,4′-(4,4′-isopropylidenediphenoxy)bis(phthalic anhydride), respectively. The results proofed the successful synthesis and polymerization leading to polymers with molecular weights up to Mn = 6,400 g/mol. The polymers showed lowered Tg, resistance to heat up to 400 °C, tendencies to reduced contact angles and partially reduced E-moduli in comparison to the commercial polyetherimide ULTEM 1000. %0 conference poster %@ %A Lange, M., Luetzow, K., Neffe, A.T., Lendlein, A. %D 2011 %J Advanced Functional Polymers for Medicine, AFPM 2011 %T Synthesis and Characterization of a new Poly(ether imide) Based on 3-Methoxy-1,2-propandiol %U %X %0 journal article %@ 1743-4440 %A Lendlein, A., Wischke, C. %D 2011 %J Expert Review of Medical Devices %N 5 %P 533-537 %R doi:10.1586/erd.11.39 %T How to accelerate biomaterial development? Strategies to support the application of novel polymer-based biomaterials in implantable devices %U https://doi.org/10.1586/erd.11.39 5 %X No abstract %0 journal article %@ 1386-0291 %A Wischke, C., Lendlein, A. %D 2011 %J Clinical Hemorheology and Microcirculation %N 1-4 %P 347-355 %R doi:10.3233/CH-2011-1485 %T Designing multifunctional polymers for cardiovascular implants %U https://doi.org/10.3233/CH-2011-1485 1-4 %X Polymer-based biomaterials are extensively used in all disciplines of clinical medicine and innovations in biomaterial science are building a product pipeline, e.g., of future cardiovascular implants. Still, cardiovascular applications demand a number of extensive requirements of properties and functions to be fulfilled by the polymer matrix. This report provides an overview on some of these issues and how they can be addressed by a tailored design of novel polymer-based biomaterials. Multifunctional shape-memory polymers are highlighted as a class of materials that combine biocompatibility and the capability for stimuli-induced active movements for anchoring of implants with a controlled degradation and drug release profile to enable a functional regeneration of the tissue at the application site. %0 journal article %@ 1022-1360 %A Tripodo, G., Wischke, C., Lendlein, A. %D 2011 %J Macromolecular Symposia %N 1 %P 49-58 %R doi:10.1002/masy.201100058 %T Highly Flexible Poly(ethyl-2-cyanoacrylate) Based Materials Obtained by Incorporation of Oligo(ethylene glycol)diglycidylether %U https://doi.org/10.1002/masy.201100058 1 %X Poly(ethyl-2-cyanoacrylate) (PECA) is a polymer with potential medical or technical applications, which are limited due to its high brittleness. In this work, the capability of different ethylene or propylene glycol-based oligomers to provide flexible poly(ethyl-2-cyanoacrylate) films upon blending is analyzed. The used oligoethers have been chosen with different end groups or lateral substituents and their effects the on macroscopic behavior of the obtained materials have been characterized. During its synthesis, in situ blending of PECA was performed with increasing quantities of oligo(ethylene glycol) diglycidyl ether providing homogeneously miscible materials with single Tg's. The Tg's decreased in a concentration dependent manner and showed negative deviation from predictions by the Fox equation, possibly due to specific intermolecular interactions. Remarkably, the mechanical properties could be tailored over a wide range with Young's moduli of 0.2 to 900 MPa, which so far has not been reported for cyanoacrylate-based materials. Therefore, the concept of compatible blends should be further explored to establish flexible cyanoacrylate-based materials for various technical or biomedical applications. %0 journal article %@ 1022-1360 %A Wischke, C., Loebler, M., Neffe, A.T., Hanh, B.D., Zierke, M., Sternberg, K., Schmitz, K.-P., Guthoff, R., Lendlein, A. %D 2011 %J Macromolecular Symposia %N 1 %P 59-67 %R doi:10.1002/masy.201100050 %T A Blend of Poly(Epsilon-caprolactone) and Poly[(Epsilon-caprolactone)-co-glycolide] with Remarkable Mechanical Features and Wide Applicability as Biomaterial %U https://doi.org/10.1002/masy.201100050 1 %X Hydrolytic degradation of poly(ε-caprolactone) [PCL] can be enhanced by introduction of 8 wt.% glycolide leading to poly[(ε-caprolactone)-co-glycolide] (PCG), which has a low elongation at break εB of 4%. PCG/PCL blends (50/50 w/w) combined the advantageous features of its individual components such as mechanical properties similar to pure PCL (εB, Blend: 900 ± 230%; εB, PCL: 730 ± 50 at 20 °C), water uptake rates during degradation similar to pure PCG, and linear mass loss during bulk degradation independent from sample dimensions. The outcome of cytotoxicity studies was depending on the cell type with promising results, e.g., for Tenon fibroblasts. Easy processing of the blend was demonstrated by melt compression, foaming with CO2, and hot melt extrusion, suggesting a wide applicability as biomaterial, e.g., as drug carrier. %0 conference poster %@ %A Tripodo, G., Wischke, C., Lendlein, A. %D 2011 %J Advanced Functional Polymers for Medicine, AFPM 2011 %T Highly Flexible Poly(ethyl-2-cyanoacrylate) Based Materials Obtained by Incorporation of Oligo(ethylene glycol)diglycidylether %U %X %0 conference poster %@ %A Piluso, S., Lendlein, A., Neffe, A.T. %D 2011 %J Young European Biomaterial Scientists Designing a View for the Future, BioFuture 2011 %T Synthesis and Characterization of Gelatin Fragments Obtained by Controlled Degradation %U %X %0 journal article %@ 1022-1360 %A Piluso, S., Weigel, T., Lendlein, A., Neffe, A.T. %D 2011 %J Macromolecular Symposia %N 1 %P 199-204 %R doi:10.1002/masy.201100054 %T Synthesis and Characterization of Gelatin Fragments Obtained by Controlled Degradation %U https://doi.org/10.1002/masy.201100054 1 %X Telechelic oligomers are attractive starting materials for the preparation of materials with tailorable properties. Here, peptide chains with defined molecular weight were obtained by controlled degradation of gelatin with hydroxylamine, which resulted in the cleavage of asparaginyl-glycine bonds and formation of new aspartyl hydroxamates and amino endgroups. The reaction of gelatin with hydroxylamine resulted in fragments with molecular weights of 15, 25, 37, and 50 kDa (determined by SDS-PAGE) independently of the reaction time and conditions. The fragment mixture showed typical single and triple helical organization in WAXS spectra, but rheological studies showed lower G′ and G″ values for gels from the fragment mixture than from gelatin, and lower gel-sol transitions temperatures. A more narrow distribution was found for the fragment mixture (Mn=25 kDa, PDI=1.4) than for commercial gelatin. %0 conference poster %@ %A Piluso, S., Lendlein, A., Neffe, A.T. %D 2011 %J Advanced Functional Polymers for Medicine, AFPM 2011 %T Synthesis and Characterization of Gelatin Fragments Obtained by Controlled Degradation %U %X %0 conference poster %@ %A Behl, M., Zotzmann, J., Lendlein, A. %D 2011 %J Advanced Functional Polymers for Medicine, AFPM 2011 %T The Influence of Programming Conditions on Triple-Shape Materials Based on Copolymer Networks With Two Crystallizable Switching Segments of Poly(w-pentadecalactone) and Poly(ε-caprolactone) %U %X %0 journal article %@ 1022-1360 %A Federico, S., Lendlein, A., Neffe, A.T. %D 2011 %J Macromolecular Symposia %N 1 %P 205-212 %R doi:10.1002/masy.201100055 %T Synthesis and Characterization of a Telechelic Peptide as a Precursor for Supramolecular Networks %U https://doi.org/10.1002/masy.201100055 1 %X A peptide showing propensity for the adoption of β-sheet conformation was synthesized in order to develop a defined molecular building block as part of a toolbox for the development of polymer networks based on supramolecular interactions. The peptide was synthesized by microwave-assisted solid phase peptide synthesis and the purification was performed by Reversed Phase-High Performance Liquid Chromatography (RP-HPLC), from which a purity higher than 95 mol-% was obtained. The calculated mass was confirmed by Matrix Assisted Laser Desorption Ionization-Time of Flight-Mass Spectrometry (MALDI-ToF-MS). Further characterization of the peptide was performed by IR and 2D TOCSY, NOESY, and HSQC NMR spectroscopy, which confirmed the identity and the sequence of the peptide. %0 journal article %@ 0957-4530 %A Zotzmann, J., Ziegler, H.-J., Behl, M., Zierke, M., Radke, W., Lendlein, A. %D 2011 %J Journal of Materials Science: Materials in Medicine %N 10 %P 2147-2154 %R doi:10.1007/s10856-011-4404-6 %T Upscaling the synthesis of biodegradable multiblock copolymers capable of a shape-memory effect %U https://doi.org/10.1007/s10856-011-4404-6 10 %X Thermoplastic, phase-segregated multiblock copolymers (MBC) with shape–memory capability consisting of poly(ε-caprolactone) (PCL) switching segments and poly(p-dioxanone) (PDO) or poly(ω-pentadecalactone) (PPD) hard segments were prepared on a scale of several kilograms following a newly developed upscaling procedure. Dihydroxytelechelic poly(ether)esters were coupled by an aliphatic diisocyanate gaining products of sufficiently high molecular weights. The obtained biodegradable MBC exhibited good elastic properties and a shape–memory effect (SME) with a switching temperature (Tsw) around body temperature. The yield of the synthesis could be improved and reaction time reduced, while mechanical and shape–memory properties were not affected. These multifunctional materials, which are now available in a larger scale have a high application potential as smart implant materials especially for minimally invasive surgery. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2011 %J Innovationsforum fuer Medizintechnik 2011 %T Polymers for Biomedicine – The Interrelation between Fundamental Research and Product Development %U %X %0 journal article %@ 0391-3988 %A Piluso, S., Hiebl, B., Gorb, S.N., Kovalev, A., Lendlein, A., Neffe, A.T. %D 2011 %J The International Journal of Artificial Organs %N 2 %P 192-197 %R doi:10.5301/IJAO.2011.6394 %T Hyaluronic acid-based hydrogels crosslinked by copper-catalyzed azide-alkyne cycloaddition with tailorable mechanical properties %U https://doi.org/10.5301/IJAO.2011.6394 2 %X Biopolymers of the extracellular matrix are attractive starting materials for providing degradable and biocompatible biomaterials. In this study, hyaluronic acid-based hydrogels with tunable mechanical properties were prepared by the use of copper- catalyzed azide-alkyne cycloaddition (known as “click chemistry”). Alkyne-functionalized hyaluronic acid was crosslinked with linkers having two terminal azide functionalities, varying crosslinker density as well as the lengths and rigidity of the linker molecules. By variation of the crosslinker density and crosslinker type, hydrogels with elastic moduli in the range of 0.5-4 kPa were prepared. The washed materials contained a maximum of 6.8 mg copper per kg dry weight and the eluate of the gel crosslinked with diazidostilbene did not show toxic effects on L929 cells. The hyaluronic acid-based hydrogels have potential as biomaterials for cell culture or soft tissue regeneration applications. %0 conference lecture %@ %A Razzaq, M.Y., Behl, M., Lendlein, A. %D 2011 %J MRS Fall 2011 Meeting %T Shape-Memory Properties of Nanocomposites based on Poly(Omega-pentadecalactone) and Magnetic Nanoparticles %U %X %0 conference poster %@ %A Behl, M., Hiebl, B., Feng, Y., Lendlein, A. %D 2011 %J 13th CAST Annual Meeting, International Forum on Green Chemical Science & Engineering %T Biocompatibility of Degradable Shape-Memory Multiblock Copolymers with Polydepsipeptide- and Poly(ε-caprolactone)segments in vitro %U %X %0 conference poster %@ %A Neffe, A.T., Zaupa, A., Lendlein, A. %D 2011 %J 38th Congress of the European Society for Artificial Organs, ESAO 2011 %T Physical Crosslinking of Gelatin: A Supramolecular Approach to Biomaterials %U %X %0 conference lecture %@ %A Li, W., Ou, L., Wang, W., Liu, J., Sorg, H., Furlani, D., Gaebel, R., Mark, P., Klopsch, C., Wang, L., Luetzow, K., Lendlein, A., Wagner, K., Klee, D., Liebold, A., Li, R., Kong, D., Steinhoff, G., Ma, N. %D 2011 %J World Conference on Regenerative Medicine %T Matrigel could recruit stem cells for cardiac regeneration %U %X %0 conference poster %@ %A Luetzow, K., Weigel, T., Kosmalla, H.-J., Schossig, M., Kratz, K., Lendlein, A. %D 2011 %J Advanced Functional Polymers for Medicine, AFPM 2011 %T Preparation of Three-Dimensional Scaffolds from Degradable Poly(Ether)Esterurethane by Thermally Induced Phase Separation Technique %U %X %0 journal article %@ 1022-1360 %A Mathew, S., Lendlein, A., Wischke, C. %D 2011 %J Macromolecular Symposia %N 1 %P 123-133 %R doi:10.1002/masy.201100059 %T Degradation Behavior of Porous Copolyester Microparticles in the Light of Dynamic Changes in Their Morphology %U https://doi.org/10.1002/masy.201100059 1 %X The pore structures of microparticulate drug carriers are important diffusion pathways, which are not a static property but rather may be changing in the case of degradable matrix polymers such as poly[(rac-lactide)-co-glycolide] (PLGA). In this study, the mutual impacts of dynamic changes in microparticle porosity and polymer degradation were analyzed for PLGA with different molecular weights and end groups as well as PLGA-based triblock copolymers. In selected cases, particularly for PLGA with hydrophilic end groups and low initial number average molecular weight of 5 kDa, pore opening/pore closing phenomena were detected during incubation in phosphate buffer at 37 °C. Initially, pore closing was induced by water-induced plasticization and the reduction of interfacial tension. The pattern of molecular weight decrease and mass loss suggested that pore closing did not result in undesired autocatalytic acceleration of degradation or delayed mass loss due to trapped acidic degradation products. %0 conference lecture %@ %A Scharnagl, N., Wischke, C., Lendlein, A. %D 2011 %J 6. BMBF-Projektforum Biotechnologie, BIOTECHNICA 2011 %T Berlin-Brandenburg Center for Regenerative Therapies – BCRT, Polymer-based Biomaterials %U %X %0 conference lecture %@ %A Melchert, C., Behl, M., Lendlein, A. %D 2011 %J MRS Fall 2011 Meeting %T Phase Transition Behavior of Main Chain Nematic Liquid-Crystalline Polymers Based on 2-methyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone and 2-tert-butyl-1,4-bis[4-(4-pentenyloxy)benzoyl]hydroquinone %U %X %0 journal article %@ 1022-1360 %A Neffe, A.T., Kobuch, K.A., Maier, M., Feucht, N., Lohmann, C.P., Wolfstein, A., Streufert, D., Kamlage, S., Lendlein, A. %D 2011 %J Macromolecular Symposia %N 1 %P 229-235 %R doi:10.1002/masy.201100049 %T In vitro and in vivo Evaluation of a Multifunctional Hyaluronic acid based Hydrogel System for Local Application on the Retina %U https://doi.org/10.1002/masy.201100049 1 %X Conventional treatment of retinal detachment with laser and/or triamcinolon acetonide (TAAC) does not prevent loss of vision in all patients. Therefore, the development of degradable hydrogel patches covering retinal breaks was envisioned as alternative. Stable hydrogels could be formed by crosslinking hyaluronic acid with 1,2,3,4-diepoxybutane. Triamcinolone was diffusible in the gels. The hydrogels were slowly degrading, and mass loss during hydrolytic degradation was observed starting after three weeks. The sterilized gels showed excellent intraocular biocompatibility in vivo in rabbit eyes when applied as a patch on the retina. The good retinal adherence of the patch and absence of cellular growth and proliferation in and around the gel indicated the suitability as a material for a retinal patch to prevent cell-migration and proliferation after a retinal break and for local drug application. %0 conference poster %@ %A Iqbal, D., Melchert, C., Behl, M., Lendlein, A., Beuermann, S. %D 2011 %J MRS Fall 2011 Meeting %T Modeling of Free Radical Polymerization of Azobenzene-based Linear Polymers %U %X %0 conference poster %@ %A Yang, D., Feng, Y., Behl, M., Lendlein, A., Zhao, H., Khan, M., Guo, J. %D 2011 %J MRS Fall 2011 Meeting %T Biomimetic Hemo-compatible Surfaces of Polyurethane Obtained by PEG and MPC Grafted Copolymer Brushes %U %X %0 journal article %@ 1946-4274 %A Santan, H.D., Neffe, A.T., Kamlage, S., Lendlein, A. %D 2011 %J MRS Online Proceedings Library %P 226-233 %R doi:10.1557/opl.2012.703 %T Thermal Gelation and Stability of Pectin Grafted with PEPE %U https://doi.org/10.1557/opl.2012.703 %X Stimuli-sensitive materials can change properties upon exposure to an external stimulus. Thermoreversible gelation upon heating is one example for such a stimuli sensitivity. Here, it is of significance to tailor the tAransition temperature and to achieve large changes of G’ and the viscosity. Grafting of the thermosensitive poly(ethylene glycol-b-propylene glycol-b-ethylene glycol)s (PEPEs) to pectin was performed in order to investigate if tailoring of the sol-gel-transition temperature can be achieved by adjusting the grafting ratio. PEPEs were aminated and grafted to the polysaccharide via EDC coupling as shown by FTIR. The sol-gel transition of the pectin, PEPE, and the grafted system (PGP) was investigated by rheology. The gelation temperature (Tgel) of the system could be adjusted by varying the grafting density of PEPE onto pectin as well as by the concentration of the thermosensitive polymer in aqueous solution. A concentration of 15 – 20 wt% of the grafted system in water led to gelation temperatures in the range of 25 – 33 °C and the critical micelle concentration (CMC) and critical micelle temperature (CMT) of the grafted systems were determined by UV spectroscopy. The viscosity and the G’ increased by four orders of magnitudes at Tgel, which is comparable to PEPEs alone, but could be reached at lower PEPE concentrations. In the future, a thorough mechanistic investigation of the gelation process would be of interest. %0 conference poster %@ %A Santan, H.D., Neffe, A.T., Kamlage, S., Lendlein, A. %D 2011 %J MRS Fall 2011 Meeting, Symposium V %T Degradable Thermosensitive hydrogels based on grafted pectin or chondritin sulfate %U %X %0 journal article %@ 1022-1360 %A Schneider, T., Kohl, B., Sauter, T., Becker, T., Kratz, K., Schossig, M., Hiebl, B., Jung, F., Lendlein, A., Ertel, W., Schulze-Tanzil, G. %D 2011 %J Macromolecular Symposia %N 1 %P 28-39 %R doi:10.1002/masy.201100057 %T Viability, adhesion and differentiated phenotype of articular chondrocytes on degradable polymers and electro-spun structures thereof %U https://doi.org/10.1002/masy.201100057 1 %X Degradable polymers are essential to enable biomaterial-based regenerative therapies, particularly, in articular cartilage defect healing, which remains a major clinical challenge. The aim of this study was to investigate the effect of two degradable polymers (as a film or scaffold) on primary articular chondrocytes vitality, adherence, differentiated phenotype and morphology. Films and electro-spun scaffolds were prepared from degradable poly(ether)ester urethane (PDC), which was synthesized via co-condensation of poly(p-dioxanone)diol and poly(ε-caprolactone)diol with an aliphatic diisocyanate and poly(p-dioxanone) (PPDO). The thermal and mechanical properties and the surface roughness of the films and scaffolds were examined by differential scanning calorimetry, dynamic mechanical thermal analysis, tensile tests and optical profilometry. Primary porcine articular chondrocytes were seeded on the polymers and analysed for viability, ultrastructure (scanning electron microscopy) and immunolabelled for type II collagen. All films and scaffolds exhibited a low endotoxin load < 0.06 EU/ml and only moderate cytotoxic effects when tested with L929 cells. The results of the seeding experiments revealed that survival and adhesion of chondrocytes depended strongly on seeding density. Vital chondrocytes could be detected on both PPDO and PDC films and scaffolds. They produced the cartilage-specific protein type II collagen indicating differentiated functions. However, they exhibited a mixed morphology on the films and a more flattened cell shape on the scaffolds. The cell/biomaterial interaction in the PPDO scaffolds or films was more intense compared to that in PDC topologies. %0 journal article %@ 0391-3988 %A Schneider, T., Kohl, B., Sauter, T., Becker, T., Kratz, K., Schossig, M., Jung, F., Lendlein, A., Ertel, W., Schulze-Tanzil, G. %D 2011 %J The International Journal of Artificial Organs %N 8 %P 688 %R doi:10.5301/IJAO.2011.8702 %T Interaction of chondrocytes with electrospun polymer scaffolds depending on the fibre orientation %U https://doi.org/10.5301/IJAO.2011.8702 8 %X No abstract %0 conference poster %@ %A Federico, S., Lendlein, A., Neffe, A.T. %D 2011 %J Advanced Functional Polymers for Medicine, AFPM 2011 %T Supramolecular Networks formed by Biological Rcognition of Collagen and a Peptide Grafted to Hyaluronic Acid %U %X %0 journal article %@ 1022-1360 %A Roch, T., Pierce, B.F., Zaupa, A., Jung, F., Neffe, A.T.Lendlein, A. %D 2011 %J Macromolecular Symposia %N 1 %P 182-189 %R doi:10.1002/masy.201100048 %T Reducing the Endotoxin Burden of Desaminotyrosine- and Desaminotyrosyl tyrosine-Functionalized Gelatin %U https://doi.org/10.1002/masy.201100048 1 %X Biomaterial-induced autoregeneration requires materials with distinct tailored mechanical and thermal properties, water uptake and swelling properties as well as degradation behavior. Furthermore, before any biomaterial can be applied in vivo, in vitro studies should be performed that confirm the suitability for such applications. One facet in this process is the evaluation of endotoxin loads and immunogenic response to the material to avoid an unspecific activation of the immune system, which otherwise might cause fever and could lead to life–threatening pathologies. In this study, gelatins functionalized with desaminotyrosine (DAT) or desaminotyrosyl tyrosine (DATT) were investigated in terms of their endotoxin content and their potential to induce an inflammatory cytokine response in macrophages. Using the Limulus amebocyte lysate (LAL) test it could be shown that the endotoxin content was substantially reduced by using certified low endotoxin containing gelatin and performing the gelatin functionalization under cleanroom conditions. Furthermore, production of inflammatory cytokines such as interleukin 6 (IL-6) and tumor necrosis factor–alpha (TNFα) of an immune relevant macrophage cell line was significantly reduced for these materials. The survival of the macrophage cell line in the presence of DAT(T)-functionalized gelatins was not influenced by both materials. Therefore, DAT- and DATT-functionalized gelatins were shown to have passed the tests concerning immunological responses important for their applicability in vivo. %0 conference lecture %@ %A Wischke, C., Lendlein, A. %D 2011 %J Multifunktionelle polymere Hilfsstoffe, Jahrestagung der Deutschen Pharmazeutischen Gesellschaft und der Oesterreichischen Pharmazeutischen Gesellschaft 2011 %T Degradable shape-memory polymer networks as drug carriers %U %X %0 journal article %@ 1076-3279 %A Cui, J., Kratz, K., Hiebl, B., Jung, F., Lendlein, A. %D 2011 %J Tissue Engineering A %N 3-4 %P 531-584 %R doi:10.1089/ten.tea.2010.1502 %T Poly(n-butyl acrylate) networks with tailored mechanical properties designed as model substrates for mechano-responsive cells %U https://doi.org/10.1089/ten.tea.2010.1502 3-4 %X No abstract %0 conference lecture %@ %A Lendlein, A. %D 2011 %J Mini-Symposium National Center %T Active Biomaterials for Regenerative Medicine %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2011 %J Vortrag at the Hong Kong Polytechnic University, Institute of Textiles and Clothing %T Multifunctional-Shape Memory Polymers %U %X %0 conference lecture (invited) %@ %A Jung, F., Lendlein, A. %D 2011 %J 25. Sitzung des Ausschusses fuer Wissenschaft, Forschung und Kultur %T Ausseruniversitaere Forschungseinrichtungen in Brandenburg – Zusammenarbeit mit Wirtschaft und Hochschulen %U %X %0 conference lecture %@ %A Neffe, A.T., Zaupa, A., Lendlein, A. %D 2011 %J Bioorganik Symposium, Nachwuchsgruppenleitertreffen %T Gelatine mit definierten physikalischen Netzpunkten als Basis fuer supramolekulare, multifunktionale Biomaterialien %U %X %0 conference lecture %@ %A Neffe, A.T., Zaupa, A., Pierce, B.F., Lendlein, A. %D 2011 %J MRS Fall 2011 Meeting %T Knowledge-Based Design and Tailoring of Gelatin-Based Hydrogels by Functionalization with Tyrosine-Derived Groups %U %X %0 conference lecture %@ %A Jung, F., Neffe, A.T., Lendlein, A. %D 2011 %J 38th Congress of the European Society for Artificial Organs, ESAO 2011 %T Hemocompatibility Testing of Polymers and Hemo-/Histocompatible Polymers %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2011 %J Young European Biomaterial Scientists Designing a View for the Future, BioFuture 2011 %T Fundamental Principles for Designing Degradable Polymers %U %X %0 conference lecture %@ %A Lendlein, A. %D 2011 %J Natur- und ingenieurwissenschaftliches Kolleg %T Multifunktionale Materialien für die Biomedizin %U %X %0 journal article %@ 1076-3279 %A Kommareddy, K.P., Lange, C., Cui, J., Boergermann, J.H., Manjubala, I., Rumpler, M., Dunlop, J.W.C., Kratz, K., Lendlein, A., Knaus, P., Fratzl, P. %D 2011 %J Tissue Engineering A %N 3-4 %P 531-584 %R doi:10.1089/ten.tea.2010.1502 %T Three-dimensional tissue growth in polymer scaffolds with different stiffness and in-vitro influence of BMP-2 on tissue formation in hydroxyapatite scaffolds %U https://doi.org/10.1089/ten.tea.2010.1502 3-4 %X No abstract %0 conference lecture %@ %A Scharnagl, N., Wischke, C., Lendlein, A. %D 2011 %J Medica 2011 %T Berlin-Brandenburg Center for Regenerative Therapies – BCRT, Polymer-based Biomaterials %U %X %0 journal article %@ 1432-9778 %A Melchert, C., Behl, M., Lendlein, A. %D 2011 %J Photonik %N 5 %P 77 %T Lichtinduzierte Formaenderung in Polymeren %U 5 %X Photosensitive Formänderungs- und Formgedächtnis-Materialien reagieren auf Belichtung mit einer Veränderung ihrer vorgegebenen Form, die mittels einer Polymermatrix von der molekularen Nano-Skala auf die Makro-Ebene übersetzt wird. Damit ergeben sich vielversprechende Funktionsmaterialien z.B. für optische Sensoren und Aktoren von Mikrorobotern, optische Mikropinzetten oder Pumpen. Ausgehend von den molekularen Grundlagen erläutern wir Funktion, Eigenschaften und Anwendungen. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2011 %J MRS Fall 2011 Meeting %T Tailoring Degradable Polymers for Biofunctional Implants Inducing Tissue Regeneration %U %X %0 conference poster %@ %A Tripodo, G., Wischke, C., Lendlein, A. %D 2011 %J MRS Fall 2011 Meeting, Symposium V %T Design of semi-interpenetrating networks based on poly(ethyl-2-cyanoacrylate) and oligo(ethyleneglycol) diglycidyl ether %U %X %0 conference lecture %@ %A Wischke, C., Steuer, S., Lendlein, A. %D 2011 %J MRS Fall 2011 Meeting, Symposium V %T Determining loading kinetics of drug releasing degradable shape-memory polymers %U %X %0 conference lecture %@ %A Lendlein, A. %D 2011 %J Natur- und ingenieurwissenschaftliches Kolleg %T Multifunktionale Materialien für die Biomedizin - Vorstellung %U %X %0 conference lecture %@ %A Neffe, A.T., Pierce, B.F., Blaszkiewicz, J., Lendlein, A. %D 2011 %J MRS Fall 2011 Meeting, Symposium V %T Quantifying Protein Adsorption to Physically Crosslinked Gelatin-Based Networks %U %X %0 journal article %@ 1022-1360 %A Zotzmann, J., Behl, M., Lendlein, A. %D 2011 %J Macromolecular Symposia %N 1 %P 147-153 %R doi:10.1002/masy.201100039 %T The Influence of Programming Conditions on the Triple-Shape Effect of Copolymer Networks with Poly(Omega-pentadecalactone) and Poly(Epsilon-caprolactone) as Switching Segments %U https://doi.org/10.1002/masy.201100039 1 %X A versatile triple-shape material based on the two crystallizable segments poly(ω–pentadecalactone) and poly(ε-caprolactone) was synthesized showing triple-shape capability after application of the typical two-step triple-shape creation procedure at elevated temperatures (TSCP) as well as a one-step programming procedure at high temperature or at room temperature by cold drawing. By applying TSCP and varying the sequence of programming temperatures, the influence of the programming procedure on the triple-shape capability was investigated. The application of such a modified TSCP enabled to a certain extent the control of triple-shape capability by influencing the crystallization behavior of the two switching segments in these copolymer networks. %0 conference lecture %@ %A Piece, B.F., Neffe, A.T., Lendlein, A. %D 2011 %J MRS Fall 2011 Meeting, Symposium V %T Photocrosslinked Co-Networks from Glycidylmethacrylated Gelatin and Poly(ethylene glycol) (Di)Methacrylates %U %X %0 conference poster %@ %A Mathew, S., Wischke, C., Lendlein, A. %D 2011 %J Advanced Functional Polymers for Medicine, AFPM 2011 %T Degradation behaviour of porous co-polyester microparticles in the light of dynamic changes in their morphology %U %X %0 conference lecture %@ %A Behl, M., Zotzmann, J., Feng, Y., Lendlein, A. %D 2011 %J MRS Fall 2011 Meeting %T Triple-Shape Effect of Copolymer Networks %U %X %0 conference lecture (invited) %@ %A Behl, M., Zotzmann, J., Kratz, K., Feng, Y., Lendlein, A. %D 2011 %J Vortrag at the Hong Kong Polytechnic University, Institute of Textiles and Clothing %T Triple-Shape Polymers %U %X %0 journal article %@ 1386-0291 %A Mayer, A., Kratz, K., Hiebl, B., Lendlein, A., Jung, F. %D 2011 %J Clinical Hemorheology and Microcirculation %N 1-4 %P 423-430 %R doi:10.3233/CH-2011-1492 %T Support of HUVEC proliferation by pro-angiogenic intermediate CD163+ monocytes/macrophages: A co-culture experiment %U https://doi.org/10.3233/CH-2011-1492 1-4 %X So called intermediate (MO2) monocytes/macrophages possess anti-inflammatory properties and express the MO lineage marker CD163. On a hydrophilic, acrylamide-based hydrogel human intermediate (CD14++ CD16+) CD163++ monocytes/macrophages (aMO2) which were angiogenically stimulated, maintained a pro-angiogenic and non-inflammatory status for at least 14 days. Here we explored, whether this aMO2 subset can positively influence the proliferation of human umbilical venous endothelial cells (HUVECs) without switching back into a pro-inflammatory (MO1) phenotype. aMO2 or HUVEC were seeded alone on glass cover slips (0.5 × 105 cells / 1.33 cm2) in a HUVEC specific cell culture medium (EGM-2) for 3 hrs, 24 hrs and 72 hrs or under co-culture conditions (0.5 × 105 HUVEC + 0.25 × 105 aMO2 / 1.33 cm2) in EGM-2 for the same time window as well (n = 6 each). Under co-culture conditions the numbers of adherent HUVEC per unit area were significantly higher (p < 0.01; 525 ± 52 HUVEC/mm2) compared to control mono-cultures (473 ± 76 HUVEC/mm2) after 72 hrs of cultivation and showed their typically spread morphology. The aMO2 remained in their subset status and secreted VEGF-A165 without release of pro-inflammatory cytokines until the end of the 72 hrs cultivation time period, thereby supporting the HUVEC proliferation. These in vitro results might indicate that this MO subset can be used as cellular delivery system for pro-angiogenic and non-inflammatory mediators to support the endothelialisation of biomaterials like e.g. cPnBA. %0 book part %@ %A Behl, M., Zotzmann, J., Schroeter, M., Lendlein, A. %D 2011 %J Handbook of Biodegradable Polymers: Synthesis, Characterization and Applications %P 195-215 %T Biodegradable Shape-Memory Polymers %U %X %0 journal article %@ 1946-4274 %A Neffe, A.T., Pierce, B.F., Blaszkiewicz, J., Lendlein, A. %D 2011 %J MRS Online Proceedings Library %P 196-201 %R doi:10.1557/opl.2012.476 %T Quantifying Protein Adsorption to Physically Crosslinked Gelatin-Based Networks %U https://doi.org/10.1557/opl.2012.476 %X Physically crosslinked hydrogels based on gelatin functionalized with desaminotyrosine (DAT) (giving Gel-DAT) or desaminotyrosyl tyrosine (DATT) (resulting in Gel-DATT) have shown high potential as biomaterials. Here, protein adsorption to the functionalized gelatins in comparison to gelatin was quantified to see if the functionalization and chain organization of gelatins has an influence on the amount of proteins being adsorbed. For this purpose, gelatin, Gel-DAT, and Gel-DATT were incubated with water or aq. solutions of bovine serum albumin (BSA), fibrinogen, or fibronectin, respectively, at physiological concentrations. Protein concentrations in the supernatant were determined with the bicinchoninic acid (BCA) assay before and after the contact. BSA adsorption to the materials was influenced as well by the hydrophobicity of the material as the degree of swelling, with the observation that higher protein concentrations led to lower protein adsorption. The highest amount of fibronectin was adsorbed to Gel-DAT, followed by gelatin and Gel-DATT, with only small differences for different initial protein concentrations. Fibrinogen adsorption increased with increasing concentration. In the future, adsorption studies based on specific antibody-based techniques might enable quantification of the proteins also in competition assays and direct quantification of adsorbed material. %0 conference lecture %@ %A Wischke, C., Lendlein, A. %D 2011 %J MRS Fall 2011 Meeting %T Degradable shape-memory polymer networks as drug carriers %U %X %0 conference lecture %@ %A Zotzmann, J., Behl, M., Lendlein, A. %D 2011 %J MRS Fall 2011 Meeting, Symposium V %T Triple-Shape Effect of Copolymer Networks Based on Poly(Omega-pentadecalactone) and Poly(Epsilon-caprolactone) Segments Applying a Programming Procedure with an Adjusted Temperature Profile %U %X %0 journal article %@ 1946-4274 %A Tripodo, G., Wischke, C., Lendlein, A. %D 2011 %J MRS Online Proceedings Library %P 25-30 %R doi:10.1557/opl.2012.223  %T Design of semi-interpenetrating networks based on poly(ethyl-2-cyanoacrylate) and oligo(ethyleneglycol) diglycidyl ether %U https://doi.org/10.1557/opl.2012.223  %X The synthesis of semi-interpenetrating networks (SIPN) based on linear poly(ethyl 2-cyanoacrylate) (PECA) and oligo(ethylene glycol) diglycidyl ether (OEGDG) based polymer networks was motivated by the hypothesis that the brittleness of polycyanoacrylates may be overcome by incorporating them into a polymer network architecture. A sequential synthetic route was applied, in which first PECA was prepared by anionic polymerization. Subsequently, OEGDG was crosslinked with different anhydrides and curing catalysts to form networks with hydrolyzable ester bonds and interpenetrating PECA. These SIPNs showed a low water uptake compared to other polyether based networks. Some of the obtained materials were transparent and exhibited a great flexibility, which was maintained also after 24 h of immersion in water and subsequent drying. Such networks could be components of future stimuli-sensitive material systems. %0 journal article %@ 1616-5187 %A Wischke, C., Tripodo, G., Choi, N.