Comparative Study of the Effects of Nano ZnO and CuO on the Biodegradation, Biocompatibility, and Antibacterial Properties of Micro-arc Oxidation Coating of Magnesium Alloy

This research systematically examined the degradation, antibacterial effects, and biocompatibility of micro-arc oxidation (MAO) coatings with nano CuO and ZnO on extruded Mg alloys. Both copper (Cu) and Zinc (Zn) possess antibacterial properties. The findings demonstrated that adding ZnO will appreciably reduce the degradation rate of MAO-coating alloy due to the self-sealing micro holes. CuO + MAO coating exhibited excellent antibacterial performance, with an antibacterial rate of over 90% within 6 h co-cultured with Staphylococcus aureus. Similarly, the antibacterial rate of ZnO + MAO coating reached 90% after 12 h co-culture. Cytotoxicity test using MG63 cell indicated that the incorporation of CuO and ZnO did not notably affect the cell viability rate of the coating. Moreover, after 14 days of culture, the CuO + MAO and ZnO + MAO coated samples exhibited higher alkaline phosphatase (ALP) activity than the MAO-coated and uncoated samples, suggesting favorable osteogenic properties.