In vitro degradation and antibacterial property of a copper-containing micro-arc oxidation coating on Mg-2Zn-1Gd-0.5Zr alloy

Copper (Cu) has a good antibacterial effect and micro-arc oxidation (MAO) coating has good corrosion resistance for magnesium (Mg) alloys. If they are combined together, the coated Mg alloy is expected to have both good corrosion resistance and antibacterial effect. In this work, the degradation, antibacterial property and cytotoxicity of a Cu-containing MAO coating on an extruded Mg-2Zn-1Gd-0.5Zr alloy were systematically studied. The results revealed that the addition of Cu could further improve the degradation resistance of MAO coated alloy. After two weeks immersion, the corrosion rate of Cu + MAO coated alloy was 0.16 mm/y, lower than those of both MAO coated and uncoated alloy. The release of Cu2+ from Cu + MAO coated alloy inhibited the bacterial proliferation. After 12 h co-culture, the antibacterial rate reached 96%. Cytotoxicity test (MG63 cell) showed that Cu + MAO coated alloy had good biocompatibility. The Cu + MAO coating has great potential for application on Mg alloys due to its good corrosion resistance, antibacterial property and good biocompatibility.