In vitro and in vivo evaluation of high-strength Mg-Zn-Zr-Mn alloy: Promising biocompatibility and degradation for medical translations

Magnesium alloys have gained popularity in orthopedic implants due to their excellent biocompatibility and biodegradability, which eliminates the need for secondary surgeries for removal. However, uncontrolled rapid degradation of most magnesium alloys can lead to early failure of implants with unexpected accumulation of gas, disturbing regeneration of surrounding tissues. In this article, we introduce new Mg-Zn-Zr-Mn magnesium alloys with biocompatible elements in low concentrations, which can form single-phase alloy and diminish corrosion due to galvanic corrosion due to multiple phases. These alloys also demonstrated outstanding mechanical properties with tensile strength of 332 ​MPa and excellent biocompatibility. Degradation tests were conducted in vitro by electrochemical tests and measuring mass loss and hydrogen gas released, and nearly constant degradation behavior was observed. In vivo degradation experiments were done using goats as models, and long-term observation demonstrated excellent biocompatibility and controlled degradation pattern of our new Mg alloys. Our results provided insights into the in vitro and in vivo performance of our new Mg alloys, and they can be highly promising for widespread use in orthopedic implants.