Impact of copper on corrosion behavior, biocompatibility and antibaterial activity of biodegradable Zn-3Mg-xCu alloys for orthopedic applications

Abstract

Biodegradable zinc (Zn) based materials have been regarded as promising candidates for orthopedic applications owing to their suitable biodegradability. However, pure Zn exhibited poor mechanical performance and inadequate biofunctionality, which restricted its biomedical applications. Herein, biodegradable Zn-Mg-Cu alloys were developed to enhance the mechanical strength of the Zn matrix and endow the alloys with antibacterial activity. The effect of Cu addition on corrosion behavior, biocompatibility and antibacterial activity of biodegradable Zn-3Mg-xCu alloys was systematically investigated. In vitro immersion test revealed that Zn-3Mg-1Cu exhibited an increasing corrosion rate of 0.0504 mm y⁻¹. The relative cell availability of MC3T3-E1 cells was over 70% after co-culture with 2-fold diluted extracts of the Zn-3Mg-xCu alloy for 3 d, indicating acceptable cytotoxicity. The Cu addition could enhance the antibacterial activity of the Zn-3Mg matrix, and Zn-3Mg-1Cu alloy exhibited the highest inhibition zone diameter (IZD) values of 10.4 mm and 6.0 mm against S. aureus and E. coli, respectively. Overall, the Zn-3Mg-1Cu could be recognized as a promising biodegradable orthopedic material owing to favorable degradation behavior, satisfying biocompatibility, and substantial antibacterial ability.