Tailored Zn content in reactive gas-timing sputtered ZnO nanostructure thin film deposited on Ti implant for enhanced antimicrobial activity

The modification of a titanium surface using tailored Zn content in ZnO nanostructure thin films was fabricated using DC magnetron sputtering which was incorporated with a reactive gas-timing (RGT) technique where the on-off sequence of the gas was controlled. The RGT with optimal O₂ timing provided a grainy nanoporous structure of ZnO thin films, whereas the conventional films demonstrated a nanocolumnar structure along with a uniform surface. In addition, atomic concentration analysis confirmed that the Zn content in thin films depended on the oxygen flow during the deposition. These specific properties of RGT-ZnO thin films could improve the antifungal activity of titanium. We found that the antifungal activity against C. albicans of the RGT-ZnO thin film was more than 99.99% compared to uncoated Ti (p-value < 0.01). It was also greatly higher than those prepared by a conventional technique which had approximately 70%. Therefore, these findings demonstrated that ZnO thin films with tunable morphology and Zn composition could significantly enhance the antifungal property. This could be an alternative strategy to enhance the biological performance of titanium-based materials and reduce infections in dental implants as well.