Fabrication of Biodegradable Zn-Cu Alloys via Vacuum Hot-pressing Sintering: In Vitro and In Vivo Bone Defect Repair Performance Based on Microstructural Regulation

Biodegradable zinc-based alloys have emerged as highly promising biomaterials for orthopedic applications, but they suffer from insufficient mechanical strength, which hinders their clinical translation. In this study, Zinc-xCopper (Zn-xCu, x = 1, 3, 5   wt%) alloys were fabricated via vacuum hot-pressing sintering, and their mechanical properties, degradation behavior, cell biocompatibility, osteogenic activity, and antibacterial properties were systematically investigated. Specifically, Zn-Cu alloys exhibited superior mechanical performance and regulated degradation kinetics. Benefiting from the remarkable grain refinement effect (grain size reduced from 5.3 μm in pure Zn to 0.74 μm in Zn-5Cu), the Zn-5Cu alloy achieved the highest mechanical strength, with a compressive yield strength of 227.72   MPa, compressive elastic modulus of 8.57   GPa. In terms of degradation performance, the Zn-5Cu alloy displayed an appropriate degradation rate. Furthermore, this alloy could significantly promote the osteogenic differentiation and mineralization of MC3T3-E1 cells. In vivo rat tibias implantation experiments further confirmed its excellent osteogenic activity. Meanwhile, the Zn-Cu alloys also exhibited outstanding antibacterial activity. The results indicate that Zn-Cu alloys have great application potential as biodegradable bone implant materials.