Chang Chen, Ruimin Tang, Yifeng Guo, Xiaoli Lei, Qian Min, Yujiao Lu, Yilong Dai
In response to the challenges of excessively rapid degradation and inadequate antibacterial properties in medical magnesium alloys, this study investigates the regulatory effect of ion implantation technology on the surface characteristics of ZM21 magnesium alloy, with particular emphasis on evaluating the influence of single Ti ion implantation (ZM21-Ti) and Ti/Ag co-implantation (ZM21-Ti/Ag) on microstructure, corrosion behavior, in vitro degradation, biocompatibility, and antibacterial performance. XRD and XPS analyses confirmed the successful incorporation of Ti and Ag elements into the alloy surface, where they exist predominantly as TiO 2 , metallic Ag, and Ag 2 O. Electrochemical tests and in vitro degradation experiments revealed that Ti ion implantation significantly improves corrosion resistance, achieving the lowest corrosion current density (I corr ) of 3.05 μA·cm -2 and the slowest degradation rate. In contrast, Ti/Ag co-implanted samples exhibited accelerated corrosion due to galvanic coupling, resulting in a higher I corr of 13.96 μA·cm -2 . Cell culture assays demonstrated that ZM21-Ti possesses favorable cytocompatibility and effectively promotes the expression of osteogenic genes and mineralized nodule formation. However, ZM21-Ti/Ag showed notable cytotoxicity under high-concentration extract conditions. With respect to antibacterial activity, ZM21-Ti/Ag displayed superior antibacterial efficacy, attributed to its faster degradation and enhanced release of antimicrobial Ag + ions. Meanwhile, ZM21-Ti achieved a balanced performance between moderate antibacterial capability (73.67% inhibition rate) and strong osteogenic potential. These findings suggest that Ti ion implantation is an effective surface modification approach for improving both corrosion resistance and biocompatibility of ZM21 magnesium alloy without compromising its antibacterial functionality.