Biodegradable Zn-0.5Li alloy rib plate: Processing procedure development and in vitro performance evaluation

Trauma kills more than four million people worldwide each year, with chest trauma accounting for 25% of these deaths. Rib fractures are the main manifestation of chest trauma. Biodegradable Zn alloys offer a new option to overcome clinical problems caused by permanent rib fracture internal fixation materials, e.g., long-term stress masking and secondary surgery. In this study, the fabrication procedure of biodegradable Zn-0.5Li alloy rib plates is successfully developed, which consists of casting, hot-warm rolling, cutting, and pressing sequentially. Biomechanical three-point bending performance of the Zn alloy rib plates is comparable to that of commercial pure Ti rib plates, much higher than that of pure Zn rib plates. In addition, the Zn alloy exhibits the best antibacterial ability against E. coli and S. aureus among the three materials. Although the Zn alloy exhibits a weaker MC3T3 cytocompatibility than pure Ti, it is better than pure Zn. This study provides a foundation for the future development of various biodegradable Zn alloy rib plates.