Biomacromolecules, Vol.10, No.7, 1795-1803, 2009
Cell-Adhesive Star Polymers Prepared by ATRP
This study presents the synthesis and evaluation of cell adhesive poly(ethylene oxide) (PEO) star polymers for potential biomedical applications. Star polymers with a size of approximately 20 nm and with relatively low polydispersities (M-w/M-n <= 1.6), containing GRGDS (Gly-Arg-Gly-Asp-Ser) segments, were prepared by atom transfer radical copolymerization of PEO methyl ether methacrylate macromonomer (MM), telechelic GRGDS-PEO-acrylate MM, and ethylene glycol dimethacrylate (EGDMA). Results from H-1 NMR spectroscopy confirmed the covalent incorporation of the peptide into the star periphery. In vitro cytotoxicity experiments showed star polymers to be cytocompatible (>= 95% cell viability) and GRGDS-star hybrid hydrogels supported the attachment of MC3T3,E1 (subclone 4) cells. Hybrid hydrogels were prepared by free radical photopolymerization based on 10% (wt/v) PEO dimethacrylates M-n = 4000 g/mol with 1% (wt/v) GRGDS-star polymers having different peptide content. Cell adhesiveness was also determined from thin film coatings prepared with GRGDS-containing star polymers oil nonadherent plastic plates. After 24 h incubation, phase contrast microscopy and scanning electron microscopy (SEM) images showed uniform cell adhesion and distribution over the film containing cell-adhesive star polymers. These results confirm that incorporation of RGD ligand-binding motifs into PEO-based star polymers is required to influence substrate-cell interactions.