-Y., Lendlein, A. %D 2011 %J Macromolecular Bioscience %N 12 %P 1637-1646 %R doi:10.1002/mabi.201100226 %T Hydrolytic Degradation Behavior of Poly(rac-lactide)-block-poly(propylene glycol)-block-poly(rac-lactide) Dimethacrylate Derived Networks Designed for Biomedical Applications %U https://doi.org/10.1002/mabi.201100226 12 %X For polymer-based degradable implants, mechanical performance and degradation behavior need to be precisely controlled. Based on a rational design, this work comprehensively describes the properties of photo-crosslinked polymer networks prepared from poly(rac-lactide)-block-poly(propylene glycol)-block-poly(rac-lactide) dimethacrylate precursors during degradation. By varying the length of poly(rac-lactide) blocks connected to a central 4 kDa polyether block, microphase separated networks with adjustable crosslinking density, hydrophilicity/hydrophobicity ratio, thermal, and mechanical properties are obtained. The materials are characterized by a low water uptake, controlled mass loss, and slowly decreasing wet-state E moduli in the kPa range. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2011 %J 13th CAST Annual Meeting, International Forum on Green Chemical Science & Engineering %T Shape-memory Polymers Based on Biodegradable Polymers %U %X %0 conference lecture %@ %A Wischke, C., Lendlein, A. %D 2011 %J MRS Fall 2011 Meeting %T Design aspects for drug releasing degradable shape-memory polymers %U %X %0 editorial %@ 0959-9428 %A Lendlein, A. %D 2010 %J Journal of Materials Chemistry %N 17 %P 3332-3334 %R doi:10.1039/c004361n %T Editorial: Progress in actively moving polymers %U https://doi.org/10.1039/c004361n 17 %X No abstract %0 conference paper %@ %A Rickert, D., Fuhrmann, R., Hiebl, B., Lendlein, A., Franke, R.-P. %D 2010 %J Advances in Regenerative Medicine: Role of Nanotechnology, and Engineering Principles, NATO Science for Peace and Security Series A: Chemistry and Biology, Proceedings of the NATO Advanced Research Workshop on Nanoengineered Systems for Regenerative Medicine %P 285-300 %R doi:10.1007/978-90-481-8790-4 %T Results of Biocompatibility Testing of Novel, Multifunctional Polymeric Implant Materials In-Vitro and In-Vivo %U https://doi.org/10.1007/978-90-481-8790-4 %X Extensive in vitro and in vivo evaluation of the biocompatibility of biomaterials intended for clinical applications is necessary to provide informationon the interactions that take place between the organism and these materials under specific implant conditions. Sterilization of polymer-based implant materials is a basic requirement but can lead to their damage or destruction. Low-temperature plasma (LTP) or ethylene oxide (EO) sterilization are objects of intensive research and were applied on the materials used in this program. After 4 weeks of polymer incubation in cell culture medium, samples, sterilized by LTP, gave a markedly higher mean cell lysis rate (3.7 ± 2.5%) than EO sterilized samples (0.9 ± 0.3%). To achieve relevant in vitro results on biomaterial-cell interactions, biocompatibility testing was carried out with cultures of locotypical cells, e.g. cells of the upper aerodigestive tract (ADT). Primary cell cultures of the oral cavity, the pharynx and the esophagus showed region-typical varying relationships between epithelial, fibroblastic and smooth muscle cells. Proper wound healing is thought to be required for the integration of biomaterials and angiogenesis is a prerequisite for this process. A focus of the present work was the influence of polymer-based implant materials and their degradation products on angiogenesis in vivo. After 48 h, none of the polymer samples demonstrated development of an avascular region in the chorioallantoic membrane (CAM) test. A key process in proper wound healing is the tightly controlled degradation and regeneration of the extracellular matrix (ECM). Matrix metalloproteinases (MMP’s) cleave the components of the ECM and are specifically inhibited by tissue inhibitors of matrix metalloproteinases (TIMP’s). Well balanced MMP and TIMP activities are important for the functionality of the ECM. The kinetics of MMP-1, MMP-2 and TIMP activity of oral and pharyngeal cells demonstrated similar surface dependent patterns. The same contrast in surface dependent MMP and TIMP activity levels was not found for esophageal cells. A biomaterial for the reconstruction of the upper ADT is subjected to varying pH values and enzymatic, bacterial and mechanical stress during the digestive and the swallowing process. These complex conditions can currently only be investigated in vivo in an animal model. As a model the stomach of the rat was selected, in which a biomaterial can be investigated under extreme chemical, enzymatic, bacteriological and mechanical conditions. Other parameters investigated are the impermeability of the polymer tissue closure and the tissue regeneration after defect reconstruction. The fluid tight integration of a long term resorbable AB copolymer network in the surrounding tissue of the gastric wall of Sprague Dawley rats could be demonstrated. %0 journal article %@ 0959-9428 %A Ganesan, R., Kratz, K., Lendlein, A. %D 2010 %J Journal of Materials Chemistry %P 7322-7331 %R doi:10.1039/b926690a %T Multicomponent protein patterning of material surfaces %U https://doi.org/10.1039/b926690a %X Micro- and nano-scale protein patterns have gained significant technological interest. While certain techniques for single-component protein patterning are well-established, multicomponent protein patterning approaches are a current topic of intensive research, which might enable complex biosensor systems and expand the knowledge in protein-protein and protein-cell or cell-cell interactions. Only a few patterning methods are suitable for the realization of three dimensional patterns, which are essential for many applications e.g. in the design of scaffolds for regenerative therapies. In this feature article representative approaches for creating multicomponent protein patterning are presented and their potential for tailoring microenvironments for cells on biomaterials surfaces is discussed. %0 journal article %@ 1743-4440 %A Lendlein, A., Behl, M., Hiebl, B., Wischke, C. %D 2010 %J Expert Review of Medical Devices %N 3 %P 357-379 %R doi:10.1586/ERD.10.8 %T Shape-memory polymers as a technology platform for biomedical applications %U https://doi.org/10.1586/ERD.10.8 3 %X Polymeric materials are clinically required for medical devices, as well as controlled drug delivery systems. Depending on the application, the polymer has to provide suitable functionalities, for example, mechanical functions or the capability to actively move, so that an implant can be inserted in a compact shape through key-hole incisions and unfold to its functional shape in the body. Shape-memory polymers, as described herein regarding their general principle, compositions and architectures, have developed to a technology platform that allows the tailored design of such multifunctionality. In this way, defined movements of implants triggered either directly or indirectly, tailored mechanical properties, capability for sterilization, biodegradability, biocompatibility and controlled drug release can be realized. This comprehensive review of the scientific and patent literature illustrates that this technology enables the development of novel medical devices that will be clinically evaluated in the near future. %0 journal article %@ 1559-4106 %A Kommareddy, K.P., Lange, C., Rumpler, M., Dunlop, J.W.C., Manjubala, I., Cui, J., Kratz, K., Lendlein, A., Fratzl, P. %D 2010 %J Biointerphases %N 2 %P 45 %R doi:10.1116/1.3431524 %T Two stages in three-dimensional in vitro growth of tissue generated by osteoblastlike cells %U https://doi.org/10.1116/1.3431524 2 %X Bone regeneration is controlled by a variety of biochemical, biomechanical, cellular, and hormonal mechanisms. In particular, physical properties of the substrate such as stiffness and architecture highly influence the proliferation and differentiation of cells. The aim of this work is to understand the influence of scaffold stiffness and cell seeding densities on the formation of tissue by osteoblast cells within polyether urethane scaffolds containing pores of different sizes. MC3T3-E1 preosteoblast cells were seeded on the scaffold, and the amount of tissue formed within the pores was analyzed for culture times up to 49 days by phase contrast microscopy. The authors show that the kinetics of three-dimensional tissue growth in these scaffolds follows two stages and can be described by a universal growth law. The first stage is dominated by cell-material interactions with cell adherence and differentiation being strongly dependent on the polymer material. After a delay time of a few weeks, cells begin to grow within their own matrix, the delay being strongly dependent on substrate stiffness and seeding protocols. In this later stage of growth, three-dimensional tissue amplification is controlled rather by the pore geometry than the scaffold material properties. This emphasizes how geometric constraints may guide tissue formation in vitro and shows that optimizing scaffold architectures may improve tissue formation independent of the scaffold material used. %0 journal article %@ 0964-1726 %A Cui, J., Kratz, K., Lendlein, A. %D 2010 %J Smart Materials and Structures %N 6 %P 065019 %R doi:10.1088/0964-1726/19/6/065019 %T Adjusting shape-memory properties of amorphous polyether urethanes and radio-opaque composites thereof by variation of physical parameters during programming %U https://doi.org/10.1088/0964-1726/19/6/065019 6 %X Various composites have been prepared to improve the mechanical properties of shape-memory polymers (SMPs) or to incorporate new functionalities (e.g. magneto-sensitivity) in polymer matrices. In this paper, we systematically investigated the influence of the programming temperature Tprog and the applied strain εm as parameters of the shape-memory creation procedure (SMCP) on the shape-memory properties of an amorphous polyether urethane and radio-opaque composites thereof. Recovery under stress-free conditions was quantified by the shape recovery rate Rr and the switching temperature Tsw, while the maximum recovery stress σmax was determined at the characteristic temperature Tσ, max under constant strain conditions. Excellent shape-memory properties were achieved in all experiments with Rr values in between 80 and 98%. σmax could be tailored from 0.4 to 3.7 MPa. Tsw and Tσ, max could be systematically adjusted from 33 to 71 °C by variation of Tprog for each investigated sample. The investigated radio-opaque shape-memory composites will form the material basis for mechanically active scaffolds, which could serve as an intelligent substitute for the extracellular matrix to study the influence of mechanical stimulation of tissue development. %0 book part %@ %A Madbouly, S.A., Lendlein, A. %D 2010 %J Advances in Polymer Science - Shape-memory Polymers %P 41-96 %R doi:10.1007/12_2009_28 %T Shape-Memory Polymer Composites %U https://doi.org/10.1007/12_2009_28 %X The development of shape-memory polymer composites (SMPCs) enables high recovery stress levels as well as novel functions such as electrical conductivity, magnetism, and biofunctionality. In this review chapter the substantial enhancement in mechanical properties of shape-memory polymers (SMPs) by incorporating small amounts of stiff fillers will be highlighted exemplarily for clay and polyhedral oligomeric silsesquioxanes (POSS). Three different functions resulting from adding functional fillers to SMP-matrices will be introduced and discussed: magnetic SMPCs with different types of magnetic nanoparticles, conductive SMPCs based on carbon nanotubes (CNTs), carbon black (CB), short carbon fiber (SCF), and biofunctional SMPCs containing hydroxyapatite (HA). Indirect induction of the shape-memory effect (SME) was realized for magnetic and conductive SMPCs either by exposure to an alternating magnetic field or by application of electrical current. Major challenges in design and fundamental understanding of polymer composites are the complexity of the composite structure, and the relationship between structural parameters and properties/functions, which is essential for tailoring SMPCs for specific applications. Therefore the novel functions and enhanced properties of SMPCs will be described considering the micro-/nanostructural parameters, such as dimension, shape, distribution, volume fraction, and alignment of fillers as well as interfacial interaction between the polymer matrix and dispersed fillers. Finally, an outlook is given describing the future challenges of this exciting research field as well as potential applications including automotive, aerospace, sensors, and biomedical applications. %0 conference paper %@ %A Lendlein, A., Behl, M., Kamlage, S. %D 2010 %J Advances in Regenerative Medicine: Role of Nanotechnology, and Engineering Principles, NATO Science for Peace and Security Series A: Chemistry and Biology, Proceedings of the NATO Advanced Research Workshop on Nanoengineered Systems for Regenerative Medicine %P 131-156 %R doi:10.1007/978-90-481-8790-4 %T The Nature of the Thermal Transition Influences the Shape-Memory Behavior of Polymer Networks %U https://doi.org/10.1007/978-90-481-8790-4 %X The contributions to this book, all written by leading experts in their respective disciplines, describe and explore the various facets of regenerative medicine and highlight the role of the "the nano length scale" and of "nano-scale systems" in defining and controlling cell and tissue environments. The development of novel tissue-regeneration strategies requires the integration of new insights emerging from studies of cell-matrix interactions, cellular signalling processes, and developmental and systems biology, into biomaterials design, ideally via a systems approach. The chapters cover a wide spectrum of topics ranging from stem cell biology, developmental biology, cell-matrix interactions, and matrix biology to surface science, materials processing and drug delivery. The book will be an especially valuable resource for researchers developing regenerative medicine paradigms that combine these facets into clinically translatable solutions. %0 journal article %@ 0883-7694 %A Shastri, V.P., Lendlein, A. %D 2010 %J MRS Bulletin %N 8 %P 571-575 %R doi:10.1557/mrs2010.524 %T Introductory Article: Engineering Materials for Regenerative Medicine %U https://doi.org/10.1557/mrs2010.524 8 %X presents the current state of this challenge in the implementation of regenerative therapies. %0 editorial %@ 0935-9648 %A Lendlein, A., Shastri, V.P. %D 2010 %J Advanced Materials %N 31 %P 3344-3347 %R doi:10.1002/adma.201002520 %T Editorial: Stimuli-Sensitive Polymers %U https://doi.org/10.1002/adma.201002520 31 %X No abstract %0 journal article %@ 0883-7694 %A Jung, F., Wischke, C., Lendlein, A. %D 2010 %J MRS Bulletin %N 8 %P 607-613 %T Degradable, Multifunctional Cardiovascular Implants: Challenges and Hurdles %U 8 %X Polymer-coated and polymer-based cardiovascular implants are essential constituents of modern medicine and will proceed to gain importance with the demographic changes toward a society of increasing age-related morbidity. Based on the experiences with implants such as coronary or peripheral stents, which are presently widely used in clinical medicine, several properties of the next generation of cardiovascular implants have been envisioned that could be fulfilled by multifunctional polymers. The challenge is to combine tailored mechanical properties and rapid endothelialization with controlled drug release in order to modulate environmental cells and tissue. Additionally, degradability and sensitivity to external stimuli are useful in several applications. A critical function in terms of clinical complications is the hemocompatibility. The design of devices with improved hemocompatibility requires advanced in vitro test setups as discussed in depth in this article. Finally, degradable, multifunctional shape-memory polymers are introduced as a promising family of functional polymers that fulfill several requirements of modern implants and are of high relevance for cardiovascular application (e.g., stent technology). Such multifunctional polymers are a technology platform for future cardiovascular implants enabling induced autoregeneration in regenerative therapies. %0 editorial %@ 1022-1336 %A Lendlein, A., Rehahn, M., Buchmeiser, M.R., Haag, R. %D 2010 %J Macromolecular Rapid Communications %P 1487-1491 %R doi:10.1002/marc.201000426 %T Editorial: Polymers in Biomedicine and Electronics %U https://doi.org/10.1002/marc.201000426 %X No abstract %0 conference paper %@ %A Luetzow, K., Neffe, A., Lendlein, A. %D 2010 %J Medical Device Materials V, Proceedings from the Materials Processes for Medical Devices Conference, MPMD 2009 %P 169-174 %T Developing Cell Selectivities of Acrylonitrile Based Copolymers and Porous Bodies from Poly(ether imide) %U %X %0 conference paper %@ %A Lendlein, A., Behl, M. %D 2010 %J Medical Device Materials V, Proceedings from the Materials Processes for Medical Devices Conference, MPMD 2009 %P 100-104 %T Active Biomaterials %U %X %0 journal article %@ 1022-1336 %A Wagermaier, W., Zander, T., Hofmann, D., Kratz, K., Kumar, U.N., Lendlein, A. %D 2010 %J Macromolecular Rapid Communications %N 17 %P 1546-1553 %R doi:10.1002/marc.201000122 %T In Situ X-Ray Scattering Studies of Poly(Epsilon-caprolactone) Networks with Grafted Poly(ethylene glycol) Chains to Investigate Structural Changes during Dual- and Triple-Shape Effect %U https://doi.org/10.1002/marc.201000122 17 %X The dual- and triple-shape effects of multiphase polymer networks that contain two crystallizable chain segments have been assessed in situ by combining X-ray measurements with thermomechanical investigations. The studied polymer, named CLEG, is a multiphase polymer network of crystallizable poly(ε-caprolactone) (PCL) with grafted poly(ethylene glycol) (PEG) side chains. Wide-angle (WAXS) and small-angle X-ray scattering (SAXS) measurements were combined with temperature-controlled in situ tensile testing experiments. This integrated approach enables systematic investigation and interpretation of relevant structural features during the programming procedures and the thermally-induced recovery process. Main results concern the combined effect of PCL and PEG crystals on shape fixation, the specific role of low-melting PCL crystallites in the fixation of the low temperature temporary shape, and the different orientation behavior of PCL and PEG crystals during certain stages of the programming procedure. These results demonstrate that crystal orientation effects are dominant for the PCL crystals. The effects of the low temperature PCL crystals could only be investigated when synchrotron radiation was applied. These findings indicate the great potential of in situ X-ray investigations for the creation of design-relevant knowledge about the microscopic foundations of dual- and triple-shape effects in appropriate polymer systems. %0 journal article %@ 0959-9428 %A Tronci, G., Neffe, A.T., Pierce, B.F., Lendlein, A. %D 2010 %J Journal of Materials Chemistry %N 40 %P 8875-8884 %R doi:10.1039/C0JM00883D %T An Entropy–Elastic Gelatin-based Hydrogel System %U https://doi.org/10.1039/C0JM00883D 40 %X Gelatin is a non-immunogenic and degradable biopolymer, which is widely applied in the biomedical field e.g. for drug capsules or as absorbable hemostats. However, gelatin materials present limited and hardly reproducible mechanical properties especially in aqueous systems, particularly caused by the uncontrollable partial renaturation of collagen-like triple helices. Therefore, mechanically demanding applications for gelatin-based materials, such as vascular patches, i.e. hydrogel films that seal large incisions in vessel walls, and for induced autoregeneration, are basically excluded if this challenge is not addressed. Through the synthesis of a defined chemical network of gelatin with hexamethylene diisocyanate (HDI) in DMSO, the self-organization of gelatin chains could be hindered and amorphous gelatin films were successfully prepared having Young's moduli of 60–530 kPa. Transferring the crosslinking reaction with HDI and, alternatively, ethyl lysine diisocyanate (LDI), to water as reaction medium allowed the tailoring of swelling behaviour and mechanical properties by variation of crosslinker content while suppressing the formation of helices. The hydrogels had Young's moduli of 70–740 kPa, compressive moduli of 16–48 kPa, and degrees of swelling of 300–800 vol%. Test reactions investigated by ESI mass spectrometry allowed the identification and quantification of reaction products of the crosslinking reaction. The HDI crosslinked networks were stabilized by direct covalent crosslinks (ca. 10 mol%), supported by grafting (50 mol%) and blending of hydrophobic oligomeric chains. For the LDI-based networks, less crosslinked (3 mol%) and grafted species (5 mol%) and much higher amounts of oligomers were observed. The adjustable hydrogel system enables the application of gelatin-based materials in physiological environments. %0 journal article %@ 0959-9428 %A Kumar, U.N., Kratz, K., Wagermaier, W., Behl, M., Lendlein, A. %D 2010 %J Journal of Materials Chemistry %N 17 %P 3404-3415 %R doi:10.1039/b923000a %T Non-contact actuation of triple-shape effect in multiphase polymer network nanocomposites in alternating magnetic field %U https://doi.org/10.1039/b923000a 17 %X Triple-shape polymers (TSP) can memorize two independent shapes, which are recovered when the temperature is subsequently increased. Certain applications do not allow triggering of the triple-shape effect (TSE) by environmental heating (e.g. potential damaging of surrounding tissue) and therefore require a non-contact activation. Here we explored whether polymer nanocomposites can be designed, which enable non-contact activation of TSE in an alternating magnetic field. %0 journal article %@ 1386-0291 %A Cui, J., Trescher, K., Kratz, K., Jung, F., Hiebl, B., Lendlein, A. %D 2010 %J Clinical Hemorheology and Microcirculation %N 2-4 %P 401-411 %R doi:10.3233/CH-2010-1322 %T Melt-processable hydrophobic acrylonitrile-based copolymer systems with adjustable elastic properties designed for biomedical applications %U https://doi.org/10.3233/CH-2010-1322 2-4 %X Acrylonitrile-based polymer systems (PAN) are comprehensively explored as versatile biomaterials having various potential biomedical applications, such as membranes for extra corporal devices or matrixes for guided skin reconstruction. The surface properties (e.g. hydrophilicity or charges) of such materials can be tailored over a wide range by variation of molecular parameters such as different co-monomers or their sequence structure. Some of these materials show interesting biofunctionalities such as capability for selective cell cultivation. So far, the majority of AN-based copolymers, which were investigated in physiological environments, were processed from the solution (e.g. membranes), as these materials are thermo-sensitive and might degrade when heated. In this work we aimed at the synthesis of hydrophobic, melt-processable AN-based copolymers with adjustable elastic properties for preparation of model scaffolds with controlled pore geometry and size. For this purpose a series of copolymers from acrylonitrile and n-butyl acrylate (nBA) was synthesized via free radical copolymerisation technique. The content of nBA in the copolymer varied from 45 wt% to 70 wt%, which was confirmed by 1H-NMR spectroscopy. The glass transition temperatures (Tg) of the P(AN-co-nBA) copolymers determined by differential scanning calorimetry (DSC) decreased from 58°C to 20°C with increasing nBA-content, which was in excellent agreement with the prediction of the Gordon-Taylor equation based on the Tgs of the homopolymers. The Young’s modulus obtained in tensile tests was found to decrease significantly with rising nBA-content from 1062 MPa to 1.2 MPa. All copolymers could be successfully processed from the melt with processing temperatures ranging from 50°C to 170°C, whereby thermally induced decomposition was only observed at temperatures higher than 320°C in thermal gravimetric analysis (TGA). Finally, the melt processed P(AN-co-nBA) biomaterials were sterilized with ethylene oxide and tested for cytotoxicity in direct contact tests with L929 cells according to the EN DIN ISO standard 10993-5. All tested samples exhibited non-toxic effects on the functional integrity of the cell membrane and the mitochondrial activity. However, the morphology of the cells on the samples was different from that observed on polystyrene as control, indicating slightly cytotoxic effects according to the evaluation guide of the US Pharmacopeial Convention. Thus, the melt-processable, hydrophobic P(AN-co-nBA) copolymers with adjustable mechanical properties are promising candidates for in vitro investigations of tissue growth kinetics. %0 conference lecture (invited) %@ %A Hofmann, D., Entrialgo, M., Reiche, J., Kratz, K., Lendlein, A. %D 2010 %J 9th International Conference Medical Applications of Novel Biomaterials and Nano-Biotechnology, CIMTEC 2010 %T Molecular Modeling and experimental investigation of hydrolytically degradable polymeric biomaterials %U %X %0 conference poster %@ %A Reiche, J., Kratz, K., Hofmann, D., Lendlein, A. %D 2010 %J 13th International Conference on Organized Molecular Films LB-13 %T Separation of chain scission kinetics and water diffusion involved in polymer hydrolytic / enzymatic degradation based on monolayer experiments %U %X %0 conference poster %@ %A Pierce, B., Bellin, K., Behl, M., Lendlein, A. %D 2010 %J Biodegradable Polymers as Biomaterials, 459th WE-Heraeus-Seminar %T Solvent- and Thermally-Induced Shape-Memory Effect of Polymer Networks Based on Poly[(rac-lactide)-co-glycolide] %U %X %0 journal article %@ 0959-9428 %A Behl, M., Lendlein, A. %D 2010 %J Journal of Materials Chemistry %P 3335-3345 %R doi:10.1039/b922992b %T Triple-shape polymers %U https://doi.org/10.1039/b922992b %X Shape-memory polymers (SMPs) are an emerging class of active materials, which are able to change their shape in a predefined way upon appropriate stimulation. As SMPs can switch from a temporary to their permanent shape they are dual-shape materials. Recently, multiphase polymer networks were explored, which are able to switch from a first shape (A) to a second shape (B) and from there to a third shape (C). Here we highlight this triple-shape effect (TSE) as a thermally triggered effect. The generality of the concept will be explained by describing suitable polymer network architectures and appropriate triple-shape creation processes (TSCPs). TSCP is a thermomechanical treatment typically consisting of two consecutive deformation steps resulting in shapes B and A. The molecular architecture of triple-shape polymers (TSPs) also contains the essential elements for the dual-shape effect (DSE), which therefore was systematically investigated. The understanding of the underlying mechanisms recently led to the discovery of a system, where a thermomechanical treatment with only one single deformation step resulted in a TSE. TSPs enable complex, active deformations on demand, having a high potential as enabling technology for application fields including intelligent medical devices, textile and assembling systems. %0 journal article %@ 1022-1352 %A Neffe, A.T., Tronci, G., Alteheld, A., Lendlein, A. %D 2010 %J Macromolecular Chemistry and Physics %N 2 %P 182-194 %R doi:10.1002/macp.200900441 %T Controlled Change of Mechanical Properties during Hydrolytic Degradation of Polyester Urethane Networks %U https://doi.org/10.1002/macp.200900441 2 %X Polyester urethane networks are versatile polymer systems as it is possible to tailor their mechanical properties and their hydrolytic degradation profile. For biomedical applications, the biodegradability as well as the thermomechanical properties of the polymer networks during the course of degradation is of importance. Therefore, we investigated the change of thermomechanical properties of networks based on star-shaped precursors of rac-dilactide and diglycolide, -caprolactone, or p-dioxanone, respectively, during hydrolytic degradation. Degradation rate and mechanical properties of the polymer networks were tailored by crosslink density, comonomers, and by changing the glass transition temperature. Most importantly, the degradation of the networks led to a controlled, step-by-step change of the mechanical properties of the networks. %0 book part %@ %A Behl, M., Zotzmann, J., Lendlein, A. %D 2010 %J Advances in Polymer Science - Shape-memory Polymers %P 1-40 %R doi:10.1007/12_2009_26 %T Shape-Memory Polymers and Shape-Changing Polymers %U https://doi.org/10.1007/12_2009_26 %X The ability of polymers to respond to external stimuli is of high scientific and technological significance. In the last few years, research activities have been intensified substantially, exploring whether stimuli-sensitive polymers can be designed that move actively. In this review actively-moving materials were classified according to the underlying mechanisms enabling the shape changes: shape-memory polymers and shape-changing polymers / shape-changing gels were identified. The application spectra of these materials as well as the current developments were elucidated and general molecular design principles presented. When applicable, a further distinction according to the applied stimulus was made. %0 journal article %@ 0935-9648 %A Behl, M., Razzaq, M.Y., Lendlein, A. %D 2010 %J Advanced Materials %N 31 %P 3388-3410 %R doi:10.1002/adma.200904447 %T Multifunctional Shape-memory Polymers %U https://doi.org/10.1002/adma.200904447 31 %X The thermally-induced shape-memory effect (SME) is the capability of a material to change its shape in a predefined way in response to heat. In shape-memory polymers (SMP) this shape change is the entropy-driven recovery of a mechanical deformation, which was obtained before by application of external stress and was temporarily fixed by formation of physical crosslinks. The high technological significance of SMP becomes apparent in many established products (e.g., packaging materials, assembling devices, textiles, and membranes) and the broad SMP development activities in the field of biomedical as well as aerospace applications (e.g., medical devices or morphing structures for aerospace vehicles). Inspired by the complex and diverse requirements of these applications fundamental research is aiming at multifunctional SMP, in which SME is combined with additional functions and is proceeding rapidly. In this review different concepts for the creation of multifunctionality are derived from the various polymer network architectures of thermally-induced SMP. Multimaterial systems, such as nanocomposites, are described as well as one-component polymer systems, in which independent functions are integrated. Future challenges will be to transfer the concept of multifunctionality to other emerging shape-memory technologies like light-sensitive SMP, reversible shape changing effects or triple-shape polymers. