Optimized Ag enhances antibacterial activity and corrosion resistance of extruded Mg-2Zn-0.2Ca alloy

Infection remains a major cause of implant failure, motivating the development of biodegradable metals with intrinsic antibacterial activity. This study investigated how minor silver (Ag) addition regulates the degradation and antibacterial performance of extruded Mg-2Zn-0.2Ca alloys. Adding 0.1 wt % Ag significantly reduced the degradation rate to 0.14 ± 0.04 mm/y after 672 h of immersion, lower than WE43 (0.66 ± 0.05 mm/y), whereas higher Ag contents accelerated degradation. Extracts from the Ag-free alloy showed moderate antibacterial rates of 43.4% ± 0.06% and 62.4% ± 3.55% against Escherichia coli and Staphylococcus aureus, respectively. With 0.1 wt % Ag, these rates increased significantly to 83.4% ± 3.82% and 92.1% ± 2.66%, comparable to WE43. Adenosine triphosphate assays, reactive oxygen species detection, and electron paramagnetic resonance analysis indicated that the enhanced antibacterial activity of Ag-containing alloys involved adenosine triphosphate depletion and oxidative stress. Overall, ZXQ0.1 represents a promising candidate for further investigation as a biodegradable antimicrobial magnesium alloy.