Fabrication and characterization of ZnO-coated TiO2 nanotube arrays

In this study, we prepared highly ordered TiO2 nanotube arrays on Ti through an anodizing process. Then, utilizing its proven antibacterial properties, we coated our TiO2 nanotubes (TiO2-NTs) with ZnO using the sol-gel method. We characterized the morphology, structure, and composition of the ZnO-coated TiO2 nanotubes (ZnO-TNTs) using field-emission scanning electron microscopy, X-ray diffraction, and energy dispersive spectroscopy, respectively. We investigated surface topography and roughness of the coatings by atomic force microscopy operated in the tapping mode. Our results revealed impurity-free, anatase-phase TiO2 nanotubes that are uniformly coated with a ZnO layer. Finally, we tested the antibacterial activity of ZnO-TNTs against Staphylococcus aureus, and found ZnO-TNTs significantly improved the antibacterial properties of Ti implants. We conclude that ZnO-TNTs provide Ti with antibacterial activity, which highlights its potential in orthopedic and dental implants.