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2010 %J Biomaterials, 2. Kolloquium des Laboratoriums fuer Materialforschung (LaMa) %T Polymers for Biomedical Applications %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2010 %J Nanosciences Workshop %T Active Biomaterials %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2010 %J 6th Swiss Experimental Surgery Symposium, SESS 2010 %T Polymers for Tissue Engineering %U %X %0 journal article %@ 0168-1656 %A Hiebl, B., Luetzow, K., Lange, M., Jung, F., Seifert, B., Klein, f., Weigel, T., Kratz, K., Lendlein, A. %D 2010 %J Journal of Biotechnology %N 1 %P 76-82 %R doi:10.1016/j.jbiotec.2010.01.006 %T Cytocompatibility testings using cell culture modules fabricated from specific candidate biomaterials using injection molding %U https://doi.org/10.1016/j.jbiotec.2010.01.006 1 %X Most polymers used in clinical applications today are materials that have been developed originally for application areas other than biomedicine. Testing the cell- and tissue-compatibility of novel materials in vitro and in vivo is of key importance for the approval of medical devices and is regulated according to the Council Directive 93/42 of the European communities concerning medical devices. In the standardized testing methods the testing sample is placed in commercially available cell culture plates, which are often made from polystyrene. Thus not only the testing sample itself influences cell behavior but also the culture vessel material. In order to exclude this influence, a new system for cell testing will be presented allowing a more precise and systematic investigation by preparing tailored inserts which are made of the testing material. Inserts prepared from polystyrene, polycarbonate and poly(ether imide) were tested for their cytotoxity and cell adherence. Furthermore a proof of principle concerning the preparation of inserts with a membrane-like surface structure and its surface modification was established. Physicochemical investigations revealed a similar morphology and showed to be very similar to the findings to analogous preparations and modifications of flat-sheet membranes. %0 book part %@ %A Wischke, C., Neffe, A., Lendlein, A. %D 2010 %J Advances in Polymer Science - Shape-memory Polymers %P 177-206 %R doi:10.1007/12_2009_29 %T Controlled Drug Release from Biodegradable Shape-Memory Polymers %U https://doi.org/10.1007/12_2009_29 %X of drugs. This chapter provides a detailed description of the molecular basis for such multifunctional SMPs including the selection of building blocks, the polymer morphology, and the three dimensional architecture. Moreover, drug loading and release, drug effects on thermomechanical properties of SMPs, and drug release patterns in a physiological environment are described and potential applications in minimally-invasive surgery are discussed. %0 journal article %@ 0959-9428 %A Scharnagl, N., Lee, S., Hiebl, B., Sisson, A., Lendlein, A. %D 2010 %J Journal of Materials Chemistry %N 40 %P 8789-8802 %R doi:10.1039/C0JM00997K %T Design principles for polymers as substratum for adherent cells %U https://doi.org/10.1039/C0JM00997K 40 %X The next generation of biomaterials for regenerative therapies requires the development of substances, which are able to influence and activate specific phenotype characteristics of cells and tissues. Research towards this aim has resulted in an increasing number of reports about material induced cellular functions and cell-cell interactions. In this context, polymeric materials, which are not intended to degrade can provide helpful in-vitro tools to gain more detailed knowledge about the cell-substrate crosstalk and the resulting cell specific effects. This review aims to consolidate current strategies to induce specific effects on adhesive cells which are related to defined characteristics of two-dimensional systems starting with the molecular dimension, following up with the nanostructure and ending with the surface microstructure. This includes approaches to induce direct or indirect biological responses towards cells by systematic changes in material properties such as hydrophilicity or elasticity. These properties are explained as a function of chemical composition such as the type and ratio of copolymers used for linear polymers, or the geometric arrangement of branching points for network polymer architectures. Surface topographical features are identified to strongly influence cell-substrate interactions and techniques are described to control the surface patterning of polymeric materials on the nano- or microscale. Finally we offer a strategy on how to develop complex and multifunctional materials, which might fulfill the requirements of cell and tissue adapted biomaterials for regenerative therapies. %0 journal article %@ 1582-1838 %A Wang, W., Li, W., Ong, L.-L., Furlani, D., Kaminski, A., Liebold, A., Luetzow, K., Lendlein, A., Wang, J., Li, R.-K., Steinhoff, G., Ma, N. %D 2010 %J Journal of Cellular and Molecular Medicine %N 1-2 %P 392-402 %R doi:10.1111/j.1582-4934.2008.00624.x %T Localized SDF-1alpha gene release mediated by collagen substrate induces CD117+ stem cell homing %U https://doi.org/10.1111/j.1582-4934.2008.00624.x 1-2 %X Results: The optimized parameters for GAC were DNA dosage 10μg/cm2, molar ratio of PEI nitrogen in primary amine to DNA phosphate (N/P ratio) 4 and mass ratio of collagen to DNA (C/D ratio) 1.0. It kept cell viability above 75% and transfection efficiency around 5.8 × 105 RLU/mg protein. GAC allowed the sustained gene release up to 60 days. GAC mediated SDF-1α gene release induced migration and homing of CD117+ stem cells in vitro and in vivo significantly, and the inflammation of GAC reduced significantly two weeks after transplantation. GAC is a promising stem cell based therapeutic strategy for regenerative medicine. %0 journal article %@ 0935-9648 %A Zotzmann, J., Behl, M., Hofmann, D., Lendlein, A. %D 2010 %J Advanced Materials %N 31 %P 3424-3429 %R doi:10.1002/adma.200904202 %T Reversible Triple-Shape Effect of Polymer Networks Containing Polypentadecalactone- and Poly(Epsilon-caprolactone)-Segments %U https://doi.org/10.1002/adma.200904202 31 %X A reversible triple-shape effect is achieved for multi-phase polymer networks based on two different crystallizable segments. The reversibility of the two shape-changes is based on crystallization induced elongation (CIE) occurring during cooling and melting-induced contraction (MIC) during heating under constant stress. %0 book part %@ %A Behl, M., Lendlein, A. %D 2010 %J Shape-Memory Polymers and Multifunctional Composites %P 1-20 %T Overview of Shape-memory Polymers %U %X classes of actively moving materials are introduced with an emphasis on shape-memory polymers. The fundamental principles of the different functions are explained and examples for specific materials are given. %0 conference poster %@ %A Behl, M., Zotzmann, J., Lendlein, A. %D 2010 %J Biodegradable Polymers as Biomaterials, 459th WE-Heraeus-Seminar %T Shape-Memory and Reversible Dual-Shape Effect of Polymer Networks Based on Polypentadecalactone Segments %U %X %0 journal article %@ 0724-8741 %A Wischke, C., Lendlein, A. %D 2010 %J Pharmaceutical Research %N 4 %P 527-529 %R doi:10.1007/s11095-010-0062-5 %T Shape-Memory Polymers as Drug Carriers—A Multifunctional System %U https://doi.org/10.1007/s11095-010-0062-5 4 %X No abstract %0 conference lecture %@ %A Lendlein, A., Kratz, K., Hiebl, B., Behl, M. %D 2010 %J Makromolekulares Kolloquium %T Active Biomaterials %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2010 %J 3. Charite Entrepreneurship Summit 2010 %T The Future of Biomaterials and How to Spot Market Potential Early in Academic Research %U %X %0 conference lecture %@ %A Lendlein, A. %D 2010 %J Intelligente Werkstoffe, BMBF – Expertengespraech %T Aktive Polymersysteme %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2010 %J BIONNALE 2010 %T Polymere fuer die Biomedizin - Das Zusammenspiel von Grundlagenforschung und Anwendungsentwicklung %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2010 %J Institutskolloquium am ITCF Denkendorf %T Polymere fuer die Biomedizin - Das Zusammenspiel von Grundlagenforschung und Anwendungsentwicklung %U %X %0 conference poster %@ %A Wischke, C., Weigel, J., Neffe, A.T., Lendlein, A. %D 2010 %J Biodegradable Polymers as Biomaterials, 459th WE-Heraeus-Seminar %T Understanding instability and rupture of polyalkyl 2-cyanoacrylate capsules %U %X %0 conference poster %@ %A Wischke, C., Neffe, A.T., Lendlein, A. %D 2010 %J GDCh Biannual Meeting of the GDCh-Division Macromolecular Chemistry and Polydays %T Copolyesterdimethacrylate-derived Networks combine Shape-memory, Biodegradability, and Controlled Drug Release %U %X %0 journal article %@ 0928-0987 %A Wischke, C., Neffe, A.T., Steuer, S., Lendlein, A. %D 2010 %J European Journal of Pharmaceutical Sciences %N 11 %P 136-147 %R doi:10.1016/j.ejps.2010.06.003 %T Comparing techniques for drug loading of shape-memory polymer networks–effect on their functionalities %U https://doi.org/10.1016/j.ejps.2010.06.003 11 %X A family of oligo[(var epsilon-caprolactone)-co-glycolide]dimethacrylate (oCG-DMA) derived networks of different glycolide content as well as precursor molecular weight has been synthesized by crosslinking oCG-DMA, providing matrices of different hydrophilicity, network density, and morphology at body temperature. Such networks were loaded with a hydrophilic model drug, ethacridine lactate, either before crosslinking or afterwards by swelling in drug solution. Disadvantageous alterations of the shape-memory functionality and degradation characteristics were observed only in few loaded materials. Loading by swelling generally resulted in low payloads, which slightly increased for more hydrophilic polymer networks, and a substantial burst and fast subsequent release for all investigated materials. Loading before crosslinking gave almost no burst and higher subsequent release rates over longer periods of time. Overall, depending on the needs of a specific application, a material from this polymer family with the desired mechanical properties, shape-memory functionality, and degradation pattern can be selected and combined with drugs when considering that i) loading by swelling is best suited for applications that require high initial doses and ii) loading before crosslinking allows easy variation of payloads and low burst release for therapeutics that are non-sensitive to chemical alterations during crosslinking. %0 conference lecture %@ %A Wischke, C., Neffe, A.T., Lendlein, A. %D 2010 %J Biodegradable Polymers as Biomaterials, 459th WE-Heraeus-Seminar %T Multifunctional polymers combining shape-memory, drug release, and biodegradability %U %X %0 conference poster %@ %A Radke, W., N´Goma, P.Y., Ziegler, H.-J., Zierke, M., Behl, M., Lendlein, A. %D 2010 %J Biodegradable Polymers as Biomaterials, 459th WE-Heraeus-Seminar %T Characterization of Multiblockcopolymers by Chromatographic Techniques %U %X %0 journal article %@ 1386-0291 %A Hiebl, B., Fuhrmann, R., Jung, F., Kratz, K., Lendlein, A., Franke, R.-P. %D 2010 %J Clinical Hemorheology and Microcirculation %N 2-4 %P 117-122 %R doi:10.3233/CH-2010-1289 %T Degradation of and angiogenesis around multiblock copolymers containing poly(Rho-dioxanone)- and poly(Epsilon-caprolactone)-segments subcutaneously implanted in the rat neck %U https://doi.org/10.3233/CH-2010-1289 2-4 %X The degradation behavior and the effect on angiogenesis of multiblock copolymers based on poly(p-dioxanone)- and poly(ε-caprolactone)-segments (PDC) were studied in vivo. PDC is a multifunctional biomaterial combining degradability and shape-memory capabilities. The “in vivo” degradation of PDC is characterized by a fragmentation occurring at the material tissue interface. This observation is consistent with the enzyme supported degradation behaviour, which was determined “in vitro”. PDC revealed to induce the formation of blood micro-vessels nearby in the periimplantary tissues. Both might explain the good PDC integration into tissues in terms of a strong connection between the implant and the periimplantary tissue. Micro blood-vessels might be involved in the clearance of the small particles, which appear in the periimplantary tissue when PDC degrades. %0 journal article %@ 1616-5187 %A Feng, Y., Lu, J., Behl, M., Lendlein, A. %D 2010 %J Macromolecular Bioscience %N 9 %P 1008-1021 %R doi:10.1002/mabi.201000076 %T Progress in Depsipeptide-Based Biomaterials %U https://doi.org/10.1002/mabi.201000076 9 %X Polydepsipeptides – alternating copolymers of an α-amino acid and an α-hydroxy acid – are a group of biodegradable polymers. Versatile polydepsipeptides with or without pendant functional groups, as well as various polymer architectures, for example, providing alternative, random, diblock, triblock, multiblock or graft sequence structures, can be synthesized via ring-opening copolymerization of various morpholine-2,5-dione derivatives. They are potential candidates for a wide range of biomedical applications. Polydepsipeptides are described in this review from the aspect of materials science, especially as biomaterials. We mainly focus on various techniques developed to synthesize polydepsipeptides and their copolymers, biodegradation behaviors, shape-memory properties and possible biomedical applications. %0 editorial %@ 1616-5187 %A Lendlein, A. %D 2010 %J Macromolecular Bioscience %N 9 %P 993-997 %R doi:10.1002/mabi.201000300 %T Editorial: Polymers in Biomedicine %U https://doi.org/10.1002/mabi.201000300 9 %X No abstract %0 journal article %@ 1386-0291 %A Hiebl, B., Mrowietz, C., Goers, J., Bahramsoltani, M., Plendl, J., Kratz, K., Lendlein, A., Jung, F. %D 2010 %J Clinical Hemorheology and Microcirculation %N 2-3 %P 233-238 %R doi:10.3233/CH-2010-1350 %T In vivo evaluation of the angiogenic effects of the multiblock copolymer PDC using the hen's egg chorioallantoic membrane test %U https://doi.org/10.3233/CH-2010-1350 2-3 %X Multiblock copolymers with shape-memory capability attracted tremendous interest as promising candidate materials for smart, degradable implants. In the present study the hen's egg-chorioallantoic membrane test (HET-CAM test) was used to investigate the angiogenic properties of a thermoplastic, biodegradable multiblock copolymer PDC composed of poly(p-dioxanone) hard segments (PPDO) and crystallizable poly(ε-caprolactone) switching segments (PCL), whereby PPDO and PCL homopolymers were investigated as controls. According to our HET-CAM test data, only PDC induced significant microvessel attraction and formation in the contact area of the test specimen after 48hours of incubation showing newly formed blood vessels along the outer edge of the material. In contrast, no newly formed blood vessels were observed around the PPDO or PCL specimen after the same incubation period. These in vivo results indicate that the multiblock copolymer PDC possibly possesses an angiogenic effect and it can induce blood vessel formation in its direct vicinity when it is implanted in vivo. %0 conference lecture %@ %A Lendlein, A. %D 2010 %J 4th Congress on Regenerative Biology and Medicine, BioStar 2010 %T Biomaterials for Regenerative Medicine %U %X %0 conference lecture %@ %A Lendlein, A. %D 2010 %J GTAI Fall Seminar %T Multifunctional Biomaterials %U %X %0 conference lecture %@ %A Lendlein, A. %D 2010 %J Technology and Medicine, Prozess Schluesseltechnologie %T Biomaterial Science @ HZG %U %X %0 conference lecture %@ %A Lendlein, A. %D 2010 %J Biomedical Technology, MEDICA 2010 %T Polymers for Biomedicine %U %X %0 conference lecture %@ %A Lendlein, A. %D 2010 %J Vortrag beim M.I.T. Technology and Licensing Office %T Commercialization of Shape-Memory Polymers %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2010 %J 4. Wiener Biomaterialsymposium %T (Multi)funktionale Polymere und deren Anwendungspotenzial in der Regenerativen Medizin %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2010 %J Anwenderforum Medizintechnik, Medica 2010 %T Polymere fuer die Biomedizin – Ueber das Zusammenspiel von Grundlagenforschung und Anwendungsentwicklung %U %X %0 journal article %@ 1616-5187 %A Wischke, C., Neffe, A.T., Steuer, S., Engelhardt, E., Lendlein, A. %D 2010 %J Macromolecular Bioscience %N 9 %P 1063-1072 %R doi:10.1002/mabi.201000089 %T AB-polymer Networks with Cooligoester and Poly(Eta-butyl acrylate) Segments as a Multifunctional Matrix for Controlled Drug Release %U https://doi.org/10.1002/mabi.201000089 9 %X Semi-crystalline AB-copolymer networks from oligo[(ε-caprolactone)-co-glycolide]dimethacrylates and n-butylacrylate have recently been shown to exhibit a shape-memory functionality, which may be used for self-deploying and anchoring of implants. In this study, a family of such materials differing in their molar glycolide contents χG was investigated to determine structure–property functional relationships of unloaded and drug loaded specimens. Drug loading and release were evaluated, as well as their degradation behavior in vitro and in vivo. Higher χG resulted in higher loading levels by swelling and a faster release of ethacridine lactate, lower melting temperature of polymer crystallites, and a decrease in shape fixity ratio of the programmed temporary shape. For unloaded networks, the material behavior in vivo was independent of the mechanical load associated with different implantation sites and agreed well with data from in vitro degradation studies. Thus, AB networks could be used as novel matrices for biofunctional implants, e.g., for urogenital applications, which can self-anchor in vivo and provide mechanical support, release drugs, and finally degrade in the body to excretable fragments. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2010 %J Annual Meeting of the Dutch Society for Biomaterials and Tissue Engineering %T Designing Multifunctional Polymers and Exploring their Application Potential in Regenerative Therapies %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2010 %J 8. NanoVision %T Formgedaechtnis-Polymere %U %X %0 journal article %@ 1617-9439 %A Neffe, A.T., Lendlein, A. %D 2010 %J Physik-Journal %N 10 %P 56 %T Abbaubare Polymere als Biomaterialien %U 10 %X No abstract %0 book part %@ %A Kratz, K., Wagermaier, W., Heuchel, M., Lendlein, A. %D 2010 %J Shape-Memory Polymers and Multifunctional Composites %P 91-107 %T Thermomechanical Characterizations of Shape-Memory Polymers (Dual/Triple-Shape) and Modeling Approaches %U %X In each chapter, industry experts discuss different key aspects of novel smart materials, from their properties and fabrication to the actuation approaches used to trigger shape recovery. This comprehensive analysis explores the different functions of SMPs, the fundamentals behind them, and the ways in which polymers may reshape product design in general. %0 journal article %@ 1386-0291 %A Mayer, A., Lee, S., Jung, F., Gruetz, G., Lendlein, A., Hiebl, B. %D 2010 %J Clinical Hemorheology and Microcirculation %N 2-3 %P 217-223 %R doi:10.3233/CH-2010-1348 %T CD14+ CD163+ IL-10+ monocytes/macrophages: Pro-angiogenic and non pro-inflammatory isolation, enrichment and long-term secretion profile %U https://doi.org/10.3233/CH-2010-1348 2-3 %X The establishment of a stable endothelial layer on a biomaterial suture is a well known strategy to achieve hemocompatibility. The endothelialisation is supported by factors as e.g. vascular endothelial growth factor (VEGF), which can be secreted by monocytes/macrophages (mo/mΦ) in an angiogenic milieu. In order to avoid detrimental inflammation triggered by these mo/mΦ, we established a protocol for the generation of alternatively activated macrophages and studied their response towards VEGF-A165. We could generate sufficient amounts of these CD14+ CD163+ IL-10+ mo/mΦ from buffy coats(8.6 ± 4.7 × 105 cells/mlbuffy coat). Furthermore, we achieved a VEGF-A165 secretion in the nanogram range. The VEGF-A165 secretion increased 2.1-fold within 14 days from 7.6 ± 2.2 to 16.1 ± 2.5ng/ml when the cells were grown with a VEGF-A165 supplemented (10ng/ml) cell culture medium. Within this time period the secretion levels of other pro-angiogenic growth factors (bFGF, PDGF-BB) and immunomodulatory cytokines (IL-10, IL-12, IL-1ra, TNFα, IFNγ) reached only the picogram range. These results suggest that angiogenically stimulated CD14+ CD163+ IL-10+ mo/mΦ might be useful as a cellular cytokine delivery system supporting endothelialisation of biomaterials without inducing pro-inflammatory effects. %0 journal article %@ 1386-0291 %A Braune, S., Lange, M., Richau, K., Luetzow, K., Weigel, T., Jung, F., Lendlein, A. %D 2010 %J Clinical Hemorheology and Microcirculation %N 2-3 %P 239-250 %R doi:10.3233/CH-2010-1351 %T Interaction of thrombocytes with poly(ether imide): The influence of processing %U https://doi.org/10.3233/CH-2010-1351 2-3 %X The processing of polymers for blood contacting devices can have a major influence on surface properties. In this study, we fabricated poly(ether imide) (PEI) membranes and films to investigate the effects of the processing on physicochemical surface properties by atomic force microscopy (AFM), scanning electron microscopy, contact angle as well as zeta potential measurements. A static platelet adhesion test was performed to analyze the thrombogenicity of both devices. While contact angle measurements showed similar levels of hydrophobicity and zeta potential values were equivalent, mean surface roughness as well as surface energies in the dispersive part were found to be increased for the PEI membrane. The static platelet adhesion test showed a significantly decreased number of adherent platelets per surface area on the PEI film (178.98 ± 102.70/45000 μm2) compared to the PEI membrane (504 ± 314.27/45000μm2) and, consequently, revealed evidence for higher thrombogenicity of the PEI membrane. This study shows that processing can have a significant effect on platelet adhesion to biomaterials, even though, molar weight was identical. Thrombogenicity of polymer-based cardiovascular devices, therefore, have to be evaluated at the final product level, following the entire processing procedure. %0 conference poster %@ %A Zaupa, A., Neffe, A.T., Pierce, B.F., Hofmann, D., Lendlein, A. %D 2010 %J Polymers in Biomedicine and Electronics %T Knowledge-Based Approach to Tailorable Gelatin-Based Materials Functionalized with Tyrosine-Derived Moieties %U %X %0 journal article %@ 1439-9598 %A Scharnagl, N., Lendlein, A., Haag, R., Oenbrink, G. %D 2010 %J Nachrichten aus der Chemie %N 12 %P 1307-1308 %T Polymers in Biomedicine and Electronics %U 12 %X No abstract %0 conference poster %@ %A Kommareddy, K.P., Lange, C., Cui, J., Boergermann, J.H., Manjubala, I., Rumpler, M., Dunlop, J.W.C., Kratz, K., Lendlein, A., Knaus, P., Fratzl, P. %D 2010 %J 4th Congress on Regenerative Biology and Medicine, BioStar 2010 %T Three-dimensional tissue growth in polymer scaffolds with different stiffness and in-vitro influence of BMP-2 on tissue formation in hydroxyapatite scaffolds %U %X %0 conference poster %@ %A Cui, J., Kratz, K., Hiebl, B., Jung, F., Lendlein, A. %D 2010 %J 4th Congress on Regenerative Biology and Medicine, BioStar 2010 %T Poly(n-butyl acrylate) networks with tailored mechanical properties designed as model substrates for mechano-responsive cells %U %X %0 conference poster %@ %A Piluso, S., Lendlein, A., Neffe, A.T. %D 2010 %J Biodegradable Polymers as Biomaterials, 459th WE-Heraeus-Seminar %T Hyaluronic acid-based hydrogels crosslinked by copper-catalyzed azide-alkyne cycloaddition with tailorable mechanical properties %U %X %0 journal article %@ 1313-2458 %A Hiebl, B., Kratz, K., Fuhrmann, R., Jung, F., Lendlein, A., Franke, R.-P. %D 2010 %J Series on BIOMECHANICS %N 3-4 %P 61-65 %T Changes in the subcutaneous tissue and the chorioallantois membrane of eggs caused by poly(p-dioxanone)- and poly(ε- caprolactone) multiblock copolymers %U 3-4 %X %0 conference poster %@ %A Lu, J., Feng, Y., Behl, M., Lendlein, A. %D 2010 %J Biodegradable Polymers as Biomaterials, 459th WE-Heraeus-Seminar %T Biodegradable Depsipeptide-based Biomaterials %U %X %0 conference lecture (invited) %@ %A Behl, M., Feng, Y., Zotzmann, J., Lendlein, A. %D 2010 %J Trilateral Symposium on NanoBio Integration %T Degradable Shape-memory Polymers %U %X %0 conference lecture %@ %A Wischke, C., Krueger, A., Roch, T., Pierce, B.F., Li, W., Jung, F., Lendlein, A. %D 2010 %J 8th International Conference and Workshop on Biological Barriers - In vitro Tools in Nanotoxicology and Nanomedicine %T Endothelial cell response to (co)polymer nanoparticles depending on the inflammatory environment and comonomer ratio %U %X %0 book part %@ %A Wagermaier, W., Kratz, W., Heuchel, M., Lendlein, A. %D 2010 %J Advances in Polymer Science - Shape-memory Polymers %P 97-145 %R doi:10.1007/12_2009_25 %T Characterization Methods for Shape-Memory Polymers %U https://doi.org/10.1007/12_2009_25 %X Finally, as part of a comprehensive characterization, modeling approaches for simulating the thermomechanical behavior of SMPs are presented. At the beginning linear viscoelastic models were applied consisting of coupled spring, dashpot and frictional elements. More recent approaches consider in detail the specific molecular transition underlying the SME, e.g. glass or melting transition. Currently models that incorporate the strain rate dependence and time dependent behavior are under development. %0 journal article %@ 1386-0291 %A Hiebl, B., Bog, S., Mrowietz, C., Juenger, M., Jung, F., Lendlein, A., Franke, R.P. %D 2010 %J Clinical Hemorheology and Microcirculation %N 2-3 %P 211-216 %R doi:10.3233/CH-2010-1347 %T Influence of VEGF stimulated human macrophages on the proliferation of dermal microvascular endothelial cells: Coculture experiments %U https://doi.org/10.3233/CH-2010-1347 2-3 %X Monocytes/macrophages are known to exhibit pro-angiogenic activities after VEGF stimulation. Recently, it was shown that VEGF stimulated macrophages can support growth of microvascular endothelial cells from the lung when both cell types were cocultured using a cell ratio of 1:1. However, endothelial cells can have different phenotypic characteristics and metabolism depending on the originating vascular bed and tissues, and only few data have been published regarding the regiospecific sensitivity of microvascular endothelial cells for angiogenic stimuli. Reports about differences in the microvascular bed of the lung and the skin motivated to investigate angiogenic effects of VEGF stimulated macrophages (mΦa) on the doubling time and the cell growth behaviour of skin derived microvascular endothelial cells (HMVEC/S). During the study period of 60 days, mΦa supported growth and proliferation of the HMVEC/S, when mΦa and HMVEC/S were cocultured at a ratio of 0.5:1. However, these effects were not seen in a 1:1 coculture. This result indicates that there is a positive correlation between the pro-angiogenic effects of mΦa and the number of endothelial cells in the direct neighbourhood of the mΦa and also suggests a different sensitivity of microvascular endothelial cells to angiogenic stimuli depending on the tissue from which they were isolated. %0 conference lecture %@ %A Lendlein, A. %D 2010 %J BCRT Retreat 2010, Biomaterial Workshop %T Multifunctional Biomaterials %U %X %0 journal article %@ 1359-7345 %A Kummerloewe, G., Behl, M., Lendlein, A., Luy, B. %D 2010 %J Chemical Communications : ChemComm %N 43 %P 8273-8275 %R doi:10.1039/C0CC02730H %T Artifact-free measurement of residual dipolar couplings in DMSO by the use of cross-linked perdeuterated poly(acrylonitrile) as alignment medium %U https://doi.org/10.1039/C0CC02730H 43 %X Perdeuterated poly(acrylonitrile) is introduced as a practically proton-free alignment medium for the measurement of anisotropic NMR parameters; its use in conventional glass tubes and in a Kalrez® 8002 UP-based stretching device with resulting spectra of astonishing quality are demonstrated. %0 journal article %@ 0009-286X %A Lendlein, A. %D 2010 %J Chemie - Ingenieur - Technik %N 9 %P 1369 %R doi:10.1002/cite.201050745 %T Aktive Biomaterialien fuer regenerative Therapien %U https://doi.org/10.1002/cite.201050745 9 %X No abstract %0 conference lecture %@ %A Lendlein, A. %D 2010 %J Biomaterialien und Materialien fuer die Energie, GDCh Fachgruppentagung %T Biomaterial Degradation %U %X %0 journal article %@ 1022-1336 %A Neffe, A.T., Zaupa, A., Pierce, B.F., Hofmann, D., Lendlein, A. %D 2010 %J Macromolecular Rapid Communications %N 17 %P 1534-1539 %R doi:10.1002/marc.201000274 %T Knowledge-Based Tailoring of Gelatin-Based Materials by Functionalization with Tyrosine-Derived Groups %U https://doi.org/10.1002/marc.201000274 17 %X Molecular models of gelatin-based materials formed the basis for the knowledge-based design of a physically cross-linked polymer system. The computational models with 25 wt.-% water content were validated by comparison of the calculated structural properties with experimental data and were then used as predictive tools to study chain organization, cross-link formation, and estimation of mechanical properties. The introduced tyrosine-derived side groups, desaminotyrosine (DAT) and desaminotyrosyl tyrosine (DATT), led to the reduction of the residual helical conformation and to the formation of physical net-points by π–π interactions and hydrogen bonds. At 25 wt.-% water content, the simulated and experimentally determined mechanical properties were in the same order of magnitude. The degree of swelling in water decreased with increasing the number of inserted aromatic functions, while Young's modulus, elongation at break, and maximum tensile strength increased. %0 conference lecture %@ %A Lendlein, A. %D 2010 %J Biodegradable Polymers as Biomaterials, 459th WE-Heraeus-Seminar %T Designing Degradable Polymer Networks with Tailored Properties and Functions %U %X %0 conference lecture %@ %A Lendlein, A. %D 2010 %J Lange Nacht der Wissenschaften, Freie Universitaet Berlin %T Polymere in der Medizin %U %X %0 conference lecture %@ %A Lendlein, A. %D 2010 %J Tag der Chemie, Freie Universitaet Berlin %T Neue Chemische Netzwerke in Berlin und Brandenburg %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2010 %J German-Korean Workshop Regenerative Medicine %T Creating and Combining Functions in Polymeric Biomaterials %U %X %0 conference lecture %@ %A Lendlein, A. %D 2010 %J Wissenschaftliches Symposium fuer Prof. Dr. Guenter von Sengbusch, Zentrum fuer Biomaterialentwicklung %T Polymer-based Scaffolds %U %X %0 conference lecture %@ %A Lendlein, A. %D 2010 %J Institutspraesentation zum Besuch von Frau Muench %T Welcome to the Campus Teltow of the GKSS Research Center Centre for Biomaterial Development %U %X %0 journal article %@ 1616-301X %A Zotzmann, J., Behl, M., Feng, Y., Lendlein, A. %D 2010 %J Advanced Functional Materials %N 20 %P 3583-3594 %R doi:10.1002/adfm.201000478 %T Copolymer Networks Based on Poly(Omega-pentadecalactone) and Poly(Epsilon-caprolactone)Segments as a Versatile Triple-Shape Polymer System %U https://doi.org/10.1002/adfm.201000478 20 %X Thermo-sensitive triple-shape polymers can perform two consecutive shape changes in response to heat. These shape changes correspond to the recovery of two different deformations in reverse order, which were programmed previously at elevated temperature levels (Tmid and Thigh) by the application of external stress. Recently, an AB copolymer network was described, which surprisingly exhibited a triple-shape effect despite being programmed with only one deformation at Thigh. Here it is explored whether a copolymer network system can be designed that enables a one-step deformation process at ambient temperature (cold drawing) as a novel, gentle, and easy-to-handle triple-shape-creation procedure, in addition to the procedures reported to date, which generally involve deformation(s) at elevated temperature(s). A copolymer-network system with two crystallizable polyester segments is synthesized and characterized, fulfilling two crucial criteria. These materials can be deformed at ambient temperature by cold drawing and show, even at Thigh, which is above the melting points of both switching domains, elongation at break of up to 250%. Copolymer networks with PCL contents of 75 and 50 wt% show a triple-shape effect after cold drawing with shape-fixity ratios between 65% and 80% and a total-shape-recovery ratio above 97%. Furthermore, in these copolymer networks, the triple-shape effect can be obtained after a one-step deformation at Thigh. Independent of the temperature at which the deformation is applied (ambient temperature or Thigh), copolymer networks that have the same compositions show similar switching temperatures and proportioning of the recovery in two steps. The two-step programming procedure enables a triple-shape effect in copolymer networks for an even broader range of compositions. This versatile triple-shape-material system based on tailored building blocks is an interesting candidate material for applications in fixation systems or disassembling systems. %0 journal article %@ 1662-0356 %A Hofmann, D., Entrialgo, M., Reiche, J., Kratz, K., Lendlein, A. %D 2010 %J Advances in Science and Technology, 5th Forum on new Materials Part E %P 16-24 %R doi:10.4028/www.scientific.net/AST.76.16 %T Molecular Modeling and experimental investigation of hydrolytically degradable polymeric biomaterials %U https://doi.org/10.4028/www.scientific.net/AST.76.16 %X (PLGA)] and copoly(ether)esteruretanes as multiblock copolymers. The molecular modeling approach permits to efficiently investigate the influence of micro-structural properties like free volume distribution, cohesive energy density and concentration of polar functional groups on the bulk water uptake as one constituent part of hydrolytic degradation. The Langmuir monolayer investigations on polymer degradation on the other hand yield the dynamics of bond splitting during degradation within hours separately from time consuming diffusion processes, which may take months in bulk samples. %0 journal article %@ 0032-3861 %A Heuchel, M., Cui, J., Kratz, K., Kosmella, H., Lendlein, A. %D 2010 %J Polymer %N 26 %P 6212-6218 %R doi:10.1016/j.polymer.2010.10.051 %T Relaxation based modeling of tunable shape recovery kinetics observed under isothermal conditions for amorphous shape-memory polymers %U https://doi.org/10.1016/j.polymer.2010.10.051 26 %X The presented modeling approach might be helpful to define design criteria for self sufficiently moving scaffolds within a knowledge-based development process. