Fabrication of robust biomimetic coating by integrated physisorption/chemical crosslinking technique

Abstract

Intrinsic hydrophobicity of polymeric biomedical devices generally causes adverse complications (i.e. thrombosis formation). In this study, biomimetic surface modification is conducted on different hydrophobic substrates (PP, PET and PTFE) by physisorption and subsequent UV induced chemical crosslinking of a ternary methacrylate copolymer bearing phosphorylcholine (PC), cholesteryl (Chol) and azidophenyl (Az) side groups, poly(MPC-co-CMA-co-AzMA) (PMCA). X-ray photoelectron spectrophotometer (XPS), atomic force microscopy (AFM) and water contact angle (WCA) measurements are used to monitor the changes in chemical composition, morphology and wetting behavior of the polymeric substrate surfaces before and after surface modification. The protein adsorption and platelet adhesion experiments are also performed to assess its antifouling properties. The results show that the synergistic contribution of physical anchor of Chol groups and chemical crosslinking of Az moieties leads to the formation of a highly crosslinked cell outer membrane mimetic coating with relatively uniform and dense nano-granular surface textures. The resultant PMCA modified surface exhibits greatly enhanced hydrophilicity due to the enrichment of hydrophilic phosphorylcholine moieties on the outer layer of PMCA coating. Particularly, compared with poly(MPC-co-CMA) (PMC) and poly(MPC-co-AzMA) (PMA) coatings, PMCA coating possesses good surface stability and interfacial adhesion performance. It provides the polymeric substrates with significantly improved antifouling property. The amounts of proteins and platelets adsorbed or adhered on PMCA modified surfaces could be reduced by at least 85% and 97% after incubation for 48 h, respectively. It offers a facile way to fabricate robust antifouling surface for the improvement of the biocompatibility of polymeric biomedical devices.