Bio-functionalization of micro-arc oxidized magnesium alloys via thiol-ene photochemistry.

To enhance corrosion resistance and hemocompatibility of magnesium alloy (Mg alloy), poly(ethylene glycol) methacrylate (PEGMA) was covalently bonded to micro-arc oxidation treated Mg alloy substrate via thiol-ene photochemistry using self-assembled (3-mercaptopropyl)trimethoxysilane film as spacer. Chemical composition of the modified surfaces was verified by attenuated total reflection Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy analysis and X-ray diffraction. Scanning electronic microscopy was used to show morphologies of the samples at different stages. Results of water contact angle measurement showed that the hydrophilicity of the surface has improved significantly after surface modification. Potentiodynamic polarization, electrochemical impedance spectroscopy and hydrogen evolution test demonstrated that corrosion resistance increased significantly for modified Mg alloy versus unmodified surfaces. In the meantime, the surface bonding of PEGMA imparted anti-platelet adhesion compared to the Mg alloy surface, displaying excellent hemocompatibility. This composite coating technique gives promise in acutely reducing both the corrosion and platelet adhesion, making it attractive for application to blood contacting material, such as vascular stents, made from degradable Mg alloys. [ABSTRACT FROM AUTHOR]