Preparation and characterization of micro-arc oxidation biological coatings on magnesium alloys containing graphene oxide

Magnesium (Mg) alloys have been widely investigated as a biodegradable metallic biomaterial. However, the rapid corrosion rate seriously limits their clinical application. The corrosion resistance and biocompatibility of Mg alloys can be improved by micro-arc oxidation (MAO) technology, and can be further improved by introducing graphene oxide (GO). The loading of GO provides a better support structure for in-situ nucleation and growth of MAO coating, and enhances the cell viability through nano effect and reactive oxygen species. The layered microporous structure of GO coating provides a suitable micro-environment for the adhesion and proliferation of osteoblasts. The structures and elements are analyzed by XRD, FT-IR, XPS, Raman spectroscopy, SEM and EDS, as well as adhesion strength and HEV are tested. EIS and immersion experiments are used to study the degradation properties. CCK-8 assays and cell adhesion are employed for detecting cell viability, proliferation and adhesion. The results show that the embedded GO additive promotes the formation of blocked pores and small size structures, improves the surface roughness and adhesion strength. In addition, GO additive can effectively reduce the HEV, enhance the corrosion resistance and improve the polarization resistance. And G300 sample exhibits excellent cell viability and cell adhesion.