The crucial role of the Seebeck effect in the degradation behavior of Mg-based biomedical alloys

Biodegradable magnesium alloys hold great promise as orthopedic implants due to their bone-matching elastic modulus and capacity to eliminate secondary removal surgery. Nevertheless, the often-ignored role of the thermoelectric effect of Mg alloy biomedical materials in their corrosion process might have led to a research gap in this field. This overlooked role of the thermoelectric effect has prompted this study, which aims to investigate the effects of Zn content on the microstructure, corrosion behavior, and biophysical properties of Mg–3Sn–xZn (x = 0, 1, 3, 5, 7 wt. %) alloys. Specifically, this study evaluates the micro-current generated by degradation-induced galvanic effects, especially the Seebeck effect, and its subsequent impact on cell viability and migration, which are closely related to the investigated microstructure, corrosion behavior, and biophysical properties of Mg–3Sn–xZn alloys. Results indicate that the Mg–3Sn–5Zn alloy exhibits optimal comprehensive performance, demonstrating favorable degradation kinetics, enhanced biocompatibility, notable antibacterial properties, and improved in vitro corrosion resistance. Critically, the degradation-induced micro-current significantly promotes cell viability and migration, thereby facilitating tissue repair. This work establishes an innovative correlation between the alloy's Seebeck coefficient and biocompatibility, offering mechanistic insights for biodegradable bone-repair materials and advancing their clinical translation.