Bioactive MAO/CS composite coatings on Mg-Zn-Ca alloy for orthopedic applications

Abstract MAO/CS composite coatings were generated on Mg-1.75Zn-0.56Ca alloy surface for protection and improving biocompatibility of Mg-Zn-Ca alloy in the physiological environment. The microstructure, surface analysis and corrosion resistance of samples were evaluated by scanning electronic microcopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in SBF solution. In addition, in vitro cell cytotoxicity test was performed by MTT tests. The findings of this work indicated that MAO/CS composite coatings were smooth and defect-free. The MAO/CS coatings retained a low degradation rate and the solution pH value at a moderate level (≤7.5) during immersion test. The corrosion resistance and cell proliferation were greatly enhanced by the composite coating. Furthermore, the different cell cytotoxicity on Mg alloy, MAO and MAO/CS coating was discussed.