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2010 %J Bioinspired Systems for Drug, Protein and Gene Delivery, Sino-German Symposium %T Multifunctional Polymers combining Shape-Memory, Drug-Release and Biodegradability %U %X %0 conference lecture %@ %A Behl, M., Lendlein, A. %D 2010 %J German-Thai Symposium on Nanoscience and Nanotechnology %T Biomaterials for Regenerative Medicine %U %X %0 conference lecture (invited) %@ %A Lendlein, A., Behl, M. %D 2010 %J 14th International Scientific Conference on Polymeric Materials %T Actively Moving Polymers %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2010 %J ProcessNet Jahrestagung 2010 %T Aktive Biomaterialien fuer regenerative Therapien %U %X %0 conference lecture %@ %A Lendlein, A. %D 2010 %J Technologieforum, Neue Materialien – Werkstoffe von morgen %T Funktionale Werkstoffsysteme in der Gesundheitswirtschaft %U %X %0 conference lecture %@ %A Lendlein, A. %D 2010 %J Trilaterales Symposium on NanoBio Integration %T Designing (multi)functional polymer networks and exploring their application potential for regenerative therapies %U %X %0 conference paper %@ %A Cui, J., Kratz, K., Lendlein, A. %D 2009 %J Active Polymers - MRS Symposium Proceedings, MRS Spring Meeting 2009 %P NN03-22 %R doi:10.1557/PROC-1190-NN03-22 %T Shape-Memory Properties of Radiopaque Micro-Composites from Amorphous Polyether Urethanes Designed for Medical Application %U https://doi.org/10.1557/PROC-1190-NN03-22 %X %0 conference lecture (invited) %@ %A Behl, M., Ridder, U., Kelch, S., Wagermaier, W., Lendlein, A. %D 2009 %J MRS Spring Meeting 2009 %T Mechanical Properties of Polymer Blends Having Shape-memory Capability %U %X %0 conference lecture (invited) %@ %A Zotzmann, J., Kelch, S., Alteheld, A., Behl, M., Lendlein, A. %D 2009 %J MRS Spring Meeting 2009 %T Ability to Control the Glass Transition Temperature of Amorphous Shape-Memory Polyesterurethane Networks by Varying Prepolymers in Molecular Mass as well as in Type and Content of Incorporated Comonomers %U %X %0 conference lecture %@ %A Luetzow, K., Neffe, A., Lendlein, A. %D 2009 %J Materials Processes for Medical Devices Conference, MPMD 2009 %T Developing Cell Selectivities of Acrylonitrile Based Copolymers and Porous Bodies from Poly(ether imide) %U %X %0 conference lecture (invited) %@ %A Lendlein, A., Behl, M. %D 2009 %J Materials Processes for Medical Devices Conference, MPMD 2009 %T Active Biomaterials %U %X %0 conference lecture %@ %A Kumar, U.N., Kratz, K., Behl, M., Lendlein, A. %D 2009 %J MRS Spring Meeting 2009 %T Triple-Shape Capability of Thermo-Sensitive Nanocomposites from Multiphase Polymer Networks and Magnetic Nanoparticles %U %X %0 conference paper %@ %A Kumar, U.N., Kratz, K., Behl, M., Lendlein, A. %D 2009 %J Active Polymers - MRS Symposium Proceedings, MRS Spring Meeting 2009 %P NN03-21 %R doi:10.1557/PROC-1190-NN03-21 %T Triple-Shape Capability of Thermo-Sensitive Nanocomposites from Multiphase Polymer Networks and Magnetic Nanoparticles %U https://doi.org/10.1557/PROC-1190-NN03-21 %X %0 conference lecture %@ %A Cui, J., Kratz, K., Lendlein, A. %D 2009 %J MRS Spring Meeting 2009 %T Shape-Memory Properties of Radiopaque Micro-Composites from Amorphous Polyether Urethanes Designed for Medical Application %U %X %0 journal article %@ 0391-3988 %A Wang, W., Li, W., Ong, L.-L., Luetzow, K., Lendlein, A., Furlani, D., Gabel, R., Wang, J., Li, R.-K., Steinhoff, G., Ma, N. %D 2009 %J The International Journal of Artificial Organs %N 3 %P 141-149 %T Localized and sustained SDF-1 gene release mediated by fibronectin films: A potential method for recruiting stem cells %U 3 %X to induce targetable stem cell homing. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2009 %J Vortrag am Schulze Diabetes Institut %T Active Biomaterials %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2009 %J International Congress Nanotechnology in Medicine and Biology %T Nanostructured Polymer-based Shape-Memory Materials %U %X %0 conference paper %@ %A Razzaq, M.Y., Behl, M., Kratz, K., Lendlein, A. %D 2009 %J Advances in Material Design for Regenerative Medicine, Drug Delivery, and Targeting/Imaging, MRS Symposium Proceedings, MRS Fall Meeting 2008 %P HH05-07 %R doi:10.1557/PROC-1140-HH05-07 %T Controlled Actuation of Shape-Memory nanocomposites by Application of an Alternating Magnetic Field %U https://doi.org/10.1557/PROC-1140-HH05-07 %X %0 journal article %@ 0168-3659 %A Wischke, C., Neffe, A., Steuer, S., Lendlein, A. %D 2009 %J Journal of Controlled Release %N 3 %P 243-250 %R doi:10.1016/j.jconrel.2009.05.027 %T Evaluation of a degradable shape-memory polymer network as matrix for controlleddrug release %U https://doi.org/10.1016/j.jconrel.2009.05.027 3 %X functionalities, i.e., a shape-memory effect combined with biodegradability and controlled drug release. %0 journal article %@ 0391-3988 %A Wang, W., Li, W., Ong, L.-L., Furlani, D., Gabel, R., Ugurlucan, M., Klopsch, C., Lorenz, P., Luetzow, K., Lendlein, A., Ma, N., Steinhoff, G. %D 2009 %J The International Journal of Artificial Organs %N 7 %P 606 %T Collagen and Fibronectin Substrates Mediated Local SDF-1 Gene Expression Induces Stem Cells Homing %U 7 %X Conclusion: Collagen and fibronectin GASs can induce localized stem cells migration and homing and could be employed to guide tissue formation. %0 conference lecture %@ %A Hofmann, D., Entrialgo-Castano, M., Lendlein, A. %D 2009 %J 2009 Accelrys European User Group Meeting %T Atomistic molecular modelling of hydrolytic degradation utilizing Materials Studio %U %X %0 conference lecture %@ %A Wischke, C., Neffe, A., Steuer, S., Lendlein, A. %D 2009 %J MRS Spring Meeting 2009 %T Amorphous Polymer Networks Combining Three Functionalities - Shape-Memory, Biodegradability, and Drug Release %U %X %0 conference paper %@ %A Wischke, C., Neffe, A., Steuer, S., Lendlein, A. %D 2009 %J Active Polymers - MRS Symposium Proceedings, MRS Spring Meeting 2009 %P NN11-34 %R doi:10.1557/PROC-1190-NN11-34 %T Amorphous Polymer Networks Combining Three Functionalities - Shape-Memory, Biodegradability, and Drug Release %U https://doi.org/10.1557/PROC-1190-NN11-34 %X %0 conference poster %@ %A Wischke, C., Neffe, A., Steuer, S., Lendlein, A. %D 2009 %J Controlled Release Society Annual Meeting & Exposition 2009 %T Amorphous polymer networks combining three functionalities – Shape-memory, biodegradability, and drug release %U %X %0 conference paper %@ %A Hiebl, B., Rickert, D., Fuhrmann, R., Jung, F., Lendlein, A., Franke, R.-P. %D 2009 %J Advances in Material Design for Regenerative Medicine, Drug Delivery, and Targeting/Imaging, MRS Symposium Proceedings, MRS Fall Meeting 2008 %P HH10-04 %R doi:10.1557/PROC-1140-HH10-04 %T Tissue Integration of Two Different Shape-Memory Polymers with Poly(e-Caprolactone) Switching Segment in Rats %U https://doi.org/10.1557/PROC-1140-HH10-04 %X %0 journal article %@ 0935-9648 %A Hofmann, D., Entrialgo-Castano, M., Kratz, K., Lendlein, A. %D 2009 %J Advanced Materials %N 32-33 %P 3237-3245 %R doi:10.1002/adma.200802213 %T Knowledge-Based Approach towards Hydrolytic Degradation of Polymer-Based Biomaterials %U https://doi.org/10.1002/adma.200802213 32-33 %X The concept of hydrolytically degradable biomaterials was developed to enable the design of temporary implants that substitute or fulfill a certain function as long as required to support (wound) healing processes or to control the release of drugs. Examples are surgical implants, e.g., sutures, or implantable drug depots for treatment of cancer. In both cases degradability can help to avoid a second surgical procedure for explanation. Although degradable surgical sutures are established in the clinical practice for more than 30 years, still more than 40% of surgical sutures applied in clinics today are nondegradable.[1] A major limitation of the established degradable suture materials is the fact that their degradation behavior cannot reliably be predicted by applying existing experimental methodologies. Similar concerns also apply to other degradable implants. Therefore, a knowledge-based approach is clearly needed to overcome the described problems and to enable the tailored design of biodegradable polymer materials. In this Progress Report we describe two methods (as examples for tools for this fundamental approach): molecular modeling combining atomistic bulk interface models with quantum chemical studies and experimental investigations of macromolecule degradation in monolayers on Langmuir-Blodgett (LB) troughs. Finally, an outlook on related future research strategies is provided. %0 conference paper %@ %A Kratz, K., Voigt, U., Wagermaier, W., Lendlein, A. %D 2009 %J Advances in Material Design for Regenerative Medicine, Drug Delivery, and Targeting/Imaging, MRS Symposium Proceedings, MRS Fall Meeting 2008 %P HH03-01 %R doi:10.1557/PROC-1140-HH03-01 %T Shape-memory Properties of Multiblock Copolymers Consisting of Poly(?-pentadecalactone) Hard Segments and Crystallisable Poly(e-caprolactone) Switching Segments %U https://doi.org/10.1557/PROC-1140-HH03-01 %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2009 %J 4th World Congress on Regenerative Medicine %T Active Biomaterials for Regenerative Medicine %U %X %0 conference paper %@ %A Kelch, S., Behl, M., Kamlage, S., Lendlein, A. %D 2009 %J Active Polymers - MRS Symposium Proceedings, MRS Spring Meeting 2009 %P NN01-06 %T Multiphase Polymer Networks with Shape-Memory %U %X %0 journal article %@ 0964-1726 %A Weigel, T., Mohr, R., Lendlein, A. %D 2009 %J Smart Materials and Structures %N 2 %P 025011 %R doi:10.1088/0964-1726/18/2/025011 %T Investigation of parameters to achieve temperatures required to initiate the shape-memory effect of magnetic nanocomposites by inductive heating %U https://doi.org/10.1088/0964-1726/18/2/025011 2 %X The activation of the shape-memory effect of nanocomposites (NC) by alternating magnetic fields requires exceeding the switching temperature Ts. Different factors, which can influence this process, have been investigated. The intrinsic properties of magnetic nanoparticles (MNP), their content and distribution in the polymer matrix as well as the heat transport conditions, which are essentially determined by the surface to volume ratio (S/V) of the specimens and their surroundings, influence the achievable temperature in an alternating magnetic field. We used MNP having an iron (II, III) oxide core embedded in amorphous silica, which was homogeneously distributed in a polymer matrix by extrusion moulding. The thermoplastic polymer matrix consists either of an aliphatic polyetherurethane (TFX) for demonstration of the basic correlations between magnetic field and the sample, or of a biodegradable multiblock copolymer (PDC), which is prepared from hard segment forming poly(p-dioxanone)diol (PPDO), switching segment forming poly(ε-caprolactone)diol (PCL) and 2,2(4),4-trimethylhexanediisocyanate (TMDI) as a junction unit. We could demonstrate that a nanoparticle content up to 10 wt% does not decisively change the shape-memory properties or mechanical properties of PDC-based materials. %0 conference lecture %@ %A Wischke, C., Neffe, A., Steuer, S., Lendlein, A. %D 2009 %J 36th Annual Meeting and Exposition of the Controlled Release Society %T Amorphous Polymer Network combining Three Functionalities – Shape-memory, Biodegradability, and Drug Release %U %X %0 journal article %@ 1525-7797 %A Lendlein, A., Zotzmann, J., Feng, Y., Alteheld, A., Kelch, S. %D 2009 %J Biomacromolecules %N 4 %P 975-982 %R doi:10.1021/bm900038e %T Controlling the Switching Temperature of Biodegradable, Amorphous, Shape-Memory Poly(rac-lactide)urethane Networks by Incorporation of Different Comonomers %U https://doi.org/10.1021/bm900038e 4 %X Biodegradable shape-memory polymers have attracted tremendous interest as potential implant materials for minimally invasive surgery. Here, the precise control of the material’s functions, for example, the switching temperature Tsw, is a particular challenge. Tsw should be either between room and body temperature for automatically inducing the shape change upon implantation or slightly above body temperature for on demand activation. We explored whether Tsw of amorphous polymer networks from star-shaped rac-dilactide-based macrotetrols and a diisocyanate can be controlled systematically by incorporation of p-dioxanone, diglycolide, or ε-caprolactone as comonomer. Thermomechanical experiments resulted that Tsw could be adjusted between 14 and 56 °C by selection of comonomer type and ratio without affecting the advantageous elastic properties of the polymer networks. Furthermore, the hydrolytic degradation rate could be varied in a wide range by the content of easily hydrolyzable ester bonds, the material’s hydrophilicity, and its molecular mobility. %0 journal article %@ 0022-2860 %A Pimthon, J., Willumeit, R., Lendlein, A., Hofmann, D. %D 2009 %J Journal of Molecular Structure %N 1-3 %P 38-50 %R doi:10.1016/j.molstruc.2008.12.025 %T All-atom molecular dynamics simulation studies of fully hydrated gel phase DPPG and DPPE bilayers %U https://doi.org/10.1016/j.molstruc.2008.12.025 1-3 %X Here in silico lipid membranes are described providing a structural background of the organization of the lipid components of membranes and aiding further biological or biophysical studies. An all-atom molecular dynamics simulations has been performed to investigate structural and dynamical properties of two fully hydrated gel-phase bilayers of 1,2-dipalmitoyl-sn-glycero-3-phosphoglycerol (DPPG) and 1,2-dipalmitoyl-sn-glycero-3-phospho-ethanolamine (DPPE) bilayers at 303 K. The respective starting configuration of lipids in the simulation bilayer unit cells were taken on the basis of scattering data. In both simulations, we found overall reasonably good agreement with the available experimental data (area per lipid, phosphorus–phosphorus distance). The distribution of the water/counterions at the membrane interface, interactions/orientations of lipid headgroups, and hydrocarbon chain organization were extensively studied in terms of pair distribution functions between main structural components of the system. Intra/intermolecular hydrogen bond formation was discussed in detail. The water orientation at the lipid membrane interface was explored thoroughly in terms of dipole moment as a function of the water molecule positions along the membrane, where we found that the counterions changed the orientation of the water at the interface. Special attention has been devoted to the distribution of the sodium counterions around the DPPG headgroup. We found preferential binding of Na+ ions to the phosphate oxygen species. %0 journal article %@ 1616-5187 %A Feng, Y., Behl, M., Kelch, S., Lendlein, A. %D 2009 %J Macromolecular Bioscience %N 1 %P 45-54 %R doi:10.1002/mabi.200800199 %T Biodegradable Multiblock Copolymers Based on Oligodepsipeptides with Shape-Memory Properties %U https://doi.org/10.1002/mabi.200800199 1 %X Thermoplastic phase-segregated multiblock copolymers with polydepsipeptides and PCL segments were prepared via coupling of diol and PCL-diol using an aliphatic diisocyanate. The obtained multiblock copolymers showed good elastic properties and a shape memory. Almost complete fixation of the mechanical deformation, resulting in quantitative recovery of the permanent shape with a switching temperature around body temperature, was observed. In hydrolytic degradation experiments, a quick decrease of the molecular weight without induction period was observed, and the material changed from elastic to brittle in 21 d. These materials promise a high potential for biomedical applications such as smart implants or medical devices. %0 journal article %@ 0920-5063 %A Kostadinova, A., Seifert, B., Albrecht, W., Malsch, G., Groth, T., Lendlein, A., Altankov, G. %D 2009 %J Journal of Biomaterials Science - Polymer Edition %N 5-6 %P 821-839 %R doi:10.1163/156856209X427005 %T Novel Polymer Blends for the Preparation of Membranes for Biohybrid Liver Systems %U https://doi.org/10.1163/156856209X427005 5-6 %X It was found previously that membranes based on co-polymers of acrylonitrile (AN) and 2-acrylamido-2-methyl-propansulfonic acid (AMPS) greatly stimulated the functionality and survival of primary hepatocytes. In those studies, however, the pure AN-AMPS co-polymer had poor membrane-forming properties, resulting in quite dense rubber-like membranes. Hence, membranes with required permeability and optimal biocompatibility were obtained by blending the AN-AMPS co-polymer with poly(acrylonitrile) homopolymer (PAN). The amount of PAN (P) and AN-AMPS (A) in the blend was varied from pure PAN (P/A-100/0) over P/A-75/25 and P/A-50/50 to pure AN-AMPS co-polymer (P/A-0/100). A gradual decrease of molecular cut-off of membranes with increase of AMPS concentration was found, which allows tailoring membrane permeability as necessary. C3A hepatoblastoma cells were applied as a widely accepted cellular model for assessment of hepatocyte behaviour by attachment, viability, growth and metabolic activity. It was found that the blend P/A-50/50, which possessed an optimal permeability for biohybrid liver systems, supported also the attachment, growth and function of C3A cells in terms of fibronectin synthesis and P-450 isoenzyme activity. Hence, blend membranes based on a one to one mixture of PAN and AN-AMPS combine sufficient permeability with the desired cellular compatibility for application in bioreactors for liver replacement. %0 journal article %@ 1744-683X %A Behl, M., Ridder, U., Feng, Y., Kelch, S., Lendlein, A. %D 2009 %J Soft Matter %N 3 %P 676-684 %R doi:10.1039/b810583a %T Shape-memory capability of binary multiblock copolymer blends with hard and switching domains provided by different components %U https://doi.org/10.1039/b810583a 3 %X The structural concept of shape-memory polymers (SMP) is based on two key components: covalent or physical crosslinks (hard domains) determining the permanent shape and switching domains fixing the temporary shape as well as determining the switching temperature Tsw. In conventional thermoplastic SMP hard and switching domains determining segments are combined in one macromolecule. In this paper we report on binary polymer blends from two different multiblock copolymers, whereby the first one provides the segments forming hard domains and the second one the segments forming the switching domains. A poly(alkylene adipate) mediator segment is incorporated in both multiblock copolymers to promote their miscibility as the hard segment poly(p-dioxanone) (PPDO) and the switching segment poly(-caprolactone) (PCL) are non-miscible. All polymer blends investigated showed excellent shape-memory properties. The melting point associated to the PCL switching domains Tm,PCL is almost independent of the weight ratio of the two blend components. At the same time the mechanical properties can be varied systematically. In this way complex synthesis of new materials can be avoided. Its biodegradability, the variability of mechanical properties and a Tsw around body temperature are making this binary blend system an economically efficient, suitable candidate for diverse biomedical applications. %0 conference paper %@ %A Hofmann, D., Pimthon, J., Willumeit, R., Lendlein, A. %D 2009 %J Advances in Material Design for Regenerative Medicine, Drug Delivery, and Targeting/Imaging, MRS Symposium Proceedings, MRS Fall Meeting 2008 %P HH09-07 %R doi:10.1557/PROC-1140-HH09-07 %T Computational modeling of anionic and zwitterionic lipid bilayers for investigating surface activities of bioactive molecules %U https://doi.org/10.1557/PROC-1140-HH09-07 %X %0 lecture %@ %A Lendlein, A. %D 2009 %J %T Shape-memory Polymers %U %X %0 conference lecture %@ %A Neffe, A.T., Steuer, S., Hanh, B.-D., Lendlein, A. %D 2009 %J 4th World Congress on Regenerative Medicine %T Polymer networks combining three functionalities – shape-memory, biodegradability, and drug release %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2009 %J 12th German-American Frontiers of Engineering Symposium %T Shape-Memory Polymers for Biomedical Applications %U %X %0 journal article %@ 0957-4530 %A Zotzmann, J., Alteheld, A., Behl, M., Lendlein, A. %D 2009 %J Journal of Materials Science: Materials in Medicine %N 9 %P 1815-1824 %R doi:10.1007/s10856-009-3761-x %T Amorphous phase-segregated copoly(ether)esterurethane thermoset networks with oligo(propylene glycol) and oligo[(rac-lactide)-co-glycolide] segments: synthesis and characterization %U https://doi.org/10.1007/s10856-009-3761-x 9 %X Completely amorphous copoly(ether)ester networks based on oligo(propylene glycol) and oligo[(rac-dilactide)-co-glycolide] segments were synthesized by crosslinking star-shaped hydroxyl-telechelic cooligomers using an aliphatic low-molecular weight diisocyanate. Two different network architectures were applied exhibiting differences in the phase-separation behavior. For networks from oligo(propylene glycol)-block-oligo[(rac-lactide)-co-glycolide] triols (G3OPG-bl-OLG) only one glass transition was obtained. However, networks from a mixture of oligo(propylene glycol) triols (G3OPG) and oligo[(rac-lactide)-co-glycolide] tetrols (P4OLG) with a ratio of components in a certain range show two glass transition temperatures (T g) being attributed to two segregated amorphous phases. In this way a wide spectrum of mechanical properties can be realized and adjusted to the requirements of a specific application. %0 journal article %@ 1616-301X %A Behl, M., Bellin, I., Kelch, S., Wagermaier, W., Lendlein, A. %D 2009 %J Advanced Functional Materials %N 1 %P 102-108 %R doi:10.1002/adfm.200800850 %T One-Step Process for Creating Triple-Shape Capability of AB Polymer Networks %U https://doi.org/10.1002/adfm.200800850 1 %X Triple-shape polymers can move from a first shape (A) to a second shape (B) and from there to a third shape (C), where both shape changes are induced by temperature increases. This triple-shape capability is obtained for multiphase polymer networks after application of a complex thermomechanical programming process, which consists of two steps; these steps create shapes (B) and (A), while shape (C) is defined by the covalent crosslinks of the polymer network. Here, the creation of the triple-shape capability for an AB polymer network system by a simple one-step process similar to a conventional dual-shape programming process is reported. The polymer networks are based on poly(-caprolactone) (PCL) and poly(cyclohexyl methacrylate); favorable compositions for obtaining a triple shape effect have a PCL content between 35 and 60 wt%. This finding substantially facilitates handling of the triple-shape technology and is an important step toward the realization of potential applications in which more than one shape change is required. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2009 %J Kolloquien der GDCh-Ortsverbaende %T Active Polymers for Biomedical Applications %U %X %0 conference lecture %@ %A Hofmann, D., Entrialgo, M., Pimthon, J., Willumeit, R., Lendlein, A. %D 2009 %J 4th World Congress on Regenerative Medicine 2009 %T Molecular Modelling of Polymer-based Biomaterials and Surface Activities of Bioactive Molecules %U %X %0 journal article %@ 0935-9648 %A Neffe, A.T., Hanh, B.D., Steuer, S., Lendlein, A. %D 2009 %J Advanced Materials %N 32-33 %P 3394-3398 %R doi:10.1002/adma.200802333 %T Polymer Networks Combining Controlled Drug Release, Biodegradation, and Shape Memory Capability %U https://doi.org/10.1002/adma.200802333 32-33 %X No abstract %0 conference lecture %@ %A Lendlein, A. %D 2009 %J Materialwissenschaft und Werkstofftechnik, DFG-Nachwuchsakademie %T Shape-memory Polymers %U %X %0 conference lecture (invited) %@ %A Kelch, S., Behl, M., Kamlage, S., Lendlein, A. %D 2009 %J MRS Spring Meeting 2009 %T Multiphase Polymer Networks with Shape-Memory %U %X %0 conference paper %@ %A Behl, M., Ridder, U., Kelch, S., Wagermaier, W., Lendlein, A. %D 2009 %J Active Polymers - MRS Symposium Proceedings, MRS Spring Meeting 2009 %P NN01-05 %T Mechanical Properties of Polymer Blends Having Shape-memory Capability %U %X %0 conference paper %@ %A Hiebl, B., Kratz, K., Fuhrmann, R., Jung, F., Lendlein, A., Franke, R.-P. %D 2009 %J Active Polymers - MRS Symposium Proceedings, MRS Spring Meeting 2009 %P NN06-05 %R doi:10.1557/PROC-1190-NN06-05 %T In vivo degradation behavior of PDC multiblock copolymers containing poly(para-dioxanone) hard segments and crystallizable poly(epsilon-caprolactone) switching segments %U https://doi.org/10.1557/PROC-1190-NN06-05 %X %0 lecture %@ %A Neffe, A., Lendlein, A. %D 2009 %J %T Shape-Memory Polymers %U %X %0 conference poster %@ %A Braune, S., Lange, M., Luetzow, K., Jung, F., Haag, R., Lendlein, A. %D 2009 %J 28. Jahrestagung der Deutschen Gesellschaft fuer Klinische Mikrozirkulation und Haemorheologie %T Interaction of thrombocytes with poly(ether imide): the influence of processing %U %X %0 conference lecture (invited) %@ %A Lendlein, A., Tronci, G., Zaupa, A., Pierce, B., Neffe, A., Cui, J., Kratz, K. %D 2009 %J Biomechanics and Biology of Bone Healing, International Symposium 2009 %T Biomimetic Scaffolds supporting Bone Regeneration in Critical Defects %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2009 %J Nanomedizin -Nanotechnologien fuer die Gesundheit, Praesentationsveranstaltung des BMBF %T Important Future Research Topics in the Area of Biomaterials and Regenerative Medicine %U %X %0 conference lecture %@ %A Madbouly, S., Kratz, K., Klein, F., Luetzow, K., Lendlein, A. %D 2009 %J MRS Spring Meeting 2009 %T Thermomechanical Behaviour of Biodegradable Shape-memory Polymer Foams %U %X %0 conference paper %@ %A Madbouly, S., Kratz, K., Klein, F., Luetzow, K., Lendlein, A. %D 2009 %J Active Polymers - MRS Symposium Proceedings, MRS Spring Meeting 2009 %P NN04-04 %R doi:10.1557/PROC-1190-NN04-04 %T Thermomechanical Behaviour of Biodegradable Shape-memory Polymer Foams %U https://doi.org/10.1557/PROC-1190-NN04-04 %X %0 conference lecture %@ %A Wagermaier, W., Hofmann, D., Kratz, K., Behl, M., Lendlein, A. %D 2009 %J MRS Spring Meeting 2009 %T X-ray Scattering Studies to Investigate Triple-shape Capability of Polymer Networks Based on poly(?-caprolactone) and poly(cyclohexyl methacrylate) Segments %U %X %0 conference paper %@ %A Wagermaier, W., Hofmann, D., Kratz, K., Behl, M., Lendlein, A. %D 2009 %J Active Polymers - MRS Symposium Proceedings, MRS Spring Meeting 2009 %P NN03-18 %R doi:10.1557/PROC-1190-NN03-18 %T X-ray Scattering Studies to Investigate Triple-shape Capability of Polymer Networks Based on poly(?-caprolactone) and poly(cyclohexyl methacrylate) Segments %U https://doi.org/10.1557/PROC-1190-NN03-18 %X %0 conference poster %@ %A Hiebl, B., Kratz, K., Fuhrmann, R., Jung, F., Lendlein, A., Franke, R.-P. %D 2009 %J MRS Spring Meeting 2009 %T In vivo degradation behavior of PDC multiblock copolymers containing poly(para-dioxanone) hard segments and crystallizable poly(epsilon-caprolactone) switching segments %U %X %0 conference poster %@ %A Tzoneva, R., Seifert, B., Weckwerth, C., Pehlivanova, V., Tsoneva, I., Lendlein, A. %D 2009 %J Biology – Traditions and Challenges, 11th Anniversary Scientific Conference %T Study of endothelial cell adhesion and function on shape - memory polymers for needs of tissue engineering and regenerative medicine %U %X %0 conference lecture %@ %A Hiebl, B., Fuhrmann, R., Jung, F., Kratz, K., Lendlein, A., Franke, R.-P. %D 2009 %J 15th Conference of the European Society of Clinical Hemorheology and Microcirculation %T Degradation of and angiogenesis around multiblock copolymers containing poly(Rho-dioxanone)- and poly(Epsilon-caprolactone)-segments subcutaneously implanted in the rat neck %U %X %0 conference poster %@ %A Kommareddy, K.P., Lange, C., Rumpler, M., Inderchand, M., Cui, J., Kratz, K., Boergermann, J.H., Lendlein, A., Knaus, P., Fratzl, P. %D 2009 %J 36th European Symposium on Calcified Tissues %T Influence on three-dimensional tissue growth by scaffold architecture %U %X %0 journal article %@ 8756-3282 %A Kommareddy, K.P., Lange, C., Rumpler, M., Inderchand, M., Cui, J., Kratz, K., Boergermann, J.H., Lendlein, A., Knaus, P., Fratzl, P. %D 2009 %J Bone %N S 2 %P S261-S262 %R doi:10.1016/j.bone.2009.03.450 %T Influence on three-dimensional tissue growth by scaffold architecture %U https://doi.org/10.1016/j.bone.2009.03.450 S 2 %X No abstract %0 conference paper %@ %A Zotzmann, J., Kelch, S., Alteheld, A., Behl, M., Lendlein, A. %D 2009 %J Active Polymers - MRS Symposium Proceedings, MRS Spring Meeting 2009 %P NN01-09 %R doi:10.1557/PROC-1190-NN01-09 %T Ability to Control the Glass Transition Temperature of Amorphous Shape-Memory Polyesterurethane Networks by Varying Prepolymers in Molecular Mass as well as in Type and Content of Incorporated Comonomers %U https://doi.org/10.1557/PROC-1190-NN01-09 %X %0 conference lecture %@ %A Fratzl, P., Weinkamer, R., Inderchand, M., Roschger, P., Lendlein, A., Duda, G. %D 2009 %J World Congress on Medical Physics and Biomedical Engineering %T Materials Science Aspects of Bone Fracture and Regeneration %U %X %0 conference object %@ %A Fratzl, P., Weinkamer, R., Inderchand, M., Roschger, P., Lendlein, A., Duda, G. %D 2009 %J IFMBE Proceedings, World Congress on Medical Physics and Biomedical Engineering %N 10 %P 259 %R doi:10.1007/978-3-642-03900-3 %T Materials Science Aspects of Bone Fracture and Regeneration %U https://doi.org/10.1007/978-3-642-03900-3 10 %X %0 journal article %@ 1525-0016 %A Wang, W., Li, W.Z., Ong, L., Luetzow, K., Lendlein, A., Furlani, D., Gaebel, R., Kong, D.L., Wang, J., Steinhoff, G., Ma, N. %D 2009 %J Molecular Therapy %N S1 %P S 269 %R doi:10.1016/S1525-0016(16)39061-X %T Fibronectin Films-Mediated SDF-1 Gene Release Recruits Stem Cells %U https://doi.org/10.1016/S1525-0016(16)39061-X S1 %X No abstract %0 conference lecture %@ %A Wang, W., Li, W.Z., Ong, L., Luetzow, K., Lendlein, A., Furlani, D., Gaebel, R., Kong, D.L., Wang, J., Steinhoff, G., Ma, N. %D 2009 %J 12th Annual Meeting of the American Society of Gene Therapy %T Fibronectin Films-Mediated SDF-1 Gene Release Recruits Stem Cells %U %X %0 conference lecture %@ %A Hiebl, B., Fuhrmann, R., Jung, F., Kelch, S., Lendlein, A., Franke, R.-P. %D 2009 %J 28. Jahrestagung der Deustchen Gesellschaft fuer Klinische Mikrozirkulation und Haemorheologie %T Degradation of and angiogenesis around multiblock copolymers based on poly(Rho-dioxanone)/poly(Epsilon-caprolactone) subcutaneously implanted in the rat neck %U %X %0 lecture %@ %A Lendlein, A., Schroeter, M. %D 2009 %J %T Biomaterial Science II %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2009 %J Tierbiochemisches Seminar, Institut fuer Veterinaer-Biochemie %T Polymere fuer biomedizinische Anwendungen %U %X %0 journal article %@ 1525-0016 %A Furlani, D., Li, W.Z., Wang, L., Pittermann, E., Mark, P., Delyagina, E., Luetzow, K., Lendlein, A., Steinhoff, G., Ma, N. %D 2009 %J Molecular Therapy %N S1 %P S 135 %R doi:10.1016/S1525-0016(16)38707-X %T Abnormal Cells Appeared in Early Passage Cultured Mesenchymal Stem Cells Show Aberrant Genotype, Karyotype and Metabolism %U https://doi.org/10.1016/S1525-0016(16)38707-X S1 %X No abstract %0 conference lecture (invited) %@ %A Lendlein, A., Luetzow, K., Hiebl, B., Lange, M., Weigel, T., Seifert, B., Klein, F., Tronci, G., Neffe, A. %D 2009 %J Organotyp Tissue Culture Techniques for Substance Evaluation, DECHEMA/BioTop Potsdam Symposium %T Biomaterials and Scaffolds for Tissue Regeneration %U %X %0 journal article %@ 1075-2617 %A Pimthon, J., Willumeit, R., Lendlein, A., Hofmann, D. %D 2009 %J Journal of Peptide Science %N 10 %P 654-667 %R doi:10.1002/psc.1165 %T Membrane association and selectivity of the antimicrobial peptide NK-2: A molecular dynamics simulation study %U https://doi.org/10.1002/psc.1165 10 %X In an effort to better understand the initial mechanism of selectivity and membrane association of the synthetic antimicrobial peptide NK-2, we have applied molecular dynamics simulation techniques to elucidate the interaction of the peptide with the membrane interfaces. A homogeneous dipalmitoylphosphatidylglycerol (DPPG) and a homogeneous dipalmitoylphosphatidylethanolamine (DPPE) bilayers were taken as model systems for the cytoplasmic bacterial and human erythrocyte membranes, respectively. The results of our simulations on DPPG and DPPE model membranes in the gel phase show that the binding of the peptide, which is considerably stronger for the negatively charged DPPG lipid bilayer than for the zwitterionic DPPE, is mostly governed by electrostatic interactions between negatively charged residues in the membrane and positively charged residues in the peptide. In addition, a characteristic distribution of positively charged residues along the helix facilitates a peptide orientation parallel to the membrane interface. Once the peptides reside close to the membrane surface of DPPG with the more hydrophobic side chains embedded into the membrane interface, the peptide initially disturbs the respective bilayer integrity by a decrease of the order parameter of lipid acyl chain close to the head group region, and by a slightly decrease in bilayer thickness. We found that the peptide retains a high content of helical structure on the zwitterionic membrane-water interface, while the loss of -helicity is observed within a peptide adsorbed onto negatively charged lipid membranes. %0 conference lecture %@ %A Furlani, D., Li, W.Z., Wang, L., Pittermann, E., Mark, P., Delyagina, E., Luetzow, K., Lendlein, A., Steinhoff, G., Ma, N. %D 2009 %J 12th Annual Meeting of the American Society of Gene Therapy %T Abnormal Cells Appeared in Early Passage Cultured Mesenchymal Stem Cells Show Aberrant Genotype, Karyotype and Metabolism %U %X %0 conference paper %@ %A Neffe, A.T., Hanh, B.D., Steuer, S., Wischke, C., Lendlein, A. %D 2009 %J Active Polymers - MRS Symposium Proceedings, MRS Spring Meeting 2009 %P NN06-02 %R doi:10.1557/PROC-1190-NN06-02 %T Thermomechanical Properties and Shape-Memory Capability of Drug Loaded Semi-Crystalline Polyestermethacrylate Networks %U https://doi.org/10.1557/PROC-1190-NN06-02 %X %0 conference lecture %@ %A Lendlein, A. %D 2009 %J Vortrag bei BASF %T Aktive Biomaterialien %U %X %0 lecture %@ %A Lendlein, A. %D 2009 %J %T Multifunctional Biomaterials %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2009 %J 10th International Symposium on Polymers for Advanced Technologies, PAT 2009 %T Shape-memory Polymers for Biomedical Applications %U %X %0 journal article %@ 0935-9648 %A Shastri, V.P., Lendlein, A. %D 2009 %J Advanced Materials %N 32-33 %P 3231-3234 %R doi:10.1002/adma.200902200 %T Materials in Regenerative Medicine %U https://doi.org/10.1002/adma.200902200 32-33 %X No abstract %0 journal article %@ 0023-5563 %A Weigel, T., Ziegler, H.