Surface modification of SPEU films by ozone induced graft copolymerization to improve hemocompatibility

Abstract

Surface modification of segmented poly(ether urethane) (SPEU) by graft copolymerization with N, N′-dimethyl- N-methacryloyloxyethyl- N-(3-sulfopropyl) ammonium (DMMSA), a zwitterionic sulfobetaine structure, was conducted. A simple two-step procedure for grafting of DMMSA onto the surface of SPEU film was used. The surface was first treated with ozone to introduce active hydroperoxide groups. The active surface was then exposed to the DMMSA solution in the sealed tube. Grafted SPEU film was characterized by ATR–FTIR, XPS and contact angle measurement. ATR–FTIR and XPS investigations confirmed the graft copolymerization. The monomer concentration, copolymerization temperature and time were varied to maximize the efficiency of DMMSA grafting. The equilibrium water content (EWC) and contact angle measurements showed that the hydrophilicity of the film had been greatly improved. The blood compatibility of the grafted films was evaluated by platelet adhesion in platelet rich plasma (PRP), deposits in blood control and protein adsorption in bovine fibrinogen using SPEU film as the control. No platelet adhesion and no thrombus were observed for the grafted films incubated in PRP for 300 min and in blood for 120 min, respectively. The protein adsorption was reduced on the grafted films after incubation in bovine fibrinogen for 120 min. These results proved that improved blood compatibility was obtained by grafting this new zwitterionic sulfobetaine structure monomer onto SPEU film.