Improved biocompatibility and antibacterial property of zinc alloy fabricated with γ-polyglutamic acid-g-dopamine/copper coatings for orthopedic implants

Zinc-lithium (Zn-Li) alloys have attracted considerable attention as potential biodegradable orthopedic implant materials. However, the biocompatibility and antibacterial property need further improvement to meet the clinical requirements. In this study, poly(γ-glutamic acid)-g-dopamine/copper (γ-PGA-g-DA/Cu) hybrid coatings were fabricated on a Zn alloy to improve its biocompatibility and antibacterial performance. Corrosion analysis in simulated body fluid indicated that the γ-PGA-g-DA/Cu coatings afforded tunable degradation rates of Zn alloys. The cytotoxicity evaluation revealed that the presence of copper ions in the coatings could reduce the cytotoxicity problem caused by zinc ions and enhance the biocompatibility of Zn alloy. In vitro antibacterial tests exhibited that the antibacterial activity of Zn alloy enhanced due to the γ-PGA-g-DA/Cu coatings and the antibacterial performance of γ-PGA-g-DA/Cu coated samples increased with increasing copper content of the coatings. In summary, γ-PGA-g-DA/Cu coatings provide a feasible strategy to design Zn alloy implant materials with improved functional performance.