-J., Lendlein, A., Wieser, J., Khare, S. %D 2009 %J Kunststoffe : KU %N 10 %P 32-36 %T Formgedaechtniseffekt in Polymercompounds - Magnetisierbare Nanopartikel %U 10 %X Compounds aus thermoplastischen Polyurethanen mit guten Formgedächtniseigenschaften und magnetisierbaren Nanopartikeln können im elektromagnetischen Wechselfeld sozusagen in Form gebracht werden. Potenzielle Anwendungen eröffnen sich z.B. für Aktuatoren in technischen Prozessen oder als Nahtmaterial im medizinischen Bereich. %0 conference lecture %@ %A Lendlein, A. %D 2009 %J TERMIS-World Congress %T Creating and Combining Functions in Polymeric Biomaterials %U %X %0 conference lecture %@ %A Lendlein, A. %D 2009 %J Institutspraesentation bei der Firma NEPES %T Multifunctional Biomaterials %U %X %0 journal article %@ 1862-4243 %A Weigel, T., Ziegler, H.-J., Lendlein, A., Wieser, J., Khare, S. %D 2009 %J Kunststoffe International %N 10 %P 17-20 %T Shape Memory Effect in Polymer Compounds - Magnetizable Nanoparticles %U 10 %X Compounds based on thermoplastic polyurethanes with good shape memory properties and magnetizable nanoparticles can be induced to return to an original shape by an alternating electromagnetic field. This opens up potential applications such as actuators in technical processes or suture material in the medical sector. %0 conference lecture %@ %A Lee, S., Ganesan, R., Braune, S., Kratz, K., Lendlein, A., Jung, F. %D 2009 %J 28. Jahrestagung der Deutschen Gesellschaft fuer Klinische Mikrozirkulation und Haemorheologie %T Big ET-1 derived peptides enhances endothelial cell shear resistancy %U %X %0 lecture %@ %A Neffe, A.T., Lendlein, A. %D 2009 %J %T Wirkstoffdesign und Freisetzungssysteme %U %X %0 conference poster %@ %A Neffe, A.T., Hanh, B.D., Steuer, S., Wischke, C., Lendlein, A. %D 2009 %J MRS Spring Meeting 2009 %T Thermomechanical Properties and Shape-Memory Capability of Drug Loaded Semi-Crystalline Polyestermethacrylate Networks %U %X %0 lecture %@ %A Neffe, A.T., Lendlein, A. %D 2009 %J %T Introduction to Peptide Synthesis %U %X %0 conference lecture %@ %A Lendlein, A. %D 2009 %J World Health Summit, Symposium an der Charite %T Materials in Regenerative Medicine %U %X %0 conference poster %@ %A Mrowietz, C., Hiebl, B., Goers, J., Bahramsoltani, M., Plendl, J., Kratz, K., Lendlein, A., Jung, F. %D 2009 %J 28. Jahrestagung der Deutschen Gesellschaft fuer Klinische Mikrozirkulation und Haemorheologie %T In vitro testing of angiogenic effects derived from polymer based biomaterials using the Hen’s egg test-chorioallantoic membrane method %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2009 %J Intelligente Werkstoffe, DGM Themenfindungsworkshop %T Aktive Polymersysteme %U %X %0 book part %@ %A Bellin, K., Behl, M., Lendlein, A. %D 2008 %J Aktuelles aus der Klinischen Haemorheologie und Mikrozirkulation %P 15-17 %T Massschneidern von Eigenschaften und Funktionen von Polymeren fuer Anwendungen in der Medizin %U %X %0 conference lecture %@ %A Behl, M., Lendlein, A. %D 2008 %J 3rd International Conference on Nanotechnology and Textiles %T Shape-Memory Polymers %U %X %0 conference lecture %@ %A Lendlein, A. %D 2008 %J 1. Workshop Wundheilung %T Polymer Systems based on Classical (Co-)Monomers %U %X %0 journal article %@ 1549-3296 %A Ren, T., Weigel, T., Groth, T., Lendlein, A. %D 2008 %J Journal of Biomedical Materials Research A %N 1 %P 209-219 %R doi:10.1002/jbm.a.31508 %T Microwave plasma surface modification of silicone elastomer with allylamine for improvement of biocompatibility %U https://doi.org/10.1002/jbm.a.31508 1 %X The microwave plasma surface modification of silicone elastomer with allylamine was studied to improve the biocompatibility of the material. An effort was made to clarify the relationships among plasma conditions and surface chemical composition, physical surface properties and biocompatibility of material, as well as the stability of plasma deposited layers. ATR-IR, XPS, Ellipsometry measurements, and contact angle measurements were used to investigate the changes of surface. The stability of plasma-treated silicone surfaces were also studied. The results demonstrated that the temperature and pressure had a strong influence on the chemical composition and structure of surface-deposited layer. The layer was nearly completely crosslinking when the modification was carried out at 60°C. The polymerization speed decreased linearly with temperature. The XPS analysis results showed that the nitrogen element content in the surface layer was very high, especially under low pressure. The nitrogen/carbon ratio in the layer even greatly surpassed that of the allylamine monomer. The wettability of the silicone surface was greatly improved after plasma modification, and increased with the quantities of amine groups. The plasma-treated surfaces have good storage stability in air up to 3 months. The wettability of the surfaces decreased incipiently and then it dramatically increased with further time. The human skin fibroblasts were used to evaluate biocompatibility of plasma-treated silicone elastomer. The surface biocompatibility was greatly improved after modification; human skin fibroblasts adhered quickly and grew well on the modified silicone surface. %0 journal article %@ 0957-4530 %A Tzoneva, R., Seifert, B., Albrecht, W., Richau, K., Groth, K., Lendlein, A. %D 2008 %J Journal of Materials Science: Materials in Medicine %N 10 %P 3203-3210 %R doi:10.1007/s10856-008-3456-8 %T Hemocompatibility of poly(ether imide) membranes functionalized with carboxylic groups %U https://doi.org/10.1007/s10856-008-3456-8 10 %X Materials for blood-contacting applications have to meet high requirements in terms to prevent thrombotic complications after the medical treatment. Surface induced thrombosis, e.g., after application of cardiovascular devices, is linked clearly to the activation of coagulation system and platelet adhesion and activation. The flat sheet poly(ether imide) membrane (PEI) was modified by binding of iminodiacetic acid (IDA) for different periods of time to obtain surfaces with carboxylic (–COOH) groups, namely PEI-1 (modified for 1 min) and PEI-2 (modified for 30 min). The successful binding of the ligands was monitored by thionin acetate assay. The physico-chemical characteristics of the materials were analyzed by SEM, AFM, water contact angle, and Zeta potential measurements. Hemocompatibility of the polymer materials was studied by analyzing the activation of coagulation system (plasma kallikrein-like activity) and platelet adhesion/activation by using immunofluorescence technique. The blood response to PEI membranes was compared to that of a commercial poly(ethylene terephthalate) (PET) membrane. Our results showed that the increase of the negative charges on the modified PEI membrane surfaces (number of –COOH groups) caused a higher contact activation of the coagulation system and a higher rate of platelet adhesion and activation compared to non-modified PEI. However, overall the hemocompatibility of all PEI membranes was higher than that of PET. %0 conference lecture %@ %A Lendlein, A. %D 2008 %J Wissenschaftliches Kolloquium an der Charite %T Polymersysteme fuer Anwendungen in der Medizin %U %X %0 conference lecture (invited) %@ %A Lendlein, A., Luetzow, K., Madbouly, S., Weigel, T., Reiche, J., Kratz, K., Tronci, G., Neffe, A.T. %D 2008 %J Biomechanics and Biology of Bone Healing, Symposium und Gruendung des Julius Wolff Instituts %T Formation of Foams from Biodegradable Artificial Materials and Biopolymers %U %X %0 conference lecture %@ %A Haag, R., Lendlein, A., Calderon, M., Schroeter, M., Hertel, G., Keller, M. %D 2008 %J Lange Nacht der Wissenschaften %T Vom Funktionsmaterial zu Megabubbles %U %X %0 conference lecture %@ %A Lendlein, A. %D 2008 %J Vortrag an der Freien Universitaet %T (Bio)aktive polymere Materialien %U %X %0 conference lecture %@ %A Lendlein, A. %D 2008 %J Adaptive Implantate, DFG Exzellenzakademie Medizintechnik %T Polymerbasierte Biomaterialien %U %X %0 journal article %@ 0920-5063 %A Tzoneva, R., Seifert, B., Albrecht, W., Richau, K., Lendlein, A., Groth, T. %D 2008 %J Journal of Biomaterials Science - Polymer Edition %N 7 %P 837-852 %R doi:10.1163/156856208784613523 %T Poly(ether imide) membranes: studies on the effect of surface modification and protein pre-adsorption on endothelial cell adhesion, growth and function %U https://doi.org/10.1163/156856208784613523 7 %X Poly(ether imide) (PEI) membranes of which the surface was modified with carboxylic groups were tested in comparison to pure PEI and poly(ethylene terephtalate) (PET) for their ability to support attachment, growth and function of human umbilical vein endothelial cells (HUVEC) with respect to endothelization of the above materials. Flat sheet PEI membranes were modified by covalent binding of iminodiacetic acid (IDA) for different periods of time (1 to 30 min) to obtain surfaces with various content of carboxylic groups. In addition, fibronectin (FN) and fibrinogen (FNG) pre-adsorption on the various membranes were studied for their effect on HUVEC behaviour. The results show a decreased protein adsorption and HUVEC adhesion, growth and function in terms of prostacyclin production with an increase in carboxylic groups. Pre-adsorption of the membranes with FN or FNG promoted activity of HUVEC, which became superior to cells on PET. FN-coated membranes were found to be a better substrate for HUVEC adhesion and prostacyclin production, while on FNG-coated membranes cells grew better. Overall it can be concluded that PEI is a promising materials for endothelial cells immobilization as it is needed for improving the haemocompatibility of cardiovascular devices. %0 conference lecture %@ %A Entrialgo-Castano, M., Lendlein, A., Hofmann, D. %D 2008 %J Conference on Molecular Simulations in Biosystems and Material Science %T Molecular Dynamics Simulation and Quantum Mechanical Studies of the Hydrolytic Degradation of Aliphatic Polyesters %U %X %0 conference lecture %@ %A Lange, C., Rumpler, M., Manjubula, I., Kratz, K., Lendlein, A., Fratzl, P. %D 2008 %J Osteologie-Tagung %T Porengroesse und Substratsteifigkeit beeinflussen die dreidimensionale Gewebeentstehung in vitro %U %X %0 journal article %@ 1022-1360 %A Entrialgo, M., Salvucci, A.E., Lendlein, A., Hofmann, D. %D 2008 %J Macromolecular Symposia %N 1 %P 47-64 %R doi:10.1002/masy.200850908 %T An Atomistic Modeling and Quantum Mechanical Approach to the Hydrolytic Degradation of Aliphatic Polyesters %U https://doi.org/10.1002/masy.200850908 1 %X This paper reports computational simulations at two different scales employed to investigate the hydrolytic degradation of two homopolyesters: polyglycolide, PGA and poly(L-lactide), PLLA. Atomistic bulk models were used to investigate the dry and various hydrated states of the two systems. In addition, the first moments of contact between the polymers and water were studied employing atomistic interface models. A higher affinity of water to polyglycolide in comparison with poly(L-lactide) was observed, while diffusion of water was found to be lower in the first polymer. Quantum chemical calculations for the first step of the water-assisted hydrolysis revealed a higher resistance to hydrolytical scission of the L-lactyl units in comparison to glycolyl units. %0 conference poster %@ %A Razzaq, M., Behl, M., Lendlein, A. %D 2008 %J Polydays 2008 %T Effect of Magnetic Nanoparticles on Thermal and Mechanical Properties of Shape-Memory Polymer Networks %U %X %0 conference lecture %@ %A Schroeter, M., Mendez, J.D., Berg, O.van den, Capadona, J.R., Weder, C., Lendlein, A. %D 2008 %J Polydays 2008 %T Development of New Polymer Materials with Electrical Conductivity and Stimuli-sensitive Attributes %U %X %0 journal article %@ 1099-498X %A Li, W., Ma, N., Ong, L.-L., Kaminski, A., Skarbal, C., Ugurlan, M., Lorenz, P., Gatzen, H.-H., Luetzow, K., Lendlein, A., Puetzer, B., Li, R.-K., Steinhoff, G. %D 2008 %J The Journal of Gene Medicine %N 8 %P 897-909 %R doi:10.1002/jgm.1208 %T Enhanced thoracic gene delivery by magnetic nanobead-mediated vector %U https://doi.org/10.1002/jgm.1208 8 %X MNB-mediated gene delivery could comprise a promising method for gene delivery to the lung and the heart. %0 conference poster %@ %A Zotzmann, J., Behl, M., Kelch, S., Choi, N.-Y., Lendlein, A. %D 2008 %J Tag der Chemie, VCI Berlin Brandenburg %T Multifunctional Polymer Networks from Poly(rac-lactide)-b-poly(propylene oxide)-b-poly(rac-lactide) dimethacrylates %U %X %0 conference lecture (invited) %@ %A Lendlein, A., Behl, M. %D 2008 %J 3rd International Conference Smart Materials, Structures and Systems %T Shape-Memory Polymers for Biomedical Applications %U %X %0 journal article %@ 0939-6411 %A Kulkarni, A., Reiche, J., Hartmann, J., Kratz, K., Lendlein, A. %D 2008 %J European Journal of Pharmaceutics and Biopharmaceutics %N 1 %P 46-56 %R doi:10.1016/j.ejpb.2007.05.021 %T Selective enzymatic degradation of poly (Epsilon-caprolactone) containing multiblock copolymers %U https://doi.org/10.1016/j.ejpb.2007.05.021 1 %X The hydrolytic and Pseudomonas lipase catalysed enzymatic degradation was studied for PDC multiblock copolymers consisting of poly(e-caprolactone) (PCL) segments and poly(p-dioxanone) (PPDO) segments with variable composition. The enzymatic degradation of these multiblock copolymers is significantly accelerated by Pseudomonas lipase in contrast to the hydrolytic degradation where the deg-radation behaviour is determined by the PPDO segments. Degradation time intervals up to 200 h are selected, where the PPDO segments remain stable and do not contribute to the degradation process. A linear correlation between weight loss and increasing PCL content of the multiblock copolymers was found. X-ray diffraction data confirm that both crystalline and amorphous PCL are attacked by the enzymes. SEM cross-section images reveal that Pseudomonas lipase penetrates into the PDC polymers. The present study impressively demonstrates that selective enzymatic degradation of PCL containing multifunctional polymers is a beneficial tool for controlling their degradation properties. %0 book part %@ %A Behl, M., Langer, R., Lendlein, A. %D 2008 %J Intelligent Materials, Chapter 12 %P 301-316 %T Intelligent Materials: Shape-Memory Polymers %U %X %0 conference lecture %@ %A Lendlein, A. %D 2008 %J GDCH-Jahrestagung, Fachgruppe Chemieunterricht %T Wie Polymernetzwerkarchitekturen die aktive Bewegung von Polymeren beeinflussen %U %X %0 journal article %@ 0032-3861 %A Karimi, M., Albrecht, W., Heuchel, M., Weigel, T., Lendlein, A. %D 2008 %J Polymer %N 10 %P 2587-2594 %R doi:10.1016/j.polymer.2008.03.036 %T Determination of solvent/polymer interaction parameters of moderately concentrated polymer solutions by vapor pressure osmometry %U https://doi.org/10.1016/j.polymer.2008.03.036 10 %X The paper describes the application of vapor pressure osmometry (VPO) to determine solvent/polymer interaction parameters for various polymer solutions containing high-molecular weight polymers in the semi-diluted concentration range. The theoretical basis for the data evaluation is the Flory–Huggins (FH) model and a virial expansion up to the third virial term. For validation already well characterized polymer/solvent systems poly(vinylpyrrolidone)/water, polysulfone/N,N-dimethylformamide (DMF), and poly(ether sulfone)/DMF were investigated. In the second part interaction parameters of poly(ether imide) (PEI) in solvents with technical relevance for membrane formation (DMF, N-methylpyrrolidone (NMP), N,N-dimethylacetamide (DMAc)) were examined at different concentrations and temperatures. The results document that VPO is a fast and promising method for characterization of semi-diluted polymer solutions containing polymers with higher molecular weight. Results confirm the decrease of solvent power for PEI in the series: NMP > DMAc > DMF. %0 journal article %@ 0041-1345 %A Furlani, D., Klopsch, C., Gaebel, R., Ugurlucan, M., pittermann, D., Klee, K., Wagner, K., Li, W., Wang, W., Ong, L.L., Nizze, H., Titze, U., Luetzow, K., Lendlein, A., Steinhoff, G., Ma, N. %D 2008 %J Transplantation Proceedings %N 4 %P 962-966 %R doi:10.1016/j.transproceed.2008.03.033 %T Intracardiac Erythropoietin Injection Reveals Antiinflammatory Potential and Improved Cardiac Functions Detected by Forced Swim Test %U https://doi.org/10.1016/j.transproceed.2008.03.033 4 %X did not lead to intramural thrombus formation %0 book part %@ %A Behl, M., Lendlein, A. %D 2008 %J Yearbook Of Science & Technology 2008 %P 293-296 %T Shape-Memory Polymers %U %X Shape-memory polymers are an emerging class of active polymers which can change their shape in a predefined way when exposed to an appropriate stimulus. Shape-memory research was initialized by the development of thermo-sensitive materials. These materials had a dual shape capability as they could move from a first to a second shape. This concept was extended to other stimuli by either indirect thermal actuation or direct actuation by addressing stimuli-sensitive functional groups on the molecular level. Recently, triple shape materials were introduced, which can perform two shape changes after subsequent temperature increases. In this paper fundamental aspects of the molecular design of suitable polymer architectures, tailored creation of the different shapes and the quantification of the dual as well as the triple shape effect are presented. %0 journal article %@ 0040-6090 %A Reiche, J., Kulkarni, A., Kratz, K., Lendlein, A. %D 2008 %J Thin Solid Films %N 24 %P 8821-8828 %R doi:10.1016/j.tsf.2007.11.053 %T Enzymatic Monolayer Degradation Study of Multiblock Copolymers consisting of Poly(epsilon-caprolactone) and Poly(p-dioxanone) Blocks %U https://doi.org/10.1016/j.tsf.2007.11.053 24 %X monolayers is developed. %0 conference lecture %@ %A Luetzow, K., Albrecht, W., Weigel, T., Seifert, B., Ma, N., Lendlein, A. %D 2008 %J TERMIS-EU 2008 Meeting %T Poly(ether imide) membranes as a matrix for cell-polymer interactions %U %X %0 conference lecture %@ %A Reiche, J., Kulkarni, A., Sokolov, I., Kratz, K., Lendlein, A. %D 2008 %J 11th European Conference on Organized Films %T Hydrolytic Fragmentation of Polymer Chains %U %X %0 conference lecture %@ %A Lendlein, A. %D 2008 %J Institutspraesentation fuer die Firma Synthes %T Welcome to the Campus Teltow of the GKSS Research Center %U %X %0 review %@ 1369-7021 %A Lendlein, A. %D 2008 %J Materials Today %N 3 %P 59 %R doi:10.1016/S1369-7021(08)70027-0 %T Review: Textiles come to life %U https://doi.org/10.1016/S1369-7021(08)70027-0 3 %X No abstract %0 conference lecture %@ %A Tronci, G., Lendlein, A. %D 2008 %J SFB Vortrag %T Biomimetic scaffold systems to support regeneration of bone defects having overcritical size %U %X %0 conference lecture %@ %A Wang, W., Li, W., Ong, L.-L., Furlani, D., Gabel, R., Ugurlucan, M., Klopsch, C., Lorenz, P., Luetzow, K., Lendlein, A., Ma, N., Steinhoff, G. %D 2008 %J Annual Meeting, European Society for Artificial Organs, ESAO 2008 %T Collagen and Fibronectin Substrates Mediated Local SDF-1 Gene Expression Induces Stem Cells Homing %U %X %0 conference poster %@ %A Kommareddy, K.P., Lange, C., Manjubala, I., Rumpler, M., Fratzl, P., Cui, J., Kratz, K., Lendlein, A. %D 2008 %J Polydays 2008 %T Growth of Extracellular Matrix tissue controlled by pore size and stiffness of scaffolds %U %X %0 journal article %@ 1662-0356 %A Lendlein, A., Behl, M. %D 2008 %J Advances in Science and Technology, Smart Materials & Micro/Nanosystems %P 96-102 %R doi:10.4028/www.scientific.net/AST.54.96 %T Shape-memory Polymers for Biomedical Applications %U https://doi.org/10.4028/www.scientific.net/AST.54.96 %X applications. Furthermore triple-shape polymers will be introduced, that have the capability to perform two subsequent shape changes. Thus enabling more complex movements of a polymeric material. %0 conference lecture %@ %A Hiebl, B., Rickert, D., Fuhrmann, R., Jung, F., Lendlein, A., Franke, R.-P. %D 2008 %J MRS Fall Meeting 2008, Symposium HH, Advances in Material Design for Regenerative Medicine, Drug Delivery, and Targeting/Imaging %T Tissue Integration of Two Different Shape-Memory Polymers with Poly(e-Caprolactone) Switching Segment in Rats %U %X %0 conference lecture %@ %A Razzaq, M.Y., Behl, M., Kratz, K., Lendlein, A. %D 2008 %J MRS Fall Meeting 2008, Symposium HH, Advances in Material Design for Regenerative Medicine, Drug Delivery, and Targeting/Imaging %T Controlled Actuation of Shape-Memory nanocomposites by Application of an Alternating Magnetic Field %U %X %0 conference lecture %@ %A Kratz, K., Voigt, U., Wagermaier, W., Lendlein, A. %D 2008 %J MRS Fall Meeting 2008, Symposium HH, Advances in Material Design for Regenerative Medicine, Drug Delivery, and Targeting/Imaging %T Shape-memory Properties of Multiblock Copolymers Consisting of Poly(?-pentadecalactone) Hard Segments and Crystallisable Poly(e-caprolactone) Switching Segments %U %X %0 conference lecture %@ %A Hofmann, D., Pimthon, J., Willumeit, R., Lendlein, A. %D 2008 %J MRS Fall Meeting 2008, Symposium HH, Advances in Material Design for Regenerative Medicine, Drug Delivery, and Targeting/Imaging %T Computational modeling of anionic and zwitterionic lipid bilayers for investigating surface activities of bioactive molecules %U %X %0 conference paper %@ %A Behl, M., Bellin, I., Lelch, S., Wagermaier, W., Lendlein, A. %D 2008 %J Advances in Material Design for Regenerative Medicine, Drug Delivery, and Targeting/Imaging, MRS Symposium Proceedings, MRS Fall Meeting 2008 %P HH01-02 %R doi:10.1557/PROC-1140-HH01-02 %T Dual and Triple Shape Capability of AB Polymer Networks based on Poly(e-caprolactone)dimethacrylates %U https://doi.org/10.1557/PROC-1140-HH01-02 %X %0 journal article %@ 0940-0079 %A Seifert, B., Lendlein, A. %D 2008 %J BIOforum %P 22-24 %T Hilfe zur Selbsthilfe im Heilungsprozess durch Regenerative Therapien Tissue Engineering und induzierte Autoregeneration %U %X Die Gewebezüchtung, neudeutsch Tissue Engineering, und die induzierte Autoregeneration sind Teilgebiete der Regenerativen Medizin, die sich mit der Therapie verschiedener Erkrankungen durch die Wiederherstellung von funktionsgestörten Zellen, Gewebe und Organe beschäftigt. Dabei ist die große Herausforderung: eine endgültige Heilung statt lebenslanger Behandlung. Diese ehrgeizigen Ziele werden im Bereich des Tissue Engineering durch die Züchtung von neuem Gewebe aus patienteneigenen Zellen angegangen. Im Rahmen der induzierten Autoregeneration werden körpereigene Regenerationsprozesse stimuliert. %0 lecture %@ %A Lendlein, A. %D 2008 %J %T Shape Memory Polymers %U %X %0 conference lecture %@ %A Behl, M., Lendlein, A. %D 2008 %J Vortrag DFG-SPP 1420-Projekt %T Hierarchically structuring multiphase polymer networks in layer systems for enabling thermally-triggered complex shape changes %U %X %0 conference lecture %@ %A Cui, J., Lendlein, A., Fratzl, P. %D 2008 %J SFB Vortrag %T Regulation of the Biosynthesis of Extracellular Matrix Components by Biomaterials of Different Geometry and Stiffness %U %X %0 conference poster %@ %A Kratz, K., Reiche, J., Kulkarni, A., Lendlein, A. %D 2008 %J Polydays 2008 %T Biodegradation Behaviour of Thermo-Sensitive Dual Shape Polymers desired for Biomedical Applications %U %X %0 conference object %@ 1937-3341 %A Borstlap, J., Lendlein, A., Duda, G., Mundlos, S., Sittinger, M., Dirnagl, U., Gerlach, J., Reinke, P., Volk, H.-D. %D 2008 %J Tissue Engineering A %N 5 %P 792 %R doi:10.1089/tea.2008.1504 %T Translating Novel Scientific Findings into Regenerative Therapies %U https://doi.org/10.1089/tea.2008.1504 5 %X No abstract %0 conference lecture %@ %A Neffe, A.T., Hanh, B.D., Steuer, S., Lendlein, A. %D 2008 %J MRS Fall Meeting 2008 %T Triple-Functional Polymer Networks Combining Controlled Drug Release, Biodegradation, and Shape Memory Capability %U %X %0 conference lecture %@ %A Neffe, A.T., Tronci, G., Roessle, M., Lendlein, A. %D 2008 %J 17. Nachwuchswissenschaftler-Symposium Bioorganische Chemie %T Dimensionally Stable Scaffolds from Gelatin-Based Polymer System %U %X %0 conference lecture %@ %A Borstlap, J., Lendlein, A., Duda, G., Mundlos, S., Sittinger, M., Dirnagl, U., Gerlach, J., Reinke, P., Volk, H.-D. %D 2008 %J TERMIS-EU 2008 Meeting %T Translating Novel Scientific Findings into Regenerative Therapies %U %X %0 conference lecture %@ %A Lendlein, A. %D 2008 %J First German-Sino Symposium %T Biomaterials for Regenerative Medicine %U %X %0 lecture %@ %A Neffe, A.T., Lendlein, A. %D 2008 %J %T Wirkstoffdesign und Freisetzungssysteme %U %X %0 conference poster %@ %A Neffe, A.T., Tronci, G., Roessle, M., Lendlein, A. %D 2008 %J MRS Fall Meeting 2008, SESSION HH5: Poster Session: Functional Materials and Drug Delivery Systems %T Tailored Scaffolds from a Gelatin-based Polymer System: Influence of the Molecular Architecture on Material Properties %U %X %0 conference lecture %@ %A Lendlein, A. %D 2008 %J Weltforum der Medizin - Internationale Fachmesse mit Kongress, MEDICA 2008 %T Biomaterialien fuer die Regenerative Medizin - Aktueller Status und Perspektiven %U %X %0 conference lecture %@ %A Neffe, A.T., Hanh, B.D., Steuer, S., Kelch, S., Lendlein, A. %D 2008 %J Materials Science and Engineering, MSE 2008 %T Triple-Functional Polymer Networks Combining Controlled Drug Release, Biodegradation, and Shape Memory Capability %U %X %0 conference lecture (invited) %@ %A Lendlein, A., Franke, R.-P., Jung, F., Behl, M. %D 2008 %J Lenkungsausschusssitzung HGF %T Program Regenerative Medicine %U %X %0 conference lecture %@ %A Behl, M., Bellin, I., Kelch, S., Wagermaier, W., Lendlein, A. %D 2008 %J MRS Fall Meeting 2008, Symposium HH, Advances in Material Design for Regenerative Medicine, Drug Delivery, and Targeting/Imaging %T Dual and Triple Shape Capability of AB Polymer Networks based on Poly(Epsilon-caprolactone)dimethacrylates %U %X %0 journal article %@ 1438-1656 %A Kelch, S., Choi, N.-Y., Wang, Z., Lendlein, A. %D 2008 %J Advanced Engineering Materials %N 5 %P 494-502 %R doi:10.1002/adem.200700339 %T Amorphous, Elastic AB Copolymer Networks from Acrylates and Poly[(L-lactide)-ran-glycolide]dimethacrylates %U https://doi.org/10.1002/adem.200700339 5 %X No abstract %0 journal article %@ 1369-703X %A Heilmann, K., Groth, T., Schossig, M., Lendlein, A., Micheel, B. %D 2007 %J Biochemical Engineering Journal %N 3 %P 301-308 %R doi:10.1016/j.bej.2007.01.035 %T Modulation of Hybridoma cell growth and antibody production by coating cell culture materials with extracellular matrix proteins %U https://doi.org/10.1016/j.bej.2007.01.035 3 %X However, the presence of β1-integrin on the cell surface was shown, which should enable hybridoma cells to bind fibronectin. We propose, therefore, that fibronectin adsorption to cell culture materials may be a promising approach to enhance the production of monoclonal antibodies by cultivated hybridoma cells. %0 journal article %@ 1386-0291 %A Rickert, D., Scheithauer, M., Coskun, S., Kelch, S., Lendlein, A., Franke, R.-P. %D 2007 %J Clinical Hemorheology and Microcirculation %N 4 %P 301-311 %T The influence of a multifunctional, polymeric biomaterial on the concentration of acute phase proteins in an animal model %U 4 %X The concentrations of the acute phase proteins α1-Acid Glycoprotein (AAG) and haptoglobin were determined in Sprague-Dawley-rats after implantation of a novel biodegradable multifunctional polymeric biomaterial for the reconstruction of a gastric wall defect (polymer group; n=42). For comparison, the concentrations of AAG and haptoglobin were measured as well after primary wound closure of the gastric wall defect without biomaterial implantation (control group; n=21) and in rats without any surgical procedure (baseline group; n=21). The implantation periods were 1 week, 4 weeks and 6 months. The concentrations of AAG and haptoglobin were measured by an ELISA assay. Gastrointestinal complications like fistula, perforation or peritonitis did not occur in any of the animals. No statistically significant differences in the concentrations of AAG and haptoglobin were detected between the polymer and the control group. An adequate mechanical stability of the polymeric biomaterial was detectable under the extreme pathophysiological conditions of the stomach milieu. In further examinations the correlation between the intraperitoneal cytokine levels of the animals and the following systemic inflammatory markers should be analysed. Further investigations are needed to analyse the mechanisms of the tissue integration of a biomaterial as well as the process of the tissue remodeling and the influence of the immune system on these mechanisms. The knowledge of these processes is necessary to adapt the multifunctional biomaterial and prepare it thus for the use and implantation in different body locations and to develop novel therapeutical options in medicine. %0 journal article %@ 1744-683X %A Choi, N.-Y., Lendlein, A. %D 2007 %J Soft Matter %N 7 %P 901-909 %R doi:10.1039/b702515g %T Degradable Shape-Memory Polymer Networks from Oligo[(L-lactide)-ran-glycolide]dimethacrylates %U https://doi.org/10.1039/b702515g 7 %X In this paper degradable shape-memory polymer networks synthesized from oligo[(L-lactide)-ran-glycolide]dimethaycrylates are introduced. The macrodimethacrylates are prepared via a two-step synthesis: hydroxy telechelic oligo[(L-lactide)-ran-glycolide]s with number average molecular weights Mn ranging from 1000 to 5700 g mol–1 were synthesized by ring-opening polymerization from L,L-dilactide, diglycolide and ethylene glycol as initiator using dibutyltin oxide as the catalyst. These oligodiols are reacted with methacryloyl chloride resulting in terminal methacrylate groups. Crosslinking of macrodimethacrylates is performed under exposure to UV light without applying a photo initiator. The polymer networks obtained are transparent and hydrolytically degradable. While the mechanical properties at temperatures higher than Tg depend on crosslinking density, Tg is almost constant at about 55 °C. The shape-memory functionality of the amorphous polymer network was investigated by cyclic, thermomechanical tests under the systematic variation of different programming parameters. Good shape-memory properties with strain recovery rates close to 100% were obtained under stress-controlled programming. Under strain-controlled conditions, it needs to be considered that relatively high stresses can be generated during programming. Potential biomedical applications are intelligent implants or smart drug release systems. %0 journal article %@ 0021-9290 %A Luetzow, K., Klein, F., Weigel, T., Apostel, R., Weiss, A., Lendlein, A. %D 2007 %J Journal of Biomechanics %P S 80-S 88 %R doi:10.1016/j.jbiomech.2007.02.022 %T Formation of poly(Epsilon-caprolactone) scaffolds loaded with small molecules by integrated processes %U https://doi.org/10.1016/j.jbiomech.2007.02.022 %X Cell stimulation by bioactive molecules has become an important tool in tissue engineering. The homogeneous incorporation of such molecules within the bulk of a polymer-based scaffold compared to surface coating is considered advantageous for most applications and minimizes a burst effect. An efficient way of bulk loading is the incorporation of these molecules during the scaffold formation process. In this paper, two different integrated processes for the preparation of scaffolds from poly(ε-caprolactone) (PCL) loaded with a small molecule are investigated. Both formation and loading of the scaffold is carried out in a single-step process. Sudan Red G was selected as a model compound for lipophilic small molecules. A freeze drying and pressure quench (PQ) formation process was selected, and the influence of the small molecule on the formation processes and on the morphology of the obtained scaffold was evaluated and compared. It could be shown for both processes that the formation of loaded scaffolds is possible, and that the small molecule has a very high impact on the foam morphology. In case of the freeze-drying (FD) method, only a load of 1 wt% Sudan Red G was incorporated within the bulk and showed no influence on the foam morphology. In the case of PQ foaming, an incorporation of 43 wt% Sudan Red G was achieved (although tiny crystal needles of the small molecule were found on the surface) and a strong effect on the foam morphology was found. This paper presents an efficient method of incorporating small molecules by integrated processes. %0 journal article %@ 0002-7863 %A Kummerloewe, G., Auernheimer, J., Lendlein, A., Luy, B. %D 2007 %J Journal of the American Chemical Society %N 19 %P 6080-6081 %R doi:10.1021/ja071248s %T Stretched Poly(acrylonitrile) as a Scalable Alignment Medium for DMSO %U https://doi.org/10.1021/ja071248s 19 %X Stretched gels made of cross-linked poly(acrylonitrile) swollen in DMSO are introduced as freely scalable and widely applicable alignment media for the measurement of anisotropic NMR parameters such as residual dipolar couplings. The production process using accelerated electrons for cross-linking is described, NMR signals originating from the alignment medium are characterized, as well as methods for their suppression, and RDC measurements are demonstrated for a number of example molecules. %0 journal article %@ 0959-9428 %A Bellin, I., Kelch, S., Lendlein, A. %D 2007 %J Journal of Materials Chemistry %P 2885-2891 %R doi:10.1039/b702524f %T Dual-Shape Properties of Triple-Shape Polymer Networks with Crystallizable Network Segments and Grafted Side Chains %U https://doi.org/10.1039/b702524f %X Triple-shape materials have recently been introduced as a promising class of active polymers, that can change on demand from a first shape (A) to a second shape (B) and from there to a third shape (C). Here, the dual-shape capability of such a triple-shape polymer network system having two distinct melting transitions is investigated by cyclic, thermomechanical experiments. These multiphase polymer networks are synthesized by photopolymerization from poly(ethylene glycol) monomethyl ether monomethacrylate and poly(e-caprolactone) dimethacrylate as crosslinker. While their permanent shape is determined by the chemical crosslinks formed during network preparation, the two different crystallizable phases can be used to fix other temporary shapes. When programmed appropriately in a two-step thermomechanical process these materials can exhibit a triple-shape effect. Here, one-step programming methods for dual-shape effects are applied to these polymer networks under variation of process parameters, especially thermal conditions. In this way, crystalline phases formed by both segments can be used either individually or simultaneously to fix a temporary second shape. The permanent shape can be recovered by heating, exceeding a specific switching temperature. This switching temperature correlates with the melting transition of the related domain, if one domain is used for fixation. If both domains are used, the switching temperature correlates with the higher melting temperature. %0 conference lecture (invited) %@ %A Kratz, K., Reiche, J., Kulkarni, A., Lendlein, A. %D 2007 %J 3rd World Congress on Regenerative Medicine %T Biodegradation studies of aliphatic polyesters using the Langmuir monolayer technique %U %X %0 conference lecture %@ %A Luetzow, K., Klein, F., Weigel, T., Apostel, R., Weiss, A., Lendlein, A. %D 2007 %J World Congress Regenerative Medicine %T Loading of Scaffolds with small molecules by integrated processes %U %X %0 conference lecture %@ %A Zlatanov, I., Seifert, B., Groth, T., Lendlein, A., Altankov, G. %D 2007 %J 9th International Conference on Geometry, Integrability and Quantization %T Fractal Dynamics of Beta 1-Integrins in Living Fibroblasts %U %X %0 journal article %@ 1549-3296 %A Rickert, D., Franke, R.