Biodegradable Zn-Mn Alloys with Suitable Mechanical Strength, High Plasticity, and Good Osteogenic Activities for Orthopedic Applications

In recent years, Zn-based materials provide a new option as biodegradable metals for orthopedic applications. To improve the low strength and brittle nature of pure Zn, small amounts of alloying element Mn (0.1, 0.4 and 0.8 wt. %) were added into Zn to fabricate binary Zn-Mn alloys. An extremely high elongation (83.96 ± 2.36%) was achieved in the resulting Zn-0.8wt.%Mn alloy. Moreover, Zn-Mn alloys displayed significantly improved cytocompatibility as compared to pure Zn, according to cell proliferation and morphology analyses. More importantly, a significantly improved osteogenic activity was verified after adding Mn regarding ALP activity and osteogenic expression. Furthermore, Zn-0.8wt.%Mn alloy scaffolds were implanted into the rat femoral condyle for bone defect repairing with pure Ti as control. Enhanced osteogenic activities were confirmed in Zn-0.8Mn alloy in contrast to pure Ti based on Micro-CT and histological results, and favorable in vivo biosafety of Zn-0.8Mn alloy was verified by H&E staining and blood tests. The exceptional mechanical performance and excellent osteogenic capability render Zn-Mn alloy a promising candidate material in the treatment of bone defects or fracture repair.