Biocompatibility and electrochemical evaluation of ZrO2 thin films deposited by reactive magnetron sputtering on MgZnCa alloy

Abstract

• Sputtered ZrO 2 nanocoatings on a MgZnCa alloy provides corrosion protection. • The ZrO 2 coated Mg alloy reduced the H 2 by half during the first 5 h. • The ZrO 2 -coated Mg alloy presented cell viability close to 100%. • Biofilm formation was avoided in the ZrO 2 -coated alloy. Biodegradable magnesium alloys are promising candidates for temporary fracture fixation devices in orthopedics; nevertheless, its fast degradation rate at the initial stage after implantation remains as one of the main challenges to be resolved. ZrO 2 -based coatings to reduce the degradation rate of the Mg-implants are an attractive solution since they show high biocompatibility and stability. In this work, the degradation, cytotoxicity, and antibacterial performance of ZrO 2 thin films deposited by magnetron sputtering on a Mg-Zn-Ca alloy was evaluated. Short-term degradation of ZrO 2 -coated and uncoated samples was assessed considering electrochemical techniques and H 2 evolution (gas chromatography). Additionally, long term degradation was assessed by mass-loss measurements. The results showed that a 380 nm ZrO 2 coating reduces the degradation rate and H 2 evolution of the alloy during the initial 3 days after immersion but allows the degradation of the bare alloy for the long-term. The ZrO 2 coating does not compromise the biocompatibility of the alloy and permits better cell adhesion and proliferation of mesenchymal stem cells directly on its surface, in comparison to the bare alloy. Finally, the ZrO 2 coating prevents the adhesion and biofilm formation of S. aureus .