-P., Lendlein, A., Kelch, S., Moses, M.A. %D 2007 %J Journal of Biomedical Materials Research A %N 2 %P 558-569 %R doi:10.1002/jbm.a.31250 %T Influence of the surface structure of a multiblock copolymer on the cellular behavior of primary cell cultures of the upper aerodigestive tract in vitro %U https://doi.org/10.1002/jbm.a.31250 2 %X The influence of the surface topography of a biodegradable copolymer on adhesion, proliferation, and cellular activity of primary cell cultures of the upper aerodigestive tract (ADT) was investigated. On the basis of the important functions of matrix metalloproteinases (MMPs) and their endogenous inhibitors, tissue inhibitor of MMPs (TIMPs) in regulating extracellular matrix remodeling, cellular adhesion and growth, the appearance and kinetics of these enzymes were investigated in primary cells of the upper ADT seeded on different surfaces of a polymeric biomaterial. Primary cell cultures of the upper ADT of Sprague-Dawley rats were seeded on different surfaces (smooth versus rough surface) of a biodegradable multiblock copolymer and on polystyrene surface as control. Conditioned media of the primary cells were analyzed for MMPs and TIMPs by both zymography and radiometric enzyme assay. Cell adhesion and proliferation as well as the kinetics of appearance and activity level of MMP-1, MMP-2, and TIMPs were significantly different depending on the cell type and the surface structure of the multiblock copolymer. In this study, the data obtained indicated that surface topography governed the biological response to biomaterials. Knowledge as to how cells interact with the interface of biomaterials will be necessary in order to eventually design the ideal surface of biomaterials, which will be both tissue and organ-optimized in order to best provide clinicians with specific and viable novel therapeutical options in medicine. %0 journal article %@ 0959-9428 %A Grablowitz, H., Lendlein, A. %D 2007 %J Journal of Materials Chemistry %N 38 %P 4050-4056 %R doi:10.1039/b707104c %T Synthesis and characterization of Alpha, Omega-dihydroxy-telechelic oligo(p-dioxanone) %U https://doi.org/10.1039/b707104c 38 %X The homopolymer of 1,4-dioxane-2-one (pDO) is well known as an established biomaterial, especially for degradable surgical sutures. Well-defined ,-dihydroxy telechelics based on pDO are introduced in this paper. pDO was synthesized via a one step reaction modified to a literature procedure with a yield of 50–60%. The monomer was polymerized in bulk to oligomeric products via ring-opening polymerization. The polymerization was performed without or with dibutyltin oxide as catalyst using low molecular weight alcohols as initiators. The oligomeric products have number average molecular weights (Mn) between 1800 g mol–1 and 4200 g mol–1. They were soluble in 1,2-dichloroethane or chloroform as common solvents for further reaction in solution. The ,-dihydroxy-functionality of the obtained telechelics was investigated by MALDI-TOF MS and 1H NMR spectroscopy. Polymerization in the presence of the catalyst lead to macrocyclic byproducts which have been detected by MALDI-TOF MS. The telechelics were semicrystalline with melting points Tm between 86 °C and 95 °C, increasing with increasing molecular weight. %0 journal article %@ 0142-2421 %A Kulkarni, A., Reiche, J., Lendlein, A. %D 2007 %J Surface and Interface Analysis :SIA %N 9 %P 740-746 %R doi:10.1002/sia.2580 %T Hydrolytic degradation of poly(rac-lactide) and poly[(rac-lactide)-co-glycolide] at the air-water interface %U https://doi.org/10.1002/sia.2580 9 %X The understanding of the simultaneous transport and chain-scission phenomena involved in the hydrolysis of bulk-degrading polymers requires the experimental separation of chain cleavage and water diffusion. The hydrolytic chain cleavage of poly(rac-lactide) rac-(PLA) and poly[(rac-lactide)-co-glycolide] (PLGA) is analysed on the basis of monolayer degradation experiments combined with an improved data reduction procedure. Different, partly contradictory models of the hydrolytic degradation and erosion mechanism of PLA and PLGA, namely random chain scission and chain-end scission, are discussed in the literature. The instantaneous linear area reduction observed for the polymer Langmuir films indicates a chain-end scission mechanism. As monolayers of end-capped and non-end-capped polymers degrade with exactly the same rate, the observed differences in the degradation kinetics of bulk samples do clearly result from differences in the water penetration into these polymers. A pronounced auto-inhibition effect is observed for the polymers degraded at initially high pH of the aqueous subphase in the absence of buffers. %0 conference lecture %@ %A Lendlein, A. %D 2007 %J Wollenberger Seminar %T Active Biomaterials %U %X %0 journal article %@ 1066-5099 %A Li, W., Ma, N., Ong, L.L., Nesselmann, C., Klopsch, C., Ladilov, Y., Furlani, D., Piechaczek, C., Moebius, J.M., Luetzow, K., Lendlein, A., Stamm, C., Li, R.-K., Steinhoff, G. %D 2007 %J Stem Cells %N 8 %P 2118-2127 %R doi:10.1634/stemcells.2006-0771 %T Bcl-2 Engineered MSCs Inhibited Apoptosis and Improved Heart Function %U https://doi.org/10.1634/stemcells.2006-0771 8 %X Engraftment of mesenchymal stem cells (MSCs) derived from adult bone marrow has been proposed as a potential therapeutic approach for postinfarction left ventricular dysfunction. However, limited cell viability after transplantation into the myocardium has restricted its regenerative capacity. In this study, we genetically modified MSCs with an antiapoptotic Bcl-2 gene and evaluated cell survival, engraftment, revascularization, and functional improvement in a rat left anterior descending ligation model via intracardiac injection. Rat MSCs were manipulated to overexpress the Bcl-2 gene. In vitro, the antiapoptotic and paracrine effects were assessed under hypoxic conditions. In vivo, the Bcl-2 gene-modified MSCs (Bcl-2-MSCs) were injected after myocardial infarction. The surviving cells were tracked after transplantation. Capillary density was quantified after 3 weeks. The left ventricular function was evaluated by pressure-volume loops. The Bcl-2 gene protected MSCs against apoptosis. In vitro, Bcl-2 overexpression reduced MSC apoptosis by 32% and enhanced vascular endothelial growth factor secretion by more than 60% under hypoxic conditions. Transplantation with Bcl-2-MSCs increased 2.2-fold, 1.9-fold, and 1.2-fold of the cellular survival at 4 days, 3 weeks, and 6 weeks, respectively, compared with the vector-MSC group. Capillary density in the infarct border zone was 15% higher in Bcl-2-MSC transplanted animals than in vector-MSC treated animals. Furthermore, Bcl-2-MSC transplanted animals had 17% smaller infarct size than vector-MSC treated animals and exhibited functional recovery remarkably. Our current findings support the premise that transplantation of antiapoptotic gene-modified MSCs may have values for mediating substantial functional recovery after acute myocardial infarction. %0 conference lecture %@ %A Lendlein, A., Behl, M., Kamlage, S. %D 2007 %J NATO Advanced Research Workshop on Nanoengineered Systems for Regenerative Medicine %T The Nature of the Thermal Transition influences the Shape-memory Behavior of Polymer Networks %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2007 %J 4th Sino-German Symposium on Polymer Science, SGSPS 2007 %T Shape Memory %U %X %0 journal article %@ 0304-8853 %A Li, W., Nesselmann, C., Zhou, Z., Ong, L.L., Oeri, F., Tang, G., Kaminski, A., Luetzow, K., Lendlein, A., Liebold, A., Stamm, C., Wang, J., Steinhoff, G., Ma, N. %D 2007 %J Journal of Magnetism and Magnetic Materials %N 1 %P 336-341 %R doi:10.1016/j.jmmm.2006.11.201 %T Gene Delivery to the heart by magnetic nanobeads %U https://doi.org/10.1016/j.jmmm.2006.11.201 1 %X Gene delivery with non-viral gene vectors to the cardiovascular system suffers from low transfection efficiency. In this study, magnetic fields were investigated to assist cardiovascular gene delivery via magnetic nanobeads both in vitro and in vivo. The magnetic field was provided with a 1120 mT Nd–Fe–B permanent magnet while complexes of poly-ethyleneimine (PEI) and various DNA plasmids were conjugated with magnetic nanobeads (MNB) using a Sulfo-NHS-LC-Biotin linker. In vitro results showed that transfection in two cell lines was 30–80-fold higher in magnetically conjugated MNB/PEI/DNA complexes than transfection from PEI/DNA complexes alone. Similarly, in vivo results using mouse models showed 72 h after injection observable gene expression in the heart with conjugated MNB/PEI/DNA complexes, but barely with PEI/DNA complexes alone. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2007 %J Treffen der Leiter der Institute und Einrichtungen der Helmholz Gemeinschaft - Forschungsbereich Gesundheit %T Gesundheit - Programm Regenerative Medizin %U %X %0 conference lecture %@ %A Weigel, T., Albrecht, W., Luetzow, K., Klein, F., Lendlein, A. %D 2007 %J Technologietage Teltow %T Herstellung poroeser Formkoerper fuer biomedizinische Anwendungen %U %X %0 journal article %@ 0935-8943 %A Rickert, D., Lendlein, A., Kelch, S., Coskun, S., Scheithauer, M.O. %D 2007 %J Laryngo-Rhino-Otologie %N 7 %P 507-514 %R doi:10.1055/s-2007-966091 %T Polymerere Biomaterialien in der Kopf-Hals-Chirurgie: Erste Ergebnisse der Biokompatibilitaetstestung eines abbaubaren Polymers im Tiermodell %U https://doi.org/10.1055/s-2007-966091 7 %X Neuartige, multifunktionale, polymere Biomaterialien können zur Entwicklung neuer therapeutischer Optionen in der Kopf-Hals-Chirurgie beitragen. Die Rekonstruktion von Defekten des oberen Aerodigestivtraktes mit Hilfe eines geeigneten Biomaterials würde eine neue Therapiestrategie in der Behandlung von Speichelfisteln darstellen. Methoden: Ein polymeres Biomaterial wurde in einem randomisierten, prospektiven Tierversuch untersucht. 12 Sprague-Dawley-Ratten wurden für die Polymerimplantation verwendet, bei 6 Versuchstieren wurde eine Sham-Operation durchgeführt. In der Implantatgruppe wurde ein standardisierter, durchgreifender Magenwanddefekt gesetzt, der mit einem elastischen Copolymernetzwerk verschlossen wurde. In der Kontrollgruppe wurde ein primärer Wundverschluss des Magenwanddefektes ohne Biomaterialimplantation durchgeführt. Die Implantations- bzw. Versuchsdauer betrug 7, 14 und 30 Tage. Ergebnisse: Bei keinem Versuchstier traten gastrointestinale Komplikationen wie Fisteln oder Peritonitiden auf. Sowohl in der Implantat- als auch in der Kontrollgruppe war makroskopisch und histologisch ein regulärer Wundheilungsverlauf nachweisbar. Schlussfolgerung: Aufgrund der nachweisbaren chemischen, hydrolytischen und mechanischen Stabilität des Polymernetzwerkes unter den extremen enzymatischen, chemischen und mechanischen Bedingungen des Magenmilieus, ist davon auszugehen, dass das Biomaterial auch im Bereich des oberen Aerodigestivtraktes eine adäquate Stabilität besitzt. %0 journal article %@ 0376-7388 %A Albrecht, W., Schauer, J., Weigel, T., Richau, K., Groth, T., Lendlein, A. %D 2007 %J Journal of Membrane Science %N 1-2 %P 10-18 %R doi:10.1016/j.memsci.2006.12.014 %T Modification of poly(ether imide) membranes with brominated polyvinylpyrrolidone %U https://doi.org/10.1016/j.memsci.2006.12.014 1-2 %X The work refers to the hydrophilization of microporous poly(ether imide) (PEI) membranes by coating with brominated poly(vinylpyrrolidone) (BrPVP). The PEI microporous membranes were first aminated with poly(ethylene imine) (Pei) and then coated with BrPVP. PVP layer on the membrane prepared from a high molecular weight BrPVP was resistant against washing out with aqueous solutions, which resulted from the stabilization of the gel layer, whereas the layers prepared from unbrominated or low molecular weight BrPVP were not completely stabilized. Separation profiles of resulting membranes can be tailored according to the requirements of application. BrPVP was prepared by the reaction of PVP with bromine or hydrobromic acid. It was possible to prepare BrPVP containing large amounts of bromine, which was rather strongly fixed to the PVP chain. The analysis of the products of the same reaction carried out with 1-ethyl-2-pyrrolidone (EP) (a low molecular weight model of PVP) indicated that the BrPVP comprises addition complexes between HBr molecules and carbonyl groups of PVP. The new PVP coated membranes are promising candidates for the blood contacting applications. %0 journal article %@ 0376-7388 %A Albrecht, W., Santoso, F., Luetzow, K., Weigel, T., Schomaecker, R., Lendlein, A. %D 2007 %J Journal of Membrane Science %N 1-2 %P 145-157 %R doi:10.1016/j.memsci.2007.01.027 %T Preparation of aminated microfiltration membranes by degradable functionalization using plain PEI membranes with various morphologies %U https://doi.org/10.1016/j.memsci.2007.01.027 1-2 %X The work describes the functionalization of microporous poly(ether imide) membranes with ultrafiltration separation profile by degradative functionalization using a two-step treatment process, which leads to strongly aminated membranes with microfiltration properties. Membranes with different morphology and ultrafiltration separation profile were prepared. In the first step, the pore system was opened by treatment with diethylenetriamine (DETA) which was followed by a treatment with high molecular poly(ethylene imine) to increase the amount of amine groups. Results verify that macrovoidal structures are more beneficial than sponge-like structures because of their strongly opened pores while only a small reduction in membrane thickness occurred. The separation properties of the virgin membrane have only a marginal influence on the pore opening process because of the leveling off the separation properties after a short treatment time. The number of covalently bound amine functions could be strongly increased by a second step functionalization process using a high-molar volume polyamine as a modifier which indicates the presence of residual imide groups of the basic polymer after the primary DETA treatment. Moreover the prepared membranes are suited for steam sterilization. These characteristics suggest a beneficial application in adsorptive separation processes. %0 journal article %@ 1525-7797 %A Kelch, S., Steuer, S., Schmidt, A.M., Lendlein, A. %D 2007 %J Biomacromolecules %N 3 %P 1018-1027 %R doi:10.1021/bm0610370 %T Shape-memory Polymer Networks from Oligo[(epsilon-hydroxycaproate)-co-glycolate]-dimethacrylates and Butylacrylate with Adjustable Hydrolytic Degradation Rate %U https://doi.org/10.1021/bm0610370 3 %X Degradable shape-memory polymer networks intended for biomedical applications were synthesized from oligo[(-hydroxycaproate)-co-glycolate]dimethacrylates with glycolate contents between 0 and 30 mol % using a photopolymerization process. In addition AB copolymer networks were prepared by adding 60 wt % n-butyl acrylate as comonomer. All synthesized polymer networks are semicrystalline at room temperature. A melting transition Tm between 18 and 53 C which can be used as switching transition for the shape-memory effect can be attributed to the crystalline poly(-hydroxycaproate) phase. At temperatures below Tm the elastic properties are dominated by these physical cross-links. At temperatures higher than Tm the E modulus of the amorphous polymer networks is lowered by up to 2 orders of magnitude, depending on the chemical cross-link density. Copolymer networks based on macrodimethacrylates with a Mn of up to 13 500 g·mol-1 and a maximum glycolate content of 21 mol % show quantitative strain recovery rates in stress-controlled cyclic thermomechanical experiments. Hydrolytic degradation experiments of polymer networks performed in phosphate buffer solution at 37 C show that the degradation rate can be accelerated by increasing the glycolate content and decelerated by the incorporation of n-butyl acrylate. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2007 %J Sommerakademie der Studienstiftung des deutschen Volkes %T Aktiv bewegliche Kunststoffe %U %X %0 journal article %@ 1744-683X %A Behl, M., Lendlein, A. %D 2007 %J Soft Matter %N 1 %P 58-67 %R doi:10.1039/b610611k %T Actively Moving Polymers %U https://doi.org/10.1039/b610611k 1 %X The ability of polymers to move actively in response to an external stimulus such as heat or light is of high scientific and technological significance. In any instance stimuli-responsive effects on the molecular level are converted into macroscopic movement, whereby generally two different moving behaviors have to be differentiated for polymer-based materials: the shape-memory effect and the shape-changing capability. Basic concepts for the molecular design of suitable polymer architectures for shape-memory polymers as well as tailored programming processes are presented. The thermally-induced shape-memory effect of polymers is described as well as the extension of this concept to other stimuli than heat. Indirect actuation of the thermally-induced effect by IR-irradiation, electric current, humidity or alternating magnetic fields are outlined as well as recent work on light-induced shape-memory polymers. For shape-changing polymers, two basic concepts are presented: shape changes occurring during phase orientation of liquid crystal elastomers (LCE) and the photomechanical effect based on photoisomerization of moieties, such as azo-groups incorporated in suitable polymer systems. %0 journal article %@ 1369-7021 %A Behl, M., Lendlein, A. %D 2007 %J Materials Today %N 4 %P 20-28 %R doi:10.1016/S1369-7021(07)70047-0 %T Shape Memory Polymers %U https://doi.org/10.1016/S1369-7021(07)70047-0 4 %X be multifunctional. Besides their dual-shape capability, these active materials are biofunctional or biodegradable. Potential applications for such materials as active medical devices are highlighted. %0 conference lecture %@ %A Entrialgo, M., Lendlein, A., Hofmann, D. %D 2007 %J Molecular Basis, Production and Applications of Biopolymers in Biotechnology, Biomedicine and Nanobiomaterials, 4th European Symposium on Biopolymers, ESBP 07 %T An Atomistic and Quantum Mechanical Approach to the Hydrolytic Degradation of Polyesters %U %X %0 conference lecture (invited) %@ %A Lendlein, A., Behl, M. %D 2007 %J NanoMat 8 Szene, Forschungszentrum Karlsruhe %T Actively Moving Polymers %U %X %0 conference poster %@ %A Weigel, T., Kratz, K., Mohr, R., Lendlein, A. %D 2007 %J 3rd World Congress of Regenerative Medcine %T Shape-Memory Polymer Nanocomposites Responsive to Alternating Magnetic Fields %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2007 %J Urania %T Koennen sich Kunststoffe bewegen? %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2007 %J Institutspraesentation %T Regenerative Medizin %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2007 %J BCRT - Research - Seminar %T Bio - Engineering %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2007 %J BVP - Strategie Workshop %T Langfristige Strategie fuer die Polymerforschung %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2007 %J Fruehjahrstagung des Arbeitskreises AKF %T Shape-Memory Polymers %U %X %0 conference lecture %@ %A Lendlein, A. %D 2007 %J Regenerative Medizin, Medizinische Hochschule %T Formgedaechtnis Nahtmaterial %U %X %0 conference lecture (invited) %@ %A Lendlein, A., Franke, R.-P. %D 2007 %J Sommerakademie der Studienstiftung des deutschen Volkes %T Biomaterialien: Von der Synthese zum intelligenten Implantat %U %X %0 conference lecture %@ %A Entrialgo, M., Lendlein, A., Hofmann, D. %D 2007 %J Tag der Chemie 2007 %T Hydrolytic Degradation of Aliphatic Polyesters: Molecular Modeling and Quantum Mechanical Investigations %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2007 %J Lehrerfortbildung %T Active Biomaterials %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2007 %J 1st Thai-German Symposium on Regenerative Medicine %T Regenerative Therapies in Germany - Present Status and Perspectives of Regenerative Medicine in Germany %U %X %0 conference lecture %@ %A Rickert, D., Fuhrmann, R., Hiebl, B., Lendlein, A., Franke, R.-P. %D 2007 %J NATO Advanced Research Workshop on Nanoengineered Systems for Regenerative Medicine %T Results of Biocompatibility Testing of Novel, Multifunctional Polymeric Implant Materials In-Vitro and In-Vivo %U %X %0 conference lecture %@ %A Wischke, C., Neffe, A., Steuer, S., Lendlein, A. %D 2007 %J 6th International Nanomedicine and Drug Delivery Symposium, Nano DDS 2008 %T Evaluation of a degradable shape-memory polymer network as matrix for controlleddrug release %U %X functionalities, i.e., a shape-memory effect combined with biodegradability and controlled drug release. %0 lecture %@ %A Lendlein, A., Schroeter, M. %D 2007 %J %T Polymere in der Medizin %U %X %0 journal article %@ 1076-3279 %A Boese, G., Trimpert, C., Albrecht, W., Malsch, G., Groth, T., Lendlein, A. %D 2007 %J Tissue Engineering %N 12 %P 2995-3302 %R doi:10.1089/ten.2006.0442 %T Membranes from Acrylonitrile-Based Polymers for Selective Cultivation of Human Keratinocytes %U https://doi.org/10.1089/ten.2006.0442 12 %X transplants. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2007 %J Engineering Life Symposium – smart life live smart %T Actively Moving Polymers %U %X %0 journal article %@ 1746-0751 %A Weigel, T., Kratz, K., Mohr, R., Lendlein, A. %D 2007 %J Regenerative Medicine %N 5 %P 712-713 %T Shape memory polymer nanocomposites responsive to alternating magnetic fields %U 5 %X Typically heat [1] or irradiation by light [2] is used to initiate the shape-shifting process. A remote triggering of the shape memory effect could improve the application possibilities decisively, and composites with magnetic nanoparticles should be able to trigger this effect by heating in alternating magnetic fields [3]. %0 conference lecture %@ %A Lendlein, A. %D 2007 %J Berlin-Brandenburg Reception at MEDICA %T Innovative Medical Devices based on Biomaterial Development %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2007 %J 1st Thai-German Symposium on Regenerative Medicine %T Active Polymers for Biomedical Applications %U %X %0 journal article %@ 1746-0751 %A Luetzow, K., Klein, F., Weigel, T., Apostel, R., Weiss, A., Lendlein, A. %D 2007 %J Regenerative Medicine %N 5 %P 560 %T Loading of scaffolds with small molecules by integrated processes %U 5 %X Cell stimulation by bioactive molecuies has become an important tooi in tissue engineering. The homogeneous incorporation of such molecuies within the bull< of a polymer based scaffold compared to surface coating is considered advanrageous for most applications and minimizes a burst effect. Objective of this paper is the buik loading of a scafToid by incorporating these molecuies during the scaffoid Formation process. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2007 %J Symposium fuer Materialforschung %T Materialforschung fuer Innovationen in der Region Berlin / Brandenburg %U %X %0 conference lecture %@ %A Schroeter, M., Lendlein, A. %D 2007 %J Helmholtz Programm, Funktionale Werkstoffsysteme, AEM- Zwischenbegutachtung %T Funktionalisierte Materialien %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2007 %J German- Israeli- Nonomedicine Workshop %T Multifunctional heterogeneous Polymer Systems %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2007 %J Wissenschaftliches Kolloquium des Adolf-Martens-Fonds %T Multifunktionale Polymersysteme fuer medizinische Anwendungen %U %X %0 conference lecture %@ %A Lendlein, A. %D 2007 %J BCRT- Retreat, Klausurtagung %T Zentrum fuer Biomaterialentwicklung %U %X %0 journal article %@ 0743-7463 %A Kulkarni, A., Reiche, J., Kratz, K., Kamusewitz, H., Sokolov, I.M., Lendlein, A. %D 2007 %J Langmuir %N 24 %P 12202-12207 %R doi:10.1021/la701523e %T Enzymatic chain scission kinetics of poly(Epsilon-caprolactone) monolayers %U https://doi.org/10.1021/la701523e 24 %X The hydrolytic and enzymatic degradation behavior of poly(-caprolactone) (PCL) is investigated using the Langmuir monolayer technique, and an improved data acquisition and data reduction procedure is presented. Hydrolytic and enzymatic monolayer degradation experiments of PCL with various molecular weights by Pseudomonas cepacia lipase have been carried out to analyze the influence of subphase pH, subphase temperature, enzyme concentration, and the packing density of polymer chains on the degradation kinetics. The enzymatic monolayer degradation results in an exponential increase in the number of dissolved degradation fragments with increasing degradation time, which confirms random chain scission to be the dominant scission mechanism. The increase in the enzymatic scission rate constant with decreasing initial average molecular weight of the polymers is assigned to the influence of the area density of polar terminal groups on the substrate-enzyme complex formation. %0 journal article %@ 1048-6690 %A Neffe, A.T., Lendlein, A. %D 2007 %J Medical Device Technology %N 6 %P 14-19 %T Tailoring established polymers for medical applications %U 6 %X Polymers can be tailored for specific biomedical applications by synthesis, processing or surface modification. Knowledge-based choice of comonomers for acrylonitrile based copolymers influences the interaction profile with specific cell lines and blood. Processing or surface modification of poly(ether imides) results in materials having complex three-dimensional structures and/or specific adsorption profiles. Potential applications are dialysis, gas separation, cell/tissue systems, apheresis, and bioreactors. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2007 %J 3. WING - Konferenz %T Materialwissenschaften weisen Wege in die Zukunft - Visionen und Perspektiven fuer die Gesundheitsforschung %U %X %0 conference lecture %@ %A Lendlein, A., Behl, M. %D 2007 %J BCRT- Retreat, Klausurtagung %T Field B: Bio- Engineering %U %X %0 journal article %@ 0023-5563 %A Lendlein, A., Kelch, S., Kratz, K. %D 2006 %J Kunststoffe : KU %N 2 %P 54-59 %T Kunststoffe mit programmiertem Gedaechtnis: Implantate %U 2 %X Kunststoffe mit Formgedächtnis können sich an ihre ursprüngliche Form erinnern und nehmen diese nach Anwendung von Temperaturerhöhung oder Bestrahlung mit UV-Licht wieder ein. Bedeutung für die Medizintechnik, z.B. in der minimalinvasiven Chirurgie, haben besonders multifunktionale Materialien, die eine unerwartete Kombination von Funktionalitäten, wie Biofunktionalität, kontrollierte Wirkstofffreisetzung, Degradierbarkeit und Formgedächtnis, aufweisen. %0 journal article %@ 1616-0177 %A Reiche, J., Kulkarni, A., Hartmann, J., Kratz, K., Lendlein, A. %D 2006 %J Biomaterialien %N S 1 %P 107 %T Monolayer Degradation Kinetics of Polymer Implant Materials %U S 1 %X No abstract %0 conference lecture %@ %A Blomenkamp, I., Bertmer, M., Buda, A., Lendlein, A. %D 2006 %J Polydays 2006 %T Amorphous, Biodegradable Shape-Memory Polymer Networks: Characterization with Solid-State NMR %U %X %0 conference lecture %@ %A Kulkarni, A., Reiche, J., Koehler, A., Kratz, K., Hartmann, J., Lendlein, A. %D 2006 %J Polydays 2006 %T Chain Scission Kinetics of Polymers Derived from Langmuir-Monolayer- and Bulk Degradation %U %X %0 conference lecture %@ %A Kulkami, A., Reiche, J., Sokolov, I., Kratz, K., Lendlein, A. %D 2006 %J International Symposium Biomaterials and Hamburg Macromolecular Symposium 2006 %T Kinetics of enzymatic degradation of polymer monolayers %U %X %0 journal article %@ 0160-564X %A Luetzow, K., Weigel, T., Lendlein, A. %D 2006 %J Artificial Organs %N 10 %P 764-769 %R doi:10.1111/j.1525-1594.2006.00298.x %T Poly(ether imide) scaffolds as multifunctional materials for potential applications in Regenerative Medicine %U https://doi.org/10.1111/j.1525-1594.2006.00298.x 10 %X surfaces. %0 journal article %@ 0935-9648 %A Jiang, H., Kelch, S., Lendlein, A. %D 2006 %J Advanced Materials %N 11 %P 1471-1475 %R doi:10.1002/adma.200502266 %T Polymers Move in Response to Light %U https://doi.org/10.1002/adma.200502266 11 %X Significant advances have recently been made in the development of functional polymers that are able to undergo light-induced shape changes. The main challenge in the development of such polymer systems is the conversion of photoinduced effects at the molecular level to macroscopic movement of working pieces. This article highlights some selected polymer architectures and their tailored functionalization processes. Examples include the contraction and bending of azobenzene-containing liquid-crystal elastomers and volume changes in gels. We focus especially on light-induced shape-memory polymers. These materials can be deformed and temporarily fixed in a new shape. They only recover their original, permanent shape when irradiated with light of appropriate wavelengths. Using light as a trigger for the shape-memory effect will extend the applications of shape-memory polymers, especially in the field of medical devices where triggers other than heat are highly desirable. %0 journal article %@ 1438-1656 %A Choi, N.-Y., Kelch, S., Lendlein, A. %D 2006 %J Advanced Engineering Materials %N 5 %P 439-445 %R doi:10.1002/adem.200600020 %T Synthesis, Shape-Memory Functionality and Hydrolytical Degradation Studies on Polymer Networks from Poly(rac-lactide)-b-poly(propylene oxide)-b-poly(rac-lactide) dimethacrylates %U https://doi.org/10.1002/adem.200600020 5 %X No abstract %0 journal article %@ 0013-5585 %A Rickert, D., Scheithauer, M., Coskun, S., Lendlein, A., Kelch, S., Franke, R.-P. %D 2006 %J Biomedizinische Technik / Biomedical Engineering %N 3 %P 116-124 %R doi:10.1515/BMT.2006.020 %T Erste Ergebnisse zur Untersuchung der Stabilitaet und Gewebeintegration eines abbaubaren, elastischen Copolymers im Tiermodell / First results of the investigation of the stability and tissue integration of a degradable, elastomeric copolymer in an animal model %U https://doi.org/10.1515/BMT.2006.020 3 %X No abstract %0 journal article %@ 1558-3724 %A Yoshida, M., Langer, R.S., Lendlein, A., Lahann, J. %D 2006 %J Polymer Reviews %N 4 %P 347-375 %R doi:10.1080/15583720600945394 %T From advanced biomedical coatings to multi-functionalized biomaterials %U https://doi.org/10.1080/15583720600945394 4 %X In this review, current activities in the development of active biomaterials related to bio‐interfacial design as well as novel concepts for smart polymer systems are highlighted. For instance, advanced biomedical coatings, including vapor‐based polymer coatings for the controlled attachment of biomolecules, and temperature‐responsive coatings for tissue engineering are outlined. Moreover, recent trends with the fabrication of “smart,” switchable surfaces, such as conformationally switching monolayers, will be reviewed. Specific focus will further be given to multi‐functionalized biomaterials including shape‐memory polymers that undergo specific changes in shape in response to stimuli like heat or light. This novel class of intelligent materials highlights a recent trend in biomaterial development targeting is the extension of this concept to multi‐functionalization. In particular, the combination of biodegradability and shape‐memory effects opens a range of opportunities for biomedical applications including intelligent sutures or stents. %0 conference poster %@ %A Bellin, K., Lendlein, A. %D 2006 %J Polydays 2006 %T Amorphous, Biodegradable Poly(ester-urethane) Networks with Shape-Memory Properties %U %X %0 journal article %@ 0160-564X %A Vienken, J., Sengbusch, G.v., Lendlein, A., Marx, U. %D 2006 %J Artificial Organs %N 10 %P 727-729 %R doi:j.1525-1594.2006.00294.x %T Regenerative medicine - Membranes and scaffolds %U https://doi.org/j.1525-1594.2006.00294.x 10 %X No abstract %0 journal article %@ %A Lendlein, A. %D 2006 %J Science Allemagne: Technisches und wissenschaftliches Informationsblatt %N 4 %P 12-13 %T Neues Programm der Helmholtz-Gemeinschaft im Bereich Regenerative Medizin %U 4 %X %0 journal article %@ %A Lendlein, A. %D 2006 %J Science Allemagne: Technisches und wissenschaftliches Informationsblatt %N 4 %P 14-15 %T Der Arbeitskreis "Regenerative Medizin" %U 4 %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J 17th European Students Conference %T Biomaterials for Regenerative Medicine %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J Regenerative Medicine - A Discussion on Research Relating to Advanced Therapies %T Aspects of Biomaterials %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J DGM-Tag 2006, Deutsche Gesellschaft fuer Materialkunde %T (Mulfi)funktionalisierte Polymere fuer Anwendungen in der Medizin %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J DIF-Fachkonferenz, Kunststoffe in der Medizintechnik, Deutsches Industrieforum %T Multifunktionale Polymersysteme fuer medizinische Anwendungen %U %X %0 conference lecture %@ %A Kelch, S., Choi, N.