Photochemical grafting of fluorinate alkenes on DLC coated Ti6Al4V to improve in vitro cytocompatibility, friction and corrosion resistance

Ti6Al4V substrates were multiply modified to create a surface with improved biocompatibility and functional properties. The multi-modifications of Ti6Al4V alloy involve depositing diamond-like carbon (DLC) on it as a bio-mechanical coating and then grafting 1H,1H,2H,2H-perfluorodecyl acrylate on DLC from neat liquids upon irradiation at 254 nm to form a dense monolayer. The as-fabricated multilayer films were characterized using X-ray photoelectron spectroscopy (XPS), contact angle meter (CA), and 3D surface profiler. Results show that the bifunctional alkenes are successfully photochemically grafted to DLC-coated Ti6Al4V and the multi-modifications evidently reduce both the surface energy and roughness. By in vitro cytotoxicity test with MC3T3-E1 osteoblasts, the as-fabricated films exhibit admirable cytocompatibility. The longtime soaked films also display the behavior for excellent anticorrosion and friction in the simulated body fluid (SBF) environment. All results suggest that the biocompatibility and functional properties of the multiply modified Ti6Al4V substrates have been continuously adapted to a desired value. Owing to the DLC which can be deposited on most substrate materials and the probable application extension of photochemical grafting to wide range, we envisage that this method will provide a potential and effective approach for the surface modification of DLC coated and other implant biomaterials.