Preparation, evaluation and functionalization of biomimetic block copolymer coatings for potential applications in cardiovascular implants

Abstract

Effective prevention of the formation of blood coagulation is crucial in blood contact devices. Moreover, the specific service environment also requires specialized function. In this study, triblock copolymers containing zwitterionic units of phosphorylcholine (PC) and nonionic units of trimethoxysilyl (TMS) were synthesized via atom transfer radical polymerization (ATRP). In addition, random copolymers containing 2-methacryloyloxyethyl phosphorylcholine (MPC) and 3-(Trimethoxysilyl)propyl methacrylate (TMSPMA) were synthesized via conventional free radical polymerization. Further, the polymers were immobilized on biomedical metal sheets to construct biomimetic antifouling coatings via covalent fixation. Experiments, including contact angle (WCA) measurements, platelet adhesion, and fibrinogen denaturation, show that one of the triblock copolymers, MePBMTM III sample, exhibited the best hemocompatibility and labeled as MePBMTM in the follow-up evaluations. Finally, vascular endothelial growth factor (VEGF) was introduced on the MePBMTM coating via covalent fixation. The results of X-ray photoelectron spectroscopy (XPS) and quartz crystal microbalance (QCM) confirmed the successful fabrication of VEGF/triblock phospholipid polymers coating. In vitro smooth muscle cells (SMCs) cultures revealed that the VEGF/triblock phospholipid polymers coating significantly inhibited the attachment and proliferation of SMCs. In vitro endothelial cells (ECs) and endothelial progenitor cells (EPCs) cultures further confirmed that the VEGF/triblock phospholipid polymers coating effectively promoted their adhesion and proliferation.