-Y., Lendlein, A. %D 2006 %J Polydays 2006 %T Multifunctional Polymer Networks from Poly(rac-lactide)-b-poly(propylene oxide)-b-poly(rac-lactide) dimethacrylates %U %X %0 conference lecture %@ %A Lucka-Gabor, M., Moneke, M., Mohr, R., Kratz, K., Weigel, T., Lendlein, A. %D 2006 %J Polydays 2006 %T Characterization of Morphology in Shape Memory Compounds and their Warming and Deformation Upon Inductive Heating %U %X %0 journal article %@ 1862-4243 %A Lendlein, A., Kelch, S., Kratz, K. %D 2006 %J Kunststoffe International %N 2 %P 54-59 %T Implantats: Plastics with Programmed Memory %U 2 %X Plastics with shape-memory can "remember" their original shape and resume it again on exposure to heat or UV radiation. Multifunctional materials with an unexpected combination of functionalities, such as biofunctionality, controlled active ingredient release, degradability and shape-memory have a special importance for medical technology, e.g. in minimally invasive surgery. %0 conference lecture %@ %A Kelch, S., Lendlein, A. %D 2006 %J Workshop Regenerative Medizin, MDC %T Multifunctional Polymeric Biomaterials %U %X %0 journal article %@ 0027-8424 %A Mohr, R., Kratz, K., Weigel, T., Lucka-Gabor, M., Moneke, M., Lendlein, A. %D 2006 %J Proceedings of the National Academy of Sciences of the United States of America: PNAS %N 10 %P 3540-3545 %R doi:10.1073/pnas.0600079103 %T Initiation of shape-memory effect by inductive heating of magnetic nanoparticles in thermoplastic polymers %U https://doi.org/10.1073/pnas.0600079103 10 %X triggering are comparable to those obtained by increasing the environmental temperature. %0 conference lecture (invited) %@ %A Hofmann, D., Entrialgo, M., Pimthon, J., Lendlein, A. %D 2006 %J Advanced Membrane Technology %T Atomistic molecular modelling of biomaterials %U %X %0 conference lecture %@ %A Rickert, D., Scheithauer, M., Kelch, S., Franke, R.-P., Lendlein, A. %D 2006 %J 77. Jahresversammlung der Deutschen Gesellschaft fuer Hals-Nasen-Ohrenheilkund, Kopf- und Halschirurgie %T Vergleichende Untersuchungen zur Mukosarekonstruktion im Tiermodell durch ein neuartiges Formgedaechtnis­polymer und Poly(L-lactid) %U %X %0 journal article %@ 1618-7881 %A Lendlein, A. %D 2006 %J Kunststoff Trends %P 24-25 %T Gut kombiniert - Multifunktionale Polymere %U %X Ein aktueller Trend in der Materialforschung ist die Entwicklung von multifunktionalen Materialien, die eine ungewöhnliche Kombination von Funktionalitäten, wie z.B. Biofunktionalität, Degradierbarkeit oder Formgedächtnis aufweisen. die Entwicklung solcher multifunktionaler Materialien wird dabei von der Anwendung geleitet. Im Gegensatz zu intrinsischen Materialeigenschaften ergeben sich Funktionalitäten aus der Kombination von Materialien und Prozessen. %0 journal article %@ 0032-1338 %A Kratz, K., Lendlein, A. %D 2006 %J Der Plastverarbeiter %N 4 %P 50 %T Rohstoffe - Beruehrungslos Verformen, Nanokomposite aendern ihre Form im Magnetfeld %U 4 %X eröffnen sich neue Einsatzmöglichkeiten in der Medizin. %0 conference lecture %@ %A Entrialgo-Castano, M., Lendlein, A., Hofmann, D. %D 2006 %J Polydays 2006 %T Molecular Modeling Investigations on Hydrolytically Degradable Polyesters %U %X %0 conference poster %@ %A Kratz, K., Mohr, R., Lendlein, A., Moneke, M., Lucka-Gabor, M. %D 2006 %J Polydays 2006 %T Properties of Shape-Memory Polymer Nanocompounds Responsive to Alternating Magnetic Fields %U %X %0 conference lecture %@ %A Lendlein, A. %D 2006 %J Sino-German Workshop on Regenerative Medicine %T (Multi)functional Polymers and Scaffold Systems for Regenerative Medicine %U %X %0 conference lecture %@ %A Schroeter, M., Mendez, J., Lendlein, A., Weder, C. %D 2006 %J Polydays 2006 %T Synthesis and Optical Properties of New Hyperbranched Poly(p-Phenylene Ethynylene)s Prepared via Different A2 + B3 Approaches %U %X %0 conference lecture %@ %A Lendlein, A. %D 2006 %J Vortragsveranstaltung am MDC %T Ueberblick ueber Forschungsaktivitaeten in der Regenerativen Medizin und im Institut fuer Polymerforschung %U %X %0 journal article %@ 1438-1656 %A Entrialgo-Castano, M., Hofmann, D., Lendlein, A. %D 2006 %J Advanced Engineering Materials %N 5 %P 434-439 %R doi:10.1002/adem.200600021 %T Molecular Modeling Investigations of Dry and Two Water-Swollen States of Biodegradable Polymers %U https://doi.org/10.1002/adem.200600021 5 %X No abstract %0 conference poster %@ %A Reiche, J., Kulkarni, A., Hartmann, J., Kratz, K., Lendlein, A. %D 2006 %J 2nd International Symposium Interface Biology of Implants %T Monolayer Degradation Kinetics of Polymer Implant Materials %U %X %0 conference lecture %@ %A Reiche, J., Koehler, A., Kulkarni, A., Kratz, K., Lendlein, A. %D 2006 %J European Conference on Organized Films, ECOF-10 %T Degradation Kinetics of Polymers obtained via the Lanmuir-Monolayer method %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J GDCh-Vortrag, Bayer Material Science AG %T Multifunktionale Polymersysteme fuer Anwendungen in der Medizin %U %X %0 conference lecture %@ %A Reissfelder, C., Kelch, S., ritz, J.-P., Seifert, B., Lendlein, A., Buhr, H.J. %D 2006 %J 123. Kongress der Deutschen Gesellschaft fuer Chirurgie, Chirurgisches Forum %T Evaluation der in vitro und in vivo Eigenschaften eines neuen, vollstaendig degradierbaren Nahtmaterials mit Formgedaechtniseffekt fuer die Visceralchirurgie %U %X %0 journal article %@ 0376-7388 %A Albrecht, W., Luetzow, K., Weigel, T., Groth, T., Schossig, M., Lendlein, A. %D 2006 %J Journal of Membrane Science %N 1-2 %P 106-115 %R doi:10.1016/j.memsci.2005.09.043 %T Development of highly porous microparticles from poly(ether imide) prepared by a spraying/coagulation process %U https://doi.org/10.1016/j.memsci.2005.09.043 1-2 %X In this work, a novel support for apheresis application is presented which is based on microporous particles that were prepared from poly(ether imide) by a spraying/coagulation process. The polymer solution is sprayed through a hollow needle to form droplets and the droplets were vitrified by a nonsolvent induced phase separation. Results of the investigation of the spraying step and of the phase inversion step as well as characteristic data of the prepared particles are presented. Data of the particle characteristics verify that this technique is suitable to prepare highly porous support particles, which have a high accessibility of their internal pore system. %0 journal article %@ 0376-7388 %A Albrecht, W., Schauer, J., Weigel, T., Lendlein, A. %D 2006 %J Journal of Membrane Science %N 1-2 %P 49-59 %R doi:10.1016/j.memsci.2005.06.015 %T Preparation of novel composite membranes: Reactive coating on microporous poly(ether imide) support membranes %U https://doi.org/10.1016/j.memsci.2005.06.015 1-2 %X Poly(ether imide) asymmetric membranes can be covalently functionalized with aminic modifiers. When poly(ethylene imine), i.e., a polyvalent high molecular weight modifier, is used, the functionalization is connected with the support membrane pore-filling in a very thin layer. The poly(ethylene imine) layer is, however, not stables at increased temperatures and does not fill completely large pores. The layer can be stabilized by crosslinking with oligomeric poly(ethylene glycol) diglycidyl ether (PEGDGE), but this does not improve the coverage of large pores. The poly(ethylene imine) functionalized membrane can be stabilized, however, by reactive coating with copolymers of methacrolein with 1-vinylpyrrolidone instead stabilization with PEGDGE with a coverage of the large pores. The copolymers having various ratios of both polymeric units were prepared by free radical polymerization. The methacrolein units of copolymers, which comprised predominantly 1-vinyl-2-pyrrolidone units, had aldehyde groups in a free reactive form. These aldehyde groups react readily with the amine groups of the poly(ethylene imine) layer, while 1-vinylpyrrolidone units render the coating hydrophilic. The membranes coated under optimal conditions had nanofiltration separation properties at high water fluxes. Good adhesion between the coating layer and the support membrane, which results from the covalent binding, should allow separations under harsh conditions. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J 2nd International Symposium Interface Biology of Implants %T Multifunctional Polymers for biomedical applications %U %X %0 journal article %@ 0937-4477 %A Rickert, D., Lendlein, A., Peters, I., Moses, M.A., Franke, R.-P. %D 2006 %J European Archives of Oto-Rhino-Laryngology %N 3 %P 215-222 %R doi:10.1007/s00405-005-0950-1 %T Biocompatibility Testing of Novel Multifunctional Polymeric Biomaterials for Tissue Engineering Applictions in Head and Neck Surgery: An Overview %U https://doi.org/10.1007/s00405-005-0950-1 3 %X Biomaterial research and tissue engineering are rapidly growing scientific fields that need an interdisciplinary approach where clinicians should be included from the onset. Biocompatibility testing in vitro and in vivo comprise the agarose-overlay test, the MTT test, direct cell seeding tests and the chorioallantoic membrane test for angiogenic effects, among others. Molecular biology techniques such as real-time polymerase chain reaction and microarray technology facilitate the investigation of tissue integration into biomaterials on a cellular and molecular level. The physicochemical characterization of biomaterials is conducted using such methods as X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Excellent biocompatibility and biofunctionality were demonstrated for a series of recently developed multifunctional biodegradable, polymeric biomaterials both in vitro and in vivo. Novel, multifunctional polymeric biomaterials offer a highly specific adjustment to the physiological, anatomical and surgical requirements and can thereby facilitate new therapeutic options in head and neck surgery. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J New strategies in regenerative medicine: the marriage of biology and materials science, ESF-Workshop FZK %T Intelligent Biomaterials %U %X %0 lecture %@ %A Lendlein, A. %D 2006 %J %T Aktuelle Themen der Polymerchemie %U %X %0 journal article %@ %A Volk, H.D., Duda, G., Lendlein, A. %D 2006 %J InterLink; Linking the International Community of TERMIS %N iii %P 15-20 %T Newsletter: Berlin-Brandenburg Center for Regenerative Therapies (BCRT) %U iii %X %0 conference lecture %@ %A Lendlein, A. %D 2006 %J Eroeffnung des Zentrums fuer Biomaterialentwicklung %T Zentrum fuer Biomaterialentwicklung %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J BioClub %T Funktionalisierte Polymersysteme fuer Anwendungen in der Medizin %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J Strategieworkshop Helmholtz-Gemeinschaft / Bayer AG %T Biomaterials functionalised Polymer Systems %U %X %0 conference lecture %@ %A Lendlein, A. %D 2006 %J SFB Vortrag %T Biomimetic scaffold systems to support regeneration of bone defects having overcritical size %U %X %0 conference lecture %@ %A Lendlein, A. %D 2006 %J Center for Biomaterial Development, Vortrag an der Nankai-University %T (Multi)functional Polymers and Scaffold Systems for Regenerative Medicine %U %X %0 lecture %@ %A Lendlein, A. %D 2006 %J %T Polymers for Biomedical Applications %U %X %0 conference lecture %@ %A Kelch, S., Malsch, G., Seifert, B., Albrecht, W., Lendlein, A. %D 2006 %J 25. Jahrestagung der Deutschen Gesellschaft fuer Klinische Mikrozirkulation und Haemorheologie %T Cell and Blood Compatibility of Polyacrylonitrile (PAN) and PAN-Copolymers %U %X %0 journal article %@ 0027-8424 %A Bellin, I., Kelch, S., Langer, R., Lendlein, A. %D 2006 %J Proceedings of the National Academy of Sciences of the United States of America: PNAS %N 48 %P 18043-18047 %R doi:10.1073/pnas.0608586103 %T Polymeric triple-shape materials %U https://doi.org/10.1073/pnas.0608586103 48 %X Shape-memory polymers represent a promising class of materials that can move from one shape to another in response to a stimulus such as heat. Thus far, these systems are dual-shape materials. Here, we report a triple-shape polymer able to change from a first shape (A) to a second shape (B) and from there to a third shape (C). Shapes B and C are recalled by subsequent temperature increases. Whereas shapes A and B are fixed by physical cross-links, shape C is defined by covalent cross-links established during network formation. The triple-shape effect is a general concept that requires the application of a two-step programming process to suitable polymers and can be realized for various polymer networks whose molecular structure allows formation of at least two separated domains providing pronounced physical cross-links. These domains can act as the switches, which are used in the two-step programming process for temporarily fixing shapes A and B. It is demonstrated that different combinations of shapes A and B for a polymer network in a given shape C can be obtained by adjusting specific parameters of the programming process. Dual-shape materials have already found various applications. However, as later discussed and illustrated by two examples, the ability to induce two shape changes that are not limited to be unidirectional rather than one could potentially offer unique opportunities, such as in medical devices or fasteners. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J Deutschland und Korea: Partner in Forschung und Entwicklung, BMBF-Auftaktveranstaltung %T Regenerative Medicine in the Helmholtz Association of German Research Centres %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J Seminarvortrag am Institut fuer Polymerforschung %T Actively Moving Polymers %U %X %0 conference lecture %@ %A Lendlein, A. %D 2006 %J Regenerative Medicine as a challenge for the European Research Area, Workshop %T Bio-Engineering %U %X %0 journal article %@ 1743-4440 %A Weigel, T., Schinkel, G., Lendlein, A. %D 2006 %J Expert Review of Medical Devices %N 6 %P 835-851 %R doi:10.1586/17434440.3.6.835 %T Design and preparation of polymeric scaffolds for tissue engineering %U https://doi.org/10.1586/17434440.3.6.835 6 %X special regard to their utility in the area of tissue engineering. %0 lecture %@ %A Lendlein, A. %D 2006 %J %T Makromolekulare Chemie funktionalisierter Materialien mit Relevanz in der Medizin %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J Kolloquium der Materialwissenschaft %T Shape-memory polymer systems %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J Knee 2006 %T Biomaterials for Tissue Regeneration %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J Vortrag an der Donau-Universitaet %T Intelligente Polymere %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J BioTOP Informationsveranstaltung, Vorstellung des Quadriga Masterplans Biotechnologie/Biomedizin %T Regenerative Therapien - Vorstellung BCRT %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J Advanced Membrane Technology III Congress - Engineering Conferences International %T Membranes for the application in Regenerative Medicine %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J BIONNALE %T Aspekte in der Biomaterialforschung fuer die Regenerative Medizin %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J Bio-Systems, MPG-Workshop %T Active Polymers %U %X %0 lecture %@ %A Lendlein, A. %D 2006 %J %T Multifunktionale Polymersysteme fuer Anwendungen in der Medizin, Ringvorlesung %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J Mitgliederversammlung der Wissenschaftspressekonferenz, Geoforschungszentrum %T Kunststoffe bewegen %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2006 %J Biomaterials, 29. Hamburger Makromolekulare Symposium %T Actively Moving Polymers %U %X %0 journal article %@ 1616-5187 %A Trimpert, C., Boese, G., Albrecht, W., Richau, K., Weigel, T., Lendlein, A., Groth, T. %D 2006 %J Macromolecular Bioscience %N 4 %P 274-284 %R doi:10.1002/mabi.200500238 %T Poly(ether imide) Membranes Modified with Poly(ethylene imine) as Potential Carriers for Epidermal Substitutes %U https://doi.org/10.1002/mabi.200500238 4 %X Poly(ether imide) (PEI) membranes were modified with a linear low-molecular weight (PETIM_0.6) and a branched high-molecular weight poly(ethylene imine) (PETIM_60). The membrane surfaces became more hydrophilic and the zeta potentials were shifted from negative to positive zeta values after immobilisation of both PETIM. These measurements also indicated the presence of a swollen surface layer in the case of PETIM_60, while a regular structuring of the surface was observed with scanning force microscopy for PETIM_0.6. A human keratinocyte cell line HaCaT was cultured on the different membranes. It was found that HaCaT cell growth was stimulated by PETIM_0.6. Cells reached earlier confluence on this substratum, while their growth was inhibited on a PEI membrane modified with PETIM_60, which makes PEI membranes modified with PETIM_0.6 a promising material for in vitro culture of epidermal transplants. %0 conference lecture %@ %A Lendlein, A. %D 2006 %J 25. Jahrestagung der Deutschen Gesellschaft fuer Klinische Mikrozirkulation und Haemorheologie, DGKMH %T Funktionalisierte Polymere fuer Anwendungen in der Medizin %U %X %0 conference lecture %@ %A Lendlein, A. %D 2005 %J Quo vadis Chirurgia 2005 %T (Multi-) Funktionale Materialien und deren Innovationsmaterial in der Medizin %U %X %0 journal article %@ 1619-4772 %A Lendlein, A., Schroeter, M. %D 2005 %J Krankenhaus, Technik + Management %N 4 %P 16-18 %T Resorbierbare Formgedaechtniskunststoffe fuer medizinische Anwendungen %U 4 %X Man mag es kaum für möglich halten, aber es ist wahr: Ein Kunststoff kann eine Formgedächtnisfunktionalität aufweisen, wenn er entsprechend verarbeitet und programmiert wurde. Die Vorteile, die sich für die moderne Medizin von Morgen daraus ergeben, sind vielfältig. %0 book part %@ %A Lendlein, A., Kelch, S., Kratz, K., Schulte, J. %D 2005 %J Encyclopedia of Materials: Science and Technology (Second Edition) %P 1-9 %R doi:10.1016/B0-08-043152-6/02033-7 %T Shape-memory Polymers %U https://doi.org/10.1016/B0-08-043152-6/02033-7 %X %0 lecture %@ %A Lendlein, A. %D 2005 %J %T Kunststoffe als Implantatmaterialien - Konzepte fuer (Multi-)funktionale Materialien %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2005 %J Monday-Morning Lecture, Fortbildungsveranstaltung %T Formgedaechtnismaterialien fuer die Chirurgie %U %X %0 conference lecture %@ %A Lendlein, A. %D 2005 %J HERAEUS Workshop - Medicine Technology %T Polymeric Biomaterials for Long-Term Implantation %U %X %0 conference lecture %@ %A Lendlein, A. %D 2005 %J BMBF-Wettbewerb BioFuture %T Massgeschneiderte, intelligente Polymersysteme fuer den Einsatz in der minimalinvasiven Medizin %U %X %0 conference lecture %@ %A Lendlein, A. %D 2005 %J BCRT-Begutachtung zur Einrichtung eines DFG-Forschungszentrums %T Bio-Engineering technology platform for regenerative therapies %U %X %0 journal article %@ 0920-5063 %A Altankov, G., Albrecht, W., Richau, K., Groth, T., Lendlein, A. %D 2005 %J Journal of Biomaterials Science - Polymer Edition %N 1 %P 23-42 %R doi:10.1163/1568562052843320 %T On the tissue compatibility of poly(ether imide) membranes: An in vitro study on their interaction with human dermal fibroblasts and keratinocytes %U https://doi.org/10.1163/1568562052843320 1 %X Recently we have developed a novel type of membrane based on poly(ether imide) (PEI) which is considered for biomedical application. To improve its physical and biological performance it was modified by blending with poly(benzimidazole) (PBI). In the present study both membranes were characterized in terms of their physicochemical properties and in vitro tissue compatibility using human dermal fibroblasts and keratinocytes. The modified membrane (PEI*) was more hydrophilic, less porous and had an increased surface (zeta) potential. We further found that blending with PBI tends to promote cell contact, at least initially, as indicated by the improved overall cell morphology, adhesion and spreading of fibroblasts, and the development of focal adhesion complexes. The effects of fibronectin (FN) and serum coating were also beneficial when compared to pure PEI and tissue culture polystyrene (TCP), which correlates to a higher adsorption of both FN and vitronectin detected by ELISA. However, a clear tendency for homotypic cellular interaction particularly of keratinocytes was obtained in contact with membranes, which was much stronger pronounced on PEI*. Although the initial adhesion was greater on PEI*, a surprising decrease in cell growth was observed at later stages of incubation, which may be explained with the membrane-promoted cellular aggregation leading to an easier detachment from the substratum. Thus, membranes based on blends of PEI with PBI could provide a tissue compatible scaffold with lowered adhesive properties, which might be a useful tool for the transfer of cells, for example, to in vitro engineered tissue constructs. %0 conference lecture %@ %A Lendlein, A. %D 2005 %J The Medical Device Technology 2005 %T Shape-memory Effects in Polymers Applied to Medical Devices %U %X %0 conference lecture %@ %A Lendlein, A. %D 2005 %J Regenerative Medicine, IZKF Workshop %T Biomaterials in Regenerative Medicine %U %X %0 conference poster %@ %A Lendlein, A. %D 2005 %J BCRT-Begutachtung zur Einrichtung eines DFG-Forschungszentrums %T Bio-Engineering %U %X %0 conference lecture %@ %A Lendlein, A. %D 2005 %J Zukunft der Regenerativen Medizin in der Helmholtz Gemeinschaft, Workshop %T Regenerative Medizin, derzeitige Arbeitsschwerpunkte und Vorschlaege fuer die Konzeption des Programms Regenerative Medizin fuer die zweite Programmperiode %U %X %0 conference lecture %@ %A Lendlein, A. %D 2005 %J 1st Joined German-Japanese Conference on Regenerative Medicine %T Biodegradable Polymers with Shape-memory Effect %U %X %0 conference lecture %@ %A Lendlein, A. %D 2005 %J WING-Konferenz %T (Multi-) funktionale Polymere %U %X %0 conference lecture %@ %A Lendlein, A. %D 2005 %J Biotechnica 2005 %T Regenerative Medizin in der Helmholtz-Gemeinschaft %U %X %0 conference lecture %@ %A Lendlein, A., Kelch, S. %D 2005 %J Euro Nano Forum 2005 %T Multifunctional Polymer Systems Designed for Biomedical Applications %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2005 %J BIOSURF - Tissue-Surface-Interaction %T Stimuli-Sensitive Biomaterial System for Regenerative Medicine %U %X %0 journal article %@ 1386-0291 %A Lendlein, A., Kelch, S. %D 2005 %J Clinical Hemorheology and Microcirculation %N 2 %P 105-116 %T Shape-memory polymers as stimuli-sensitive implant materials %U 2 %X Shape-memory polymers are stimuli-responsive materials. Upon exposure to an external stimulus, e.g. an increase in temperature, they have the capability of changing their shape. The shape-memory effect results from the polymer’s structure and morphology in combination with a certain processing and programming technology. Stimuli-sensitive implant materials have a high potential for applications in minimally invasive surgery. A group of biodegradable implant materials with shape-memory has been developed for applications in biomedicine. These implant materials are not a single polymer but polymer systems that allow the variation of different macroscopic properties over a wide range by only small changes in the chemical structure. In this way, it is possible to implement a variety of different applications with tailor-made polymers of the same family. Two different types of degradable shape-memory polymer systems, covalently cross-linked polymer networks and thermoplastic elastomers, are presented and examples are given for each case. %0 conference lecture %@ %A Lendlein, A. %D 2005 %J Makromolekulare Chemie, GDCh-Fachgruppe %T Multifunktionale Polymersysteme fuer Anwendungen in der Medizin %U %X %0 conference lecture %@ %A Lendlein, A., Hofmann, D. %D 2005 %J E-MRS Spring Meeting %T (Multi-) Funktional Materials %U %X %0 conference lecture %@ %A Lendlein, A. %D 2005 %J Fachverband Biomedizinische Technik, Wuerzburger Medizintechnik Kongress %T (Multi-) Funktionale Materialsysteme fuer Anwendungen in der Medizin %U %X %0 conference lecture (invited) %@ %A Lendlein, A., Kelch, S., Klein, F. %D 2005 %J 5th World Textile Conference AUTEX %T Smart Fibres Based on Shape-memory Polymers %U %X %0 conference lecture %@ %A Lendlein, A. %D 2005 %J 2nd World Congress on Regenerative Medicine %T Polymeric Biomaterials in Regenerative Medicine %U %X %0 conference lecture (invited) %@ %A Ziegler, H.-J., Weidner, S., Malsch, G., Zierke, M., Schroeter, M., Kelch, S., Lendlein, A. %D 2005 %J MALDI-TOF Massenspektrometrie zur Untersuchung von Polymeren, 9. Kolloquium %T Charakterisierung von Endgruppen-modifizierten Oligoetherestern mittels MALDI-TOF %U %X %0 conference lecture (invited) %@ %A Hofmann, D., Lendlein, A. %D 2005 %J German-Japanese Seminar on Regenerative Medicine %T Aktuelle Situation der regenerativen Medizin in Deutschland %U %X %0 journal article %@ 1433-7851 %A Alteheld, A., Feng, Y., Kelch, S., Lendlein, A. %D 2005 %J Angewandte Chemie - International Edition %N 8 %P 1188-1192 %R doi:10.1002/anie.200461360 %T Biodegradable, Amorphous Copolyester-Urethane Networks Having Shape-Memory Properties %U https://doi.org/10.1002/anie.200461360 8 %X No abstract %0 journal article %@ 0376-7388 %A Albrecht, W., Kneifel, K., Weigel, T., Hilke, R., Just, R., Schossig, M., Ebert, K., Lendlein, A. %D 2005 %J Journal of Membrane Science %N 1-2 %P 69-80 %R doi:10.1016/j.memsci.2005.03.042 %T Preparation of highly asymmetric hollow fiber membranes from poly(ether imide) by a modified dry-wet phase inversion technique using a triple spinneret %U https://doi.org/10.1016/j.memsci.2005.03.042 1-2 %X Scanning electron microscopy (SEM) analysis of the morphology of poly(ether imide) (PEI) hollow fiber membranes prepared by a dry–wet spinning technology have been carried out. The results show that the outer layer of the extruded polymer solution can be precipitated by vapor induced phase separation (VIPS) resulting in relatively dense structures. In order to avoid VIPS, a modified air gap spinning process was developed using a triple spinneret where the outer annulus was used for transport of fluids containing a high amount of solvent. As a consequence of the presence of fluid at the outer surface of the nascent hollow fiber, the polymer concentration was locally reduced and the fiber was protected against the sorption of water vapor from the ambient atmosphere in the air gap. The results show that highly asymmetric hollow fiber morphologies without any external skin can be reproducibly prepared. Their separation properties are similar to those of conventionally prepared membranes but the permeability could be improved considerably due to a distinctly reduced support layer resistance. %0 journal article %@ 0376-7388 %A Karimi, M., Albrecht, W., Heuchel, M., Kish, M.H., Frahn, J., Weigel, T., Hofmann, D., Modarress, H., Lendlein, A. %D 2005 %J Journal of Membrane Science %N 1-2 %P 1-12 %R doi:10.1016/j.memsci.2005.04.030 %T Determination of water/polymer interaction parameter for membrane-forming systems by sorption measurement and a fitting technique %U https://doi.org/10.1016/j.memsci.2005.04.030 1-2 %X parameters. For a given polymer, the water/polymer interaction parameters resulting from fits of ternary systems with different solvents agree well. But the obtained values are smaller than the ones resulting from the sorption experiment. The difference is smaller for a more hydrophilic polymer with a higher water uptake than for hydrophobic polymers with a lower uptake. Reasons for this difference will be discussed. %0 journal article %@ 0887-624X %A Lendlein, A., Schmidt, A., Schroeter, M., Langer, R. %D 2005 %J Journal of Polymer Science A %N 7 %P 1369-1381 %R doi:10.1002/pola.20598 %T Shape-memory Polymer Networks from Oligo(e-caprolactone)dimethacrylates %U https://doi.org/10.1002/pola.20598 7 %X Magnetic domain walls in thin films can be well analysed using polarized neutron reflectometry. Well defined streaks in the off-specular spin-flip scattering maps are explained by neutron refraction at perpendicular Néel walls. The position of the streaks depends only on the magnetic induction within the domains, whereas the intensity of the off-specular magnetic scattering depends on the spin-flip probability at the domain walls and on the average size of the magnetic domains. This effect is fundamentally different and has to be clearly distinguished from diffuse scattering originating from the size distribution of magnetic domains. Polarized neutron reflectivity experiments were carried out using a 3He gas spin filter with a analysing power as high as 96% and a neutron transmission of approximately 35%. Furthermore, the off-specular magnetic scattering was enhanced by using neutron resonance and neutron standing wave techniques. %0 conference lecture %@ %A Kelch, S., Malsch, G., Seifert, B., Albrecht, W., Lendlein, A. %D 2005 %J 24. Jahrestagung der Deutschen Gesellschaft fuer Klinische Mikrozirkulation und Haemorheologie %T Cell and Blood Compatibility of Polyacrylnitrile (PAN) and PAN-Copolymers %U %X %0 journal article %@ 0391-3988 %A Seifert, B., Kostadinova, A., Albrecht, W., Groth, T., Altankov, G., Lendlein, A. %D 2005 %J International Journal of Artificial Organs %N 5 %P 511 %T Membranes made of P(AN/AMPS) copolymers for hepatocyte cultivation in bioreactors %U 5 %X Bioartificial liver devices require membranes to support the function and viability of hepatocytes as they are anchor-dependent cells. Membranes currently used in these devices were developed for blood-contacting systems, like hemodialysers or blood oxygenators, and show less than optimal performance in contact with hepatocytes. Tailor-made membranes of acrylonitrile copolymers with acrylamido-methylpropane sulfonic acid (AMPS) were developed for application in a bioartificial liver bioreactor to overcome this bottle-neck. %0 journal article %@ 0391-3988 %A Seifert, B., Zierke, M., Kelch, S., Lendlein, A. %D 2005 %J International Journal of Artificial Organs %N 4 %P 410 %T Blood-contacting Properties of Biodegradable Multi-Block Polymers %U 4 %X Biodegradable polymers are widely used as implant materials, e.g. for surgical suture. Recently, a group of bioresorbable materials with shape-memory (SM) has been developed. SM polymers have the capability to change their shape upon exposure to an external stimulus. In this study we examine the biocompatibility of these polymers to assess them for application in contact with blood cells. %0 conference lecture %@ %A Seifert, B., Kostadinova, A., Albrecht, W., Groth, T., Altankov, G., Lendlein, A. %D 2005 %J Engineering with Membranes 2005 - Medical and biological applications %T Membranes made of P(AN/AMPS) copolymers for hepatocyte cultivation in bioreactors %U %X %0 conference lecture %@ %A Seifert, B., Zierke, M., Kelch, S., Lendlein, A. %D 2005 %J 19th European Conference on Biomaterials %T Evaluation of Biodegradable Multi-Block Polymers in Contact with Endothelium and Blood %U %X %0 conference poster %@ %A Entrialgo-Castano, M., Hofmann, D., Lendlein, A. %D 2005 %J Tag der Chemie 2005 %T Molecular Modeling investigations of dry and first water-swollen states of biodegradable polymers %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2005 %J Vortrag am Institut fuer Werkstoffe - Sonderforschungsbereich 459 %T Formgedaechtnis - Polymere als Beispiel fuer ein multifunktionalisiertes Materialsystem %U %X %0 conference lecture %@ %A Kelch, S., Kratz, K., Seifert, B., Lendlein, A. %D 2005 %J Jahrestagung der deutschen Gesellschaft fuer Chirurgie %T Entwicklung neuer, intelligenter Nahtmaterialien mit Formgedaechtniseffekt fuer die Visceralchirurgie %U %X %0 conference lecture %@ %A Rickert, D., Scheithauer, M., Kelch, S., Franke, R.