Hydrothermal growth of hydroxyapatite and ZnO bilayered nanoarrays on magnesium alloy surface with antibacterial activities

Magnesium alloy (MgA) has been extensively used as orthopedic and cardiovascular scaffolds in virtue of its good biocompatibility, unique biodegradability and excellent mechanical properties. However, poor corrosion resistance and easy infection after implantation seriously limit the potential applications of MgA in the biomedical field. Herein, we fabricated bilayered nanoarrays of hydroxyapatite nanorods (HANRs) and ZnO nanorods (ZnONRs) onto the surface of MgA (MgA-MgO-HANRs-ZnONRs) via micro-arc oxidation (MAO) treatment, microwave-assisted hydrothermal and hydrothermal methods. The morphology and chemical composition of MgA-MgO-HANRs-ZnONRs was characterized by FE-SEM, XRD and EDS, indicating that HANRs-ZnONRs bilayered nanoarrays were fabricated on the surface of MgA-MgO. The surface of MgA-MgO-HANRs-ZnONRs exhibited excellent hydrophilicity as evidenced by the low water contact angle of 3°. Compared with the original MgA, the corrosion resistance of MgA-MgO-HANRs-ZnONRs was obviously improved with decreasing the corrosive current density ( i corr ) of 2 orders of magnitude. The MgA-MgO-HANRs-ZnONRs performed excellent antibacterial properties with the bactericidal rate of 96.5% against S. aureus and 94.3% against E. coli .