Bioactive Antifouling Surfaces by Visible-Light-Triggered Polymerization

Hierarchical bioactive surfaces are created by visible-light-induced surface-initiated living radical polymerization employing tris[2-phenylpyridinato-C2,N]iridium(III) as a photocatalyst. The hierarchical antifouling diblock copolymer structures consist of N-(2-hydroxypropyl)-methacrylamide (first block) and carboxybetaine methacrylate (second block). The living nature of the polymerization is shown by a linear increase in layer thickness (as measured by atomic force microscopy) and reinitiation of the polymerization to create a patterned second block of polymer. The chemical structure of the brushes is confirmed by X-ray photoelectron spectroscopy and attenuated total reflection Fourier transform infrared spectroscopy measurements. The block copolymer brushes demonstrate excellent antifouling properties when exposed to single-protein solutions or to bovine serum. The second carboxybetaine block of the hierarchical antifouling structures can effectively be biofunctionalized with an anti-fibrinogen antibody. The coated surfaces show a high affinity and specificity to fibrinogen, while preventing nonspecific adsorption from other proteins in bovine serum.