Antibacterial Properties of TiO_2 Layers Formed by Au-Sputtering and Thermal Oxidation of Titanium under Visible Light

摘要

To prevent infection in dental implants using photocatalytic activity under visible-light irradiation, the fabrication of Au-added TiO_2 layers on Ti substrates and their antibacterial properties were studied. Pure Au and Ti-(60,40) molAu alloy films with thicknesses of 10-47 nm were sputtered onto Ti, followed by thermal oxidation in air at 873 K for 1.8 ks to form TiO_2 layers. The antibacterial properties against Escherichia coli, cytotoxicity, and bonding strength to Ti substrates were evaluated. The highest antibacterial activity under visible-light irradiation was obtained when the sputtered film was pure Au and its thickness was 38 nm. Compared with as-polished commercially pure Ti, the number of viable mouse osteoblast-like cells and human gingival fibroblasts on Au-added TiO_2 layers increased after placement in the dark but decreased after visible-light irradiation. The best antibacterial property-bonding strength balance was achieved when the Ti-40 molAu sputtered film with a thickness of 42 nm was formed on Ti. To the best of our knowledge, this study is the first to report the formation of TiO_2 layers with antibacterial activity under visible-light irradiation by combining Au-sputtering and thermal oxidation of Ti.