The effects of Cu and Mn on the microstructure, mechanical, corrosion properties and biocompatibility of Zn–4Ag alloy

Zinc (Zn) alloys have been paid increasing attention in the field of biodegradable implantable materials due to their moderate degradation rate compared to magnesium (Mg) and iron (Fe) alloys. In this study, Zn–4Ag, Zn–4Ag–Cu and Zn–4Ag–Mn were prepared to investigate the effects of Cu and Mn elements on the microstructure and properties of Zn–4Ag alloys, and the addition of Cu and Mn improved the mechanical properties and degradation rate of Zn–4Ag alloys. The tensile strength of Zn–Ag after rolling was increased from 141.9 MPa to 168.4 MPa and 206.3 MPa after the addition of Cu and Mn. The degradation rate of Zn–4Ag increased from 0.17 mm/year to 0.22 mm/year and 0.39 mm/year in the first 5 days after the addition of Cu and Mn. The cytotoxicity testing showed good biocompatibility for human umbilical vein endothelial cells (HUVEC) in as-rolled Zn–4Ag–Mn diluted 4 times, and its cytotoxicity showed grade 0 or 1 toxicity with the cell survival rate of 83.7%. The antibacterial experiment showed the highest antibacterial rate for methicillin-resistant Staphylococcus aureus (MRSA) in as-rolled Zn–4Ag–Cu with the antibacterial rate of 90.3%.