-P., Lendlein, A. %D 2005 %J Symposium Biomaterialien in der Hals-Nasen-Ohrenheilkunde %T Erste Ergebnisse zum Einsatz eines abbaubaren, elastomeren Polymers zur Mukosarekonstruktion im Tiermodell %U %X %0 journal article %@ 0255-5476 %A Lendlein, A., Kelch, S. %D 2005 %J Materials Science Forum, Functionally Graded Materials VIII %P 219-224 %R doi:10.4028/www.scientific.net/MSF.492-493.219 %T Degradable, Multifunctional Polymeric Biomaterials with Shape-memory %U https://doi.org/10.4028/www.scientific.net/MSF.492-493.219 %X No abstract %0 conference lecture %@ %A Seifert, B., Zierke, M., Kelch, S., Lendlein, A. %D 2005 %J 2nd World Congress on Regenerative Medicine %T Blood-contacting Properties of Biodegradable Multi-Block Polymers %U %X %0 journal article %@ 0168-1656 %A Heilmann, K., Groth, T., Bersing, O., Albrecht, W., Schossig, M., Lendlein, A., Micheel, B. %D 2005 %J Journal of Biotechnology %N 3 %P 291-301 %R doi:10.1016/j.jbiotec.2004.09.004 %T The Influence of Chemical Composition of Cell Culture Material on Growth and Antibody Production of Hybridoma Cells %U https://doi.org/10.1016/j.jbiotec.2004.09.004 3 %X The multiplication and antibody production of murine hybridoma cells cultured on five different polymer membranes were tested and compared with conventional tissue culture polystyrene (TCPS). Membranes were prepared from polyacrylonitrile (PAN) and acrylonitrile copolymerized with N-vinylpyrrolidone (NVP20, NVP30), Na-methallylsulfonat (NaMAS) and N-(3-amino-propyl-methacrylamide-hydrochloride) (APMA). Cell number and antibody concentration were quantified as criteria for viability and productivity. Adhesion of hybridoma cells was characterized by vital and scanning electron microscopy. The results suggest that a strong adhesion of cells, observed on APMA and TCPS, increased cell growth but reduced monoclonal antibody production. In contrast membranes with lowered adhesivity such as NVP20 provided favourable conditions for monoclonal antibody production. In addition it was shown that this membrane possessed also a minor fouling as indicated by the low decrease of water flux across the membrane after protein adsorption. It was concluded that NVP20 could be a suitable material for the development of hollow fibre membranes for bioreactors. %0 conference lecture %@ %A Entrialgo, M., Lendlein, A., Hofmann, D. %D 2005 %J 3rd European Symposium on Biopolymers, ESBP05 %T Molecular Modeling of Hydrolytically Degradable Polyesters %U %X %0 conference lecture %@ %A Feng, Y., Kelch, S., Lendlein, A., Alteheld, A. %D 2005 %J International BIOSURF VI Conference %T Amorphous Biodegradable Shape-Memory Poly(esterurthane) Networks as Stimuli-sensitive Implant Materials %U %X %0 conference lecture %@ %A Luetzow, K., Albrecht, W., Weigel, T., Seifert, B., Groth, T., Lendlein, A. %D 2005 %J Engineering with Membranes 2005: Medical and Biological Applications %T Development of novel poly(ether imide) particles %U %X %0 conference poster %@ %A Luetzow, K., Albrecht, W., Weigel, T., Seifert, B., Groth, T., Lendlein, A. %D 2005 %J Engineering with membranes: Medical and Biological Applications %T Development of Novel Poly(etherimide ) particles for the adsorption of proteins from plasma %U %X %0 journal article %@ 1048-6690 %A Lendlein, A., Kratz, K., Kelch, S. %D 2005 %J Medical Device Technology %N 3 %P 12-14 %T Smart Implant Materials - Capabilities and applications of new biodegradable shape-memory elastomers %U 3 %X Biodegradable polymers are widely used as implant materials e.g. as surgical suture material. A group of biodegradable implant materials with shape-memory has been developed for applications in biomedicine. Biodegradable thermoplastic elastomers, as example for a biodegradable shape-memory polymer system, are presented and a smart suture is given as example for a potential application. The combination of stimuli-sensitive implant materials with techniques of minimally invasive surgery is expected to have high potential for applications. %0 journal article %@ 1386-0291 %A Rickert, D., Lendlein, A., Kelch, S., Moses, M.A., Franke, R.-P. %D 2005 %J Clinical Hemorheology and Microcirculation %N 2 %P 117-128 %T Expression of MMPs and TIMPs in primary epithelial cell cultures of the upper aerodigestive tract seeded on the surface of a novel polymeric biomaterial %U 2 %X Using standard cell biological and biochemical experimental approaches we were able to test the ability of a particular polymer construct to support the adhesion, proliferation, and the cellular acitivity of pharyngeal cells. The delicate balance between Matrix Metalloproteinases (MMPs) and their endogenous inhibitors (Tissue Inhibitor of MMPs, TIMPs) have a decisive function in the remodeling of the extracellular matrix during cellular ingrowth. Novel polymeric biomaterials may be useful to develop new therapeutic options in head and neck surgery. Methods: Primary cell cultures of the pharynx of Sprague-Dawley rats were seeded on the surface of a thermoplastic multi-block copolymer and on a polystyrene surface as control. Conditioned media of the primary cells was analyzed for MMPs and TIMPs. The MMP and TIMP expression was analysed by zymography and a radiometric enzyme assay. Results: No statistically significant differences in the levels of MMP-1, MMP-2, MMP-9 and TIMPs were detected between cells grown on the novel polymer surface versus control. Conclusion: An appropriate understanding of the molecular machinery that regulates gene expression and cellular growth in tissue engineered contructs is the requirement for an optimal adaptation of biodegradable biomaterials to develop new therapeutic options in otolaryngology and head and neck surgery. %0 journal article %@ 0028-0836 %A Lendlein, A., Hongyan, J., Juenger, O., Langer, R. %D 2005 %J Nature %N 7035 %P 879-882 %R doi:10.1038/nature03496 %T Light-induced shape-memory polymers %U https://doi.org/10.1038/nature03496 7035 %X Materials are said to show a shape-memory effect if they can be deformed and fixed into a temporary shape, and recover their original, permanent shape only on exposure to an external stimulus1, 2, 3. Shape-memory polymers have received increasing attention because of their scientific and technological significance4, 5. In principle, a thermally induced shape-memory effect can be activated by an increase in temperature (also obtained by heating on exposure to an electrical current6 or light illumination6, 7). Several papers have described light-induced changes in the shape of polymers8, 9, 10, 11, 12 and gels13, 14, 15, such as contraction8, 9, 10, bending11, 12, 13 or volume changes14, 15. Here we report that polymers containing cinnamic groups can be deformed and fixed into pre-determined shapes—such as (but not exclusively) elongated films and tubes, arches or spirals—by ultraviolet light illumination. These new shapes are stable for long time periods, even when heated to 50 °C, and they can recover their original shape at ambient temperatures when exposed to ultraviolet light of a different wavelength. The ability of polymers to form different pre-determined temporary shapes and subsequently recover their original shape at ambient temperatures by remote light activation could lead to a variety of potential medical and other applications. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2005 %J MRS Fall Meeting 2005 %T Shape-memory effects in polymer networks for medical application %U %X %0 journal article %@ 0013-5585 %A Rickert, D., Lendlein, A., Kelch, S., Franke, R.-P., Moses, M.A. %D 2005 %J Biomedizinische Technik / Biomedical Engineering %N 5 %P 92-99 %T Cell proliferation and cellular activity of primary cell cultures of the oral cavity after cell seeding on thesurface of a degradable, thermoplastic block copolymer %U 5 %X Inhibitors of MMPs, TIMPs) hat eine entscheidende Funktion in Prozessen wie der Wundheilung oder der Zell- und Gewebeintegration von Biomaterialien in das umgebende Gewebe. Kürzlich entwickelte, multifunktionale, abbaubare Formgedächtnispolymere/thermoplastische Blastomere mit Formgedächtniseigenschaften können bei der Entwicklung von neuartigen Therapieoptionen in der Kopf-Halschirurgie eine bedeutende Rolle spielen. Primärzellkulturen der Mundhöhle von Sprague-Dawley Ratten wurden auf der Oberfläche eines abbaubaren, thermoplastischen Blockcopolymers und auf Polystyroloberflächen als Kontrollen ausgesät. Die MMP- und TIMP-Expression wurde mit Hilfe der Zymographie und eines radioaktiven Enzymassays analysiert. Es fanden sich keine statistisch signifikanten Unterschiede der MMP-1-, MMP-2-, MMP-9- und TIMP-Level zwischen den Primärzellkulturen, die auf der Polymeroberfläche und der Kontrolloberfläche gewachsen waren. Weiterreichende Kenntnisse der Mechanismen, die der Gewebeintegration eines Biomaterials nach Implantation im Organismus zugrunde liegen, sind die Voraussetzung für die optimale Adaptation eines Biomaterials an die Bedingungen in vivo, um somit neuartige therapeutische Optionen in der Kopf- und Halschirurgie entwickeln und etablieren zu können. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2005 %J Finanzierung fuer Forschungsgruppen und Gruender - Das BMBF-Programm ExistGo-Bio und der HighTech Gruenderfonds, Informationsveranstaltung %T Gruenden aus einer Forschungseinrichtung - Erfahrungen aus der Praxis %U %X %0 lecture %@ %A Lendlein, A. %D 2005 %J %T Organische Chemie fuer Biologen %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2005 %J Vortrag an der Charite %T Formgedaechtnismaterialien in der Chirurgie %U %X %0 journal article %@ 0044-8249 %A Alteheld, A., Feng, Y., Kelch, S., Lendlein, A. %D 2005 %J Angewandte Chemie %N 8 %P 1212-1216 %R doi:10.1002/ange.200461360 %T Bioabbaubare, amorphe Copolyester-urethannetzwerke mit Formgedaechtniseigenschaften %U https://doi.org/10.1002/ange.200461360 8 %X No abstract %0 conference lecture %@ %A Lendlein, A. %D 2005 %J Symposium, Evangelische Akademie Schloss Tutzing %T Multifunctional Materials for Membranes and Scaffolds %U %X %0 journal article %@ 0024-9297 %A Bertmer, M., Buda, A., Blomenkamp-Hoefges, I., Kelch, S., Lendlein, A. %D 2005 %J Macromolecules %N 9 %P 3793-3799 %R doi:10.1021/ma0501489 %T Biodegradable Shape-Memory Polymer Networks: Characterization with Solid-State NMR %U https://doi.org/10.1021/ma0501489 9 %X Polymer networks made from oligo[(L-lactide-ran-glycolide)]dimethacrylates by UV curing are characterized by solid-state NMR. These polymer networks show a shape-memory effect and could be used as temporary implant materials for medical applications. The 13C spectra enable the direct determination of the cross-link density by a signal at 44 ppm. This is used to correlate its intensity with the chain segment length as well as to study the kinetics of photo-cross-linking. The latter is compared with the gel content, and it is found that the NMR method detects the real amount of covalent cross-links whereas the gel content also depends on influences from constraints such as physical entanglements. The shape-memory effect of the polymer networks can be followed as well by 1H double quantum buildup curves of samples that are programmed by stretching. Results indicate the reversibility of the shape-memory process. %0 conference lecture %@ %A Ziegler, H.-J., Kelch, S., Lendlein, A. %D 2005 %J Projekttreffen: Nano-Pulver als Antennen fuer extern stimulierbare Formgedaechtniscompounds als Nahtmaterial fuer die Medizin %T Synthese und Eigenschaften von bioabbaubaren Formgedaechtnispolymeren %U %X %0 journal article %@ 1022-1360 %A Bertmer, M., Buda, A., Blomenkamp-Hoefges, I., Kelch, S., Lendlein, A. %D 2005 %J Macromolecular Symposia %N 1 %P 110-115 %R doi:10.1002/masy.200551149 %T Solid-State NMR Characterization of Biodegradable Shape-Memory Polymer Networks %U https://doi.org/10.1002/masy.200551149 1 %X Copolymer networks synthesized from dilactide and diglycolide were characterized by solid-state 13C CPMAS NMR in terms of composition, cross-link density, and rate of cross-linking by UV irradiation. The latter is directly evident by a signal at 44 ppm in the 13C NMR spectrum. Comparison of solid-state NMR data with the determination of the gel content revealed that this NMR method is sensitive to the chemical cross-link density whereas the gel content is also influenced by physical constraints such as entanglement. Furthermore, these copolymer networks show a shape-memory effect, i.e. a temporary macroscopic shape can be programmed by heating the network above its glass transition temperature together with fixation during cooling. Reheating without fixation recovers the permanent shape. The recovery of the permanent shape could be followed by 1H DQ NMR buildup curves for a sample that was stretched by 80%. %0 conference lecture (invited) %@ %A Lendlein, A. %D 2005 %J Institutsseminar %T Kunststoffe als Implantatmaterialien Konzepte fuer (Multi-)funktionale Materialien %U %X %0 conference lecture %@ %A Lendlein, A. %D 2005 %J Interventionelle Neuroradiologie, Symposium Charite Campus Benjamin Franklin %T Multifunktionale Biomaterialien %U %X %0 lecture %@ %A Lendlein, A. %D 2005 %J %T Seminar zur Vorlesung Organische Chemie fuer Biologen %U %X %0 conference lecture %@ %A Hofmann, D., Lendlein, A. %D 2005 %J BioJapan %T Multifunctional Biomaterials for Regenerative Medicine %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2005 %J Kongress Innere Medizin %T Intelligente Biomaterialien und deren Anwendungspotential in der Medizin %U %X %0 lecture %@ %A Lendlein, A. %D 2005 %J %T Materialien in den Lebenswissenschaften - Vorlesung fuer Schueler %U %X %0 lecture %@ %A Lendlein, A. %D 2005 %J %T Implants and Prosthetics - Introduction and Definitions %U %X %0 conference poster %@ %A Pimthon, J., Hofmann, D., Willumeit, R., Lendlein, A. %D 2005 %J Biomolecular Simulation 2005 %T Interactions of the Antibacterial Peptide NK-2 with Lipid Bilayers: Molecular Dynamics Simulation Studies %U %X %0 journal article %@ 0940-0079 %A Schroeter, M., Kelch, S., Lendlein, A. %D 2005 %J BIOforum %P 27-29 %T Polymere Shape-Memory Netzwerke in der Medizin %U %X %0 journal article %@ 0391-3988 %A Luetzow, K., Albrecht, W., Weigel, T., Seifert, B., Groth, T., Lendlein, A. %D 2005 %J International Journal of Artificial Organs %N 5 %P 537 %T Development of novel poly (ether imide) particles for the adsorption of proteins from plasma %U 5 %X Aim of this work is the development of novel adsorber particles for extracorporal immunoadsorption which are superior to the existing adsorbers considering porosity, pore size, and compression stability. Poly(ether imide) was chosen as the matrix material because it can be steam sterilized and can be modified covalently with nucleophiles in order to bind the affinity ligands. %0 conference lecture %@ %A Richau, K., Kosmella, H.-J., Ziegler, H.-J., Malsch, G., Kamusewitz, H., Kelch, S., Lendlein, A., Zierke, M., Kratz, K., Jarosz, G., Reiche, J. %D 2005 %J 2nd Max Bergmann Symposium at The Max Bergmann Center of Biomaterials Dresden %T Characterization of the degradation behaviour of bioresorbable shape memory polymers %U %X %0 conference paper %@ %A Richau, K., Kosmella, H.-J., Ziegler, H.-J., Malsch, G., Kamusewitz, H., Kelch, S., Lendlein, A., Zierke, M., Kratz, K., Jarosz, G., Reiche, J. %D 2005 %J Poster-Abstracts, 2nd Max Bergmann Symposium at The Max Bergmann Center of Biomaterials Dresden %P 23 %T Characterization of the degradation behaviour of bioresorbable shape memory polymers %U %X %0 lecture %@ %A Lendlein, A. %D 2005 %J %T Einfuehrung in die Biomaterialien %U %X %0 lecture %@ %A Lendlein, A. %D 2005 %J %T Implants and Prosthetics %U %X %0 conference poster %@ %A Rickert, D., Lendlein, A., Kelch, S., Moses, M., Franke, R.-P. %D 2004 %J Jahrestagung der Deutschen Gesellschaft fuer Biomaterialien %T Biokompatibilitaetstestung von bioabbaubaren Shape Memory Polymeren in vivo %U %X %0 journal article %@ 1616-0177 %A Boese, G., Trimpert, C., Zierke, M., Albrecht, W., Groth, T., Lendlein, A. %D 2004 %J Biomaterialien %N 3 %T Design polymerer Traegerstrukturen zur Wiederherstellung von Dermis und Epidermis %U 3 %X %0 journal article %@ 1616-0177 %A Santoso, F., Schroeter, M., Albrecht, W., Lendlein, A., Schomaecker, R. %D 2004 %J Biomaterialien %N 3 %P 194 %T Simultane Funktionalisierung und Porenoeffnung von Polyetherimid-Membranen zur Entwicklung neuer Traegermaterialien fuer die Apherese %U 3 %X %0 journal article %@ 0044-8249 %A Groth, T., Lendlein, A. %D 2004 %J Angewandte Chemie %N 8 %P 944-948 %R doi:10.1002/ange.200301708 %T In-vivo-Reparatur von Blutgefaessen durch alternierende Adsorption von Polyelektrolyten %U https://doi.org/10.1002/ange.200301708 8 %X %0 journal article %@ 1616-0177 %A Seifert, B., Weckwerth, C., Zierke, M., Kelch, S., Reissfelder, C., Lendlein, A., Buhr, H.-J. %D 2004 %J Biomaterialien %N 3 %T Bioabbaubare polymere Nahtmaterialien im Kontakt zu Gewebezellen und Blut %U 3 %X %0 conference lecture %@ %A Kelch, S., Lendlein, A. %D 2004 %J 23. Jahrestagung der Deutschen Gesellschaft fuer klinische Mikrozirkulation und Haemorheologie %T Shape-Memory Polymers as Stimuli-sensitive Implant Materials %U %X %0 conference lecture %@ %A Seifert, B., Weckwerth, C., Zierke, M., Kelch, S., Reissfelder, C., Lendlein, A., Buhr, H.-J. %D 2004 %J 23. Jahrestagung der Deutschen Gesellschaft fuer Klinische Mikrozirkulation und Haemorheologie %T Biodegradable Multi-Block Polymers in Contact with Blood and Tissue Cells %U %X %0 conference poster %@ %A Feng, Y., Kelch, S., Rickert, D., Fuhrmann, R., Franke, R.-P., Lendlein, A. %D 2004 %J Jahrestagung der Deutschen Gesellschaft fuer Biomaterialien 2004 %T Biokompatible Abbaubare Formgedaechtnispolymersysteme als Intelligente Implantatmaterialien %U %X %0 conference lecture %@ %A Santoso, F., Schroeter, M., Albrecht, W., Lendlein, A., Schomaecker, R. %D 2004 %J Jahrestagung der Deutschen Gesellschaft für Biomaterialien %T Simultane Funktionalisierung und Porenoeffnung von Polyetherimid-Membranen zur Entwicklung neuer Traegermaterialien fuer die Apherese %U %X %0 conference lecture %@ %A Seifert, B., Weckwerth, C., Zierke, M., Kelch, S., Reissfelder, C., Lendlein, A., Buhr, H.-J. %D 2004 %J Jahrestagung der Deutschen Gesellschaft für Biomaterialien 2004 %T Bioabbaubare polymere Nahtmaterialien im Kontakt zu Gewebezellen und Blut %U %X %0 conference poster %@ %A Lendlein, A., Weigel, T., Hilke, R., Albrecht, W., Klein, F., Riedel, M., Marx, U. %D 2004 %J Polydays 2004 %T Porous formed bodies for the cell settlement - produced through melting extrusion %U %X %0 conference lecture %@ %A Lendlein, A. %D 2004 %J Kolloquium des Berliner Polymerverbandes, Aufnahmevortrag %T Intelligente Polymere %U %X %0 conference lecture %@ %A Kelch, S., Seifert, B., Lendlein, A. %D 2004 %J 121. Kongress Deutsche Gesellschaft für Chirurgie %T Entwicklung neuer, intelligenter Nahtmaterialien mit Formgedaechtniseffekt für die Visceralchirurgie %U %X %0 journal article %@ 0344-5690 %A Schulte, J., Kelch, S., Lendlein, A. %D 2004 %J Kultur & Technik %P 21-23 %T Kunststoffe mit Formgedaechtnis - Die erstaunlichen Faehigkeiten intelligenter Materialien %U %X %0 journal article %@ 1433-7851 %A Groth, T., Lendlein, A. %D 2004 %J Angewandte Chemie - International Edition %N 8 %P 926-928 %R doi:10.1002/anie.200301708 %T Layer-by-layer deposition of polyelectrolytes - A versatile tool for the in vivo repair of blood vessels %U https://doi.org/10.1002/anie.200301708 8 %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2004 %J Eingeladener Vortrag an der Technischen Fakultaet der Universitaet Kiel %T Formgedaechtnispolymere %U %X %0 conference lecture %@ %A Kelch, S., Lendlein, A. %D 2004 %J 75. Jahrestagung der Deutschen Gesellschaft für Hals-Nasen-Ohrenheilkunde %T Erste Ergebnisse zum Einsatz eines abbaubaren Formgedaechtnispolymers zur Mukosarekonstruktion im Tiermodell %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2004 %J Regenerative Medizin in der Helmholtz-Gemeinschaft, Ernst-Moritz-Arndt-Universitaet Greifswald, Institut für Pharmakologie %T Implantatmaterialien – Kunststoffe in Pharmazie und Medizin %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2004 %J Forschungsfruehstueck %T Praesentation ueber das Arbeitsgebiet %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2004 %J Adlershofer Analytisches Kolloquium %T Intelligente Polymere %U %X %0 conference lecture %@ %A Boese, G., Zierke, M., Trimpert, C., Albrecht, W., Becker, M., Schossig, M., Groth, T., Lendlein, A. %D 2004 %J Strategies in Tissue Engineering, International Conference %T Design of polymer scaffolds to support dermal and epidermal reconstruction %U %X %0 conference lecture %@ %A Boese, G., Trimpert, C., Zierke, M., Albrecht, W., Groth, T., Lendlein, A. %D 2004 %J Jahrestagung der Deutschen Gesellschaft fuer Biomaterialien %T Design polymerer Traegerstrukturen zur Wiederherstellung von Dermis und Epidermis %U %X %0 conference lecture %@ %A Seifert, B., Weckwerth, C., Zierke, M., Kelch, S., Lendlein, A., Isbert, C., Buhr, H.-J. %D 2004 %J Strategies in Tissue Engineering, Internationale Konferenz %T Biodegradable shape-memory polymers as implant materials %U %X %0 conference poster %@ %A Kelch, S., Alteheld, A., Feng, Y., Lendlein, A. %D 2004 %J Rolduc Polymer Meeting 2004 %T Amorphous, biodegradable Poly(esterurethane) Networks with Shape-Memory %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2004 %J Kunststoffe in der Medizintechnik, VDI-K-Fachtagung %T Shape Memory Polymere - Grundlagen der Technologie und Potential für biomedizinsche Anwendungen %U %X %0 conference lecture %@ %A Kelch, S., Feng, Y., Lendlein, A. %D 2004 %J Polydays 2004 %T Amorphous, Biodegradable Polymer Networks with Shape-Memory %U %X %0 conference poster %@ %A Seifert, B., Weckwerth, C., Zierke, M., Kelch, S., Reissfelder, C., Lendlein, A., Buhr, J. %D 2004 %J Polydays 2004 %T Evaluation of biodegradable shape-memory polymers as implant materials %U %X %0 conference lecture %@ %A Entrialgo-Castano, M., Hofmann, D., Lendlein, A. %D 2004 %J Polydays 2004 %T Atomistic Bulk Models for Polyglycolide and Poly(L-lactide) %U %X %0 conference lecture %@ %A Lendlein, A. %D 2004 %J Workshop on Health Science, Helmholtz-Dead Sea-Projekt %T Regenerative Medicine %U %X %0 conference poster %@ %A Luetzow, K., Albrecht, W., Weigel, T., Lendlein, A. %D 2004 %J Jahrestagung der Deutschen Gesellschaft fuer Biomaterialien %T Entwicklung einer neuartigen polymeren Traegermatrix fuer die Immunadsorption %U %X %0 conference lecture %@ %A Lendlein, A., Kelch, S. %D 2004 %J 8th International Symposium on Multifunctional and Functionally Graded Materials, FGM 2004 %T Degradable, Multifunctional Polymeric Biomaterials with Shape-memory %U %X %0 journal article %@ 1465-3249 %A Seifert, B., Weckwerth, C., Zierke, M., Kelch, S., Lendlein, A., Isbert, C., Buhr, H.-J. %D 2004 %J Cytotherapy %N 3 %P 257 %T Biodegradable shape-memory polymers as implant materials %U 3 %X One problem in suturing is that the suture becomes loose after swelling of tissue went down. Sutures made of SM polymers could provide a subsequent tightening of suture initiated by an external thermal stimulus. Also for knot formation in minimally invasive surgery these polymers are promising materials. In this study we examined the biocompatibility of biodegradable polymers with and without SM effect to assess them for application in contact with endothelium. %0 conference lecture %@ %A Lendlein, A., Franke, R.-P. %D 2004 %J Medizintechnik, Expertengespraech %T Regenerative Therapien %U %X %0 conference lecture %@ %A Lendlein, A. %D 2004 %J 121. Chirurgenkongress %T Innovationen im biotechnischen/biomedizinischen Bereich und deren Auswirkungen auf die Chirurgie %U %X %0 book %@ %A Emmrich, F., Lendlein, A. %D 2004 %J %T Perspektiven für die Regenerative Medizin in Deutschland - Langfassung %U %X %0 conference poster %@ %A Lendlein, A., Klein, F. %D 2004 %J Chemische Nanotechnologie Partnering-Event %T Systemvergleich unterschiedlicher Verfahren zur Herstellung poroeser Formkoerper aus Kunststoffen %U %X %0 conference poster %@ %A Lendlein, A., Schroeter, M. %D 2004 %J BMBF-Wettbewerb BioFuture %T Massgeschneiderte, intelligente Polymersysteme fuer den Einsatz in der minimalinvasiven Medizin %U %X %0 conference lecture %@ %A Lendlein, A. %D 2004 %J Vorstellung der wissenschaftlichen Arbeiten der GKSS %T Biomaterialentwicklung bei GKSS %U %X %0 conference lecture %@ %A Lendlein, A., Kelch, S. %D 2004 %J New Technologies and Smart Textiles for Industry and Fashion %T Smart Fibres and Textiles based on Shape-memory Polymers %U %X %0 conference lecture %@ %A Lendlein, A. %D 2004 %J Regenerative Therapien, Initiative Berlin %T Regenerative Medizin in Berlin-Brandenburg - ein bundesweiter Vergleich %U %X %0 conference lecture %@ %A Lendlein, A. %D 2004 %J Strategiekonferenz DFG-Forschungszentrum %T Polymeric Biomaterials in Regenerative Medicine %U %X %0 conference lecture %@ %A Lendlein, A. %D 2004 %J Smart Coatings III, Conference %T Shape-Memory Polymers as Stimuli-Sensitive Materials %U %X %0 conference lecture %@ %A Lendlein, A., Kelch, S. %D 2004 %J Shape Memory and Superlastic Technologies %T Tailor-made Shape-memory Polymer Networks %U %X %0 conference lecture %@ %A Lendlein, A. %D 2004 %J Funktionale Polymere, SKZ Fachtagung %T Formgedaechtnispolymere %U %X %0 conference lecture %@ %A Hofmann, D., Lendlein, A. %D 2004 %J Bio Con Valley - Life Science for the future 2004 %T Biomaterialien in der Regenerativen Medizin %U %X %0 conference lecture %@ %A Lendlein, A. %D 2004 %J GDCh-Veranstaltung des Ortsverbandes Bayreuth %T Formgedaechtniseigenschaften von Polymernetzwerken mit Oligo (e-caprolacton)-Schaltsegmenten %U %X %0 conference lecture %@ %A Lendlein, A. %D 2004 %J Gesundheit - Wirtschaft - Innovation NRW, Forum 3 %T Spitzenmedizin in NRW %U %X %0 journal article %@ 1386-0291 %A Binzen, E., Lendlein, A., Kelch, S., Rickert, D., Franke, R.-P. %D 2004 %J Clinical Hemorheology and Microcirculation %N 3-4 %P 283-288 %T Biomaterial-microvasculature interaction on polymers after implantation in mice %U 3-4 %X Biomaterial research is expected to forward new materials to be used as, e.g., implant materials or as scaffolds for tissue engineering. It is central for such a scaffold material to create the track on which those cells can inhabitate the scaffold needed to rebuild functional tissue substitutes. For the biointegration of the implant with the native cellular tissue this must be able to grow on the material surface. For the elimination of the degradation products and the adeqaute transport of nutrients/gases within the newly formed tissue the angiogenesis of new blood vessels is thought to play an important role. %0 lecture %@ %A Lendlein, A. %D 2004 %J %T Seminar zur Vorlesung Organische Chemie fuer Biologen %U %X %0 lecture %@ %A Lendlein, A. %D 2004 %J %T Introduction to Biomaterial Science - New developments in biomimetic materials %U %X %0 journal article %@ 1616-0177 %A Luetzow, K., Albrecht, W., Weigel, T., Lendlein, A. %D 2004 %J Biomaterialien %N 3 %P 177 %T Entwicklung einer neuartigen polymeren Traegermatrix fuer die Immunadsorption %U 3 %X Extrakorporale Immunadsorption ist eine im klinischen Bereich etablierte Methode zur Behandlung von Krankheiten, bei denen pathogene Substanzen wie beispielsweise Autoantikörper oder Toxine durch Affinitätschromatographie entfernt werden. Die existierenden Adsorber haben zwei wesentliche Nachteile: sie sind entweder nicht wärmesterilisierbar und müssen somit aseptisch produziert werden oder sie haben eine niedrige Bindungsspezifität bezüglich der Antikörper. Um effektive und gleichzeitig kostengünstigere Immunadsorptionsverfahren anbieten zu können, müssen neue Adsorber, d.h. neuartige Trägermaterialien und Affinitätsliganden, entwickelt werden. In diesem Beitrag stellen wir die Entwicklung einer neuen Trägermatrix vor. %0 journal article %@ 1616-0177 %A Rickert, D., Lendlein, A., Kelch, S., Moses, M.A., Franke, R.-P. %D 2004 %J Biomaterialien %N 3 %P 193 %T Biokompatibilitaetstestung von bioabbaubaren Shape Memory Polymeren in vivo %U 3 %X %0 journal article %@ 1616-0177 %A Feng, Y., Kelch, S., Rickert, D., Fuhrmann, R., Franke, R.-P., Lendlein, A. %D 2004 %J Biomaterialien %N 3 %P 159 %T Biokompatible Abbaubare Formgedaechtnispolymersysteme als Intelligente Implantatmaterialien %U 3 %X %0 lecture %@ %A Lendlein, A. %D 2004 %J %T Einfuehrung in die Biomaterialien %U %X %0 conference lecture %@ %A Kelch, S., Lendlein, A. %D 2004 %J ASAIO´s 50th Anniversary Conference %T Biodegradable scaffolding for tissue structuring %U %X %0 conference lecture %@ %A Lendlein, A., Kelch, S. %D 2004 %J Rolduc Polymer Meeting %T Biodegradable Polymer Networks with Shape-Memory %U %X %0 lecture %@ %A Lendlein, A. %D 2004 %J %T Organische Chemie fuer Biologen %U %X %0 conference lecture %@ %A Lendlein, A., Kelch, S. %D 2003 %J Ostsee Venentage %T Shape-Memory Polymers as Stimuli-sensitive Implant Materials %U %X %0 conference poster %@ %A Lendlein, A., Kelch, S. %D 2003 %J 18th European Conference on Biomaterials %T Biocompatibility Testing of Biodegradable Shape-Memory Polymers in Vivo %U %X %0 conference poster %@ %A Buchlow, T., Santoso, F., Schroeter, M., Albrecht, W., Hofmann, D., Wuellen, C.van, Lendlein, A. %D 2003 %J Tag der Chemie %T Polyetherimid-Oeffnung durch Amine: Experiment und Simulation %U %X %0 journal article %@ 1386-0291 %A Rickert, D., Lendlein, A., Kelch, S., Peters, I., Moses, M.A., Franke, R.-P. %D 2003 %J Clinical Hemorheology and Microcirculation %N 3 %P 175-181 %T The importance of angiogenesis in the interaction between polymeric biomaterials and surrounding tissue %U 3 %X %0 journal article %@ 0323-3243 %A Kelch, S., Lendlein, A., Muellen, A., Ridder, U. %D 2003 %J Technische Textilien / Technical Textiles %N 4 %P E 159-E160 %T Textile polymer Scaffolds for das tissue engineering %U 4 %X %0 conference poster %@ %A Lendlein, A., Kelch, S. %D 2003 %J Gemeinsame Jahrestagung der Oesterreichischen, Deutschen und Schweizerischen Gesellschaft für Biomedizinische Technik %T In vivo Biokompatibilitaet von Formgedaechtnispolymeren fuer die Anwendung als stimuli-sensitive Implantatmaterialien %U %X %0 conference lecture %@ %A Seifert, B., Groth, T., Luetzow, K., Albrecht, W., Lendlein, A. %D 2003 %J Ostsee Venentage %T Charakterisierung der Biokompatibilität neuartiger Partikel für die therapeutische Apherese %U %X %0 conference poster %@ %A Schwarze, M., Schroeter, M., Albrecht, W., Lendlein, A. %D 2003 %J Tag der Chemie %T Untersuchungen an Polyetherimidmembranen fuer den Einsatz als Adsorbermatrix %U %X %0 conference lecture (invited) %@ %A Lendlein, A., Kelch, S. %D 2003 %J Rolduc Polymer Meeting 2003 %T Tailor-made, Degradable Polymers for Biomedical Applications %U %X %0 conference lecture (invited) %@ %A Lendlein, A., Kelch, S. %D 2003 %J New Biomedical Materials Conference 2003 %T Biodegradable, Elastic Shape-Memory Polymers for Potential Biomedical Applications %U %X %0 conference poster %@ %A Lendlein, A., Kelch, S. %D 2003 %J 18th European Conference on Biomaterials %T Shape-Memory Polymers as Stimuli-sensitive Implant Materials %U %X %0 conference lecture %@ %A Lendlein, A. %D 2003 %J Fruehstueck mit Bundestagsabgeordneten %T Regenerative Medizin -Vorstellung der Aktivitaeten im HGF-Vorprogramm %U %X %0 conference poster %@ %A Albrecht, W., Boese, G., Groth, T., Luetzow, K., Lendlein, A. %D 2003 %J Medica 2003 %T Beitraege zur Regenerativen Medizin %U %X %0 conference poster %@ %A Lendlein, A. %D 2003 %J 5. BMBF-Biotechnologietage - BMBF-Wettbewerb BIOFUTURE %T Massgeschneiderte, intelligente Polymersysteme fuer den Einsatz in der minimalinvasiven Medizin %U %X %0 journal article %@ 0021-9304 %A Rickert, D., Lendlein, A., Schmidt, A.M., Kelch, S., Roehlke, W., Fuhrmann, R., Franke, R.-P. %D 2003 %J Journal of Biomedical Materials Research B %N 2 %P 722-731 %T In Vitro Cytotoxicity Testing of AB-Polymer Networks Based on Oligo(e-caprolactone) Segments After Different Sterilization Techniques %U 2 %X %0 conference lecture %@ %A Lendlein, A. %D 2003 %J 1st World Congress on Regenerative Medicine %T Regenerative Medicine - Introduction to a Research Program of the Helmholtz Association (HGF) %U %X %0 conference lecture %@ %A Lendlein, A. %D 2003 %J Wundverschluss und Nahttechniken - Bauchwand- und Gastrointestinaltrakt, Workshop, Klinikum rechts der Isar %T Der selbstknotende Faden - Neue Entwicklungen %U %X %0 lecture %@ %A Lendlein, A. %D 2003 %J %T Einfuehrung in die Biomaterialien %U %X %0 lecture %@ %A Lendlein, A. %D 2003 %J %T Antrittsvorlesung (Selbst-)heilende Kunststoffe %U %X %0 lecture %@ %A Lendlein, A. %D 2003 %J %T Organische Chemie für Biologen %U %X %0 conference lecture (invited) %@ %A Lendlein, A. %D 2003 %J Biologischer Organersatz - Wissenschaftlicher Ausschuss des Gesundheitsforschungsrates %T Regenerative Medizin %U %X %0 conference lecture %@ %A Lendlein, A. %D 2003 %J Sonntagsvorlesung, Altes Rathaus %T Implantatmaterialien – Kunststoffe in Pharmazie und Medizin %U %X %0 conference lecture %@ %A Lendlein, A. %D 2003 %J ESAO - Congress %T Polymeric Biomaterials in Regenerative Medicine %U %X %0 journal article %@ 1433-7851 %A Lendlein, A., Kelch, S. %D 2002 %J Angewandte Chemie - International Edition %N 12 %P 2034-2057 %R doi:10.1002/1521-3773(20020617)41:12%3C2034::AID-ANIE2034%3E3.0.CO;2-M %T Shape-Memory Polymer %U https://doi.org/10.1002/1521-3773(20020617)41:12%3C2034::AID-ANIE2034%3E3.0.CO;2-M 12 %X Material scientists predict a prominent role in the future for self‐repairing and intelligent materials. Throughout the last few years, this concept has found growing interest as a result of the rise of a new class of polymers. These so‐called shape‐memory polymers by far surpass well‐known metallic shape‐memory alloys in their shape‐memory properties. As a consequence of the relatively easy manufacture and programming of shape‐memory polymers, these materials represent a cheap and efficient alternative to well‐established shape‐memory alloys. In shape‐memory polymers, the consequences of an intended or accidental deformation caused by an external force can be ironed out by heating the material above a defined transition temperature. This effect can be achieved because of the given flexibility of the polymer chains. When the importance of polymeric materials in our daily life is taken into consideration, we find a very broad, additional spectrum of possible applications for intelligent polymers that covers an area from minimally invasive surgery, through high‐performance textiles, up to self‐repairing plastic components in every kind of transportation vehicles. %0 journal article %@ 0044-8249 %A Lendlein, A., Kelch, S. %D 2002 %J Angewandte Chemie %N 12 %P 2138-2162 %T Formgedaechtnispolymere %U 12 %X %0 journal article %@ 0013-5585 %A Rickert, D., Lendlein, A., Kelch, S., Fuhrmann, R., Franke, R.-P. %D 2002 %J Biomedizinische Technik / Biomedical Engineering %N 11 %P 285-289 %T Detailed evaluation of the agarose diffusion test in biocompatibility study with a microscopic image analysis system. Effect of plasma sterilization on biocompatible of an improved photoset polymer %U 11 %X %0 conference lecture %@ %A Lendlein, A., Kelch, S. %D 2002 %J Jahrestagung der Deutschen Gesellschaft fuer Klinische Mikrozirkulation und Haemorheologie %T Shape-Memory Polymers as Stimuli-sensitive Implant Materials %U