Enhanced Mechanical Properties, Corrosion Resistance, Cytocompatibility, Osteogenesis, and Antibacterial Performance of Biodegradable Mg-2Zn-0.5Ca-0.5Sr/Zr Alloys for Bone-Implant Application

Magnesium (Mg) alloys are widely used in bone fixation and bone repair as biodegradable bone-implant materials. However, their clinical application is limited due to their fast corrosion rate and poor mechanical stability. Here, the development of Mg-2Zn-0.5Ca-0.5Sr (MZCS) and Mg-2Zn-0.5Ca-0.5Zr (MZCZ) alloys with improved mechanical properties, corrosion resistance, cytocompatibility, osteogenesis performance, and antibacterial capability is reported. The hot-extruded (HE) MZCZ sample exhibits the highest ultimate tensile strength of 255.8 +/- 2.4 MPa and the highest yield strength of 208.4 +/- 2.8 MPa and an elongation of 15.7 +/- 0.5%. The HE MZCS sample shows the highest corrosion resistance, with the lowest corrosion current density of 0.2 +/- 0.1 mu A cm-2 and the lowest corrosion rate of 4 +/- 2 mu m per year obtained from electrochemical testing, and a degradation rate of 368 mu m per year and hydrogen evolution rate of 0.83 +/- 0.03 mL cm-2 per day obtained from immersion testing. The MZCZ sample shows the highest cell viability in relation to MC3T3-E1 cells among all alloy extracts, indicating good cytocompatibility except at 25% concentration. Furthermore, the MZCZ alloy shows good antibacterial capability against Staphylococcus aureus. Magnesium (Mg) alloys are extensively studied as biodegradable bone-implant materials for bone fixation, bone repair, and cardiovascular stents. However, substantial challenges persist in their clinical application due to their fast corrosion rate and poor mechanical stability. This work introduces improved mechanical properties, corrosion resistance, cytocompatibility, osteogenesis performance, and antibacterial capability of biodegradable Mg-2Zn-0.5Ca-0.5Sr/Zr alloys for bone-implant applications.image