Filters

2020 - 20213

More filters

20213
Reset filters

Settings

search.filters.applied.f.access: openAccess × Author: Freudenberg, Uwe × DDC: 540 × Type: Text × Publisher: Weinheim : Wiley-VCH × WGL Institute: IPF ×

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Poly(2-alkyl-2-oxazoline)-Heparin Hydrogels—Expanding the Physicochemical Parameter Space of Biohybrid Materials
    (Weinheim : Wiley-VCH, 2021) Hahn, Dominik; Sonntag, Jannick M.; Lück, Steffen; Maitz, Manfred F.; Freudenberg, Uwe; Jordan, Rainer; Werner, Carsten
    Poly(ethylene glycol) (PEG)-glycosaminoglycan (GAG) hydrogel networks are established as very versatile biomaterials. Herein, the synthetic gel component of the biohybrid materials is systematically varied by combining different poly(2-alkyl-2-oxazolines) (POx) with heparin applying a Michael-type addition crosslinking scheme: POx of gradated hydrophilicity and temperature-responsiveness provides polymer networks of distinctly different stiffness and swelling. Adjusting the mechanical properties and the GAG concentration of the gels to similar values allows for modulating the release of GAG-binding growth factors (VEGF165 and PDGF-BB) by the choice of the POx and its temperature-dependent conformation. Adsorption of fibronectin, growth of fibroblasts, and bacterial adhesion scale with the hydrophobicity of the gel-incorporated POx. In vitro hemocompatibility tests with freshly drawn human whole blood show advantages of POx-based gels compared to the PEG-based reference materials. Biohybrid POx hydrogels can therefore enable biomedical technologies requiring GAG-based materials with customized and switchable physicochemical characteristics. © 2021 The Authors. Advanced Healthcare Materials published by Wiley-VCH GmbH.
  • Thumbnail Image
    Item
    Amphiphilic Copolymers for Versatile, Facile, and In Situ Tunable Surface Biofunctionalization
    (Weinheim : Wiley-VCH, 2021) Ruland, André; Schenker, Saskia; Schirmer, Lucas; Friedrichs, Jens; Meinhardt, Andrea; Schwartz, Véronique B.; Kaiser, Nadine; Konradi, Rupert; MacDonald, William; Helmecke, Tina; Sikosana, Melissa K.L.N.; Valtin, Juliane; Hahn, Dominik; Renner, Lars D.; Werner, Carsten; Freudenberg, Uwe
    Precision surface engineering is key to advanced biomaterials. A new platform of PEGylated styrene-maleic acid copolymers for adsorptive surface biofunctionalization is reported. Balanced amphiphilicity renders the copolymers water-soluble but strongly affine for surfaces. Fine-tuning of their molecular architecture provides control over adsorptive anchorage onto specific materials-which is why they are referred to as "anchor polymers" (APs)-and over structural characteristics of the adsorbed layers. Conjugatable with an array of bioactives-including cytokine-complexing glycosaminoglycans, cell-adhesion-mediating peptides and antimicrobials-APs can be applied to customize materials for demanding biotechnologies in uniquely versatile, simple, and robust ways. Moreover, homo- and heterodisplacement of adsorbed APs provide unprecedented means of in situ alteration and renewal of the functionalized surfaces. The related options are exemplified with proof-of-concept experiments of controlled bacterial adhesion, human umbilical vein endothelial cell, and induced pluripotent cell growth on AP-functionalized surfaces.
  • Thumbnail Image
    Item
    Tuning the Local Availability of VEGF within Glycosaminoglycan-Based Hydrogels to Modulate Vascular Endothelial Cell Morphogenesis
    (Weinheim : Wiley-VCH, 2020) Limasale, Yanuar Dwi Putra; Atallah, Passant; Werner, Carsten; Freudenberg, Uwe; Zimmermann, Ralf
    Incorporation of sulfated glycosaminoglycans (GAGs) into cell-instructive polymer networks is shown to be instrumental in controlling the diffusivity and activity of growth factors. However, a subtle balance between local retention and release of the factors is needed to effectively direct cell fate decisions. To quantitatively unravel material characteristics governing these key features, the GAG content and the GAG sulfation pattern of star-shaped poly(ethylene glycol) (starPEG)–GAG hydrogels are herein tuned to control the local availability and bioactivity of GAG-affine vascular endothelial growth factor (VEGF165). Hydrogels containing varying concentrations of heparin or heparin derivatives with different sulfation pattern are prepared and thoroughly characterized for swelling, mechanical properties, and growth factor transport. Mathematical models are developed to predict the local concentration and spatial distribution of free and bound VEGF165 within the gel matrices. The results of simulation and experimental studies concordantly reveal how the GAG concentration and sulfation pattern determine the local availability of VEGF165 within the cell-instructive hydrogels and how the factor—in interplay with cell-instructive gel properties—determines the formation and spatial organization of capillary networks of embedded human vascular endothelial cells. Taken together, this study exemplifies how mathematical modeling and rational hydrogel design can be combined to pave the way for precision tissue engineering. © 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim