Biodegradable Zn-Based Implants: Progress, Challenges, and Pathways toward Clinical Translation

As a new generation of biomaterials, biodegradable zinc (Zn)-based implants hold substantial promise for clinical use due to their favorable biocompatibility and controllable degradation behavior. This review summarizes recent progress in Zn-based implants, focusing on the physiological roles of Zn, current Zn-based implant systems, and relevant applicable standards. To address the critical challenges faced in practical applications, such as optimizing corrosion rate, antibacterial performance, and biocompatibility, researchers have employed innovative strategies, including alloying (e.g., Zn-Mg, Zn-Mn, Zn-Li), surface modifications, and functional coatings. Meanwhile, a detailed overview is provided of in vitro and in vivo degradation evaluation systems, advances in preclinical animal studies, and the status of clinical trials, together with regulatory requirements for biodegradable metals set by domestic and international authorities. Key mechanistic and translational bottlenecks that currently limit clinical adoption are identified, together with critical directions for the rational design and standardized evaluation of next-generation Zn-based implants.