Antibacterial properties of Cu-doped TiO<sub>2</sub> prepared by chemical and heat treatment of Ti metal
Kanae Suzuki, Taishi Yokoi, Misato Iwatsu, Maiko Furuya, Kotone Yokota, Takayuki Mokudai, Hiroyasu Kanetaka, Masakazu Kawashita
Abstract
In this study, we proposed Cu-doped TiO2, prepared by the alkaline and heat treatment of titanium (Ti) metal, for use in dental applications because of its bone-bonding and antibacterial properties generated by the release of Cu ions and visible-light-responsive photocatalysis. We successfully prepared Cu-doped TiO2 on a Ti chip surface with a Cu content of 7 at.%. The apatite-forming ability of the Cu-doped TiO2 was evaluated using a simulated body fluid and it was found that apatite formation occurred. Hence, we concluded that Cu-doped TiO2 exhibits bone-bonding properties. The antibacterial properties of Cu-doped TiO2 for Escherichia coli were higher than those of non-doped TiO2 under visible light irradiation. The enhanced antibacterial effect was mainly caused by the visible-light-responsive photocatalysis of Cu-doped TiO2. We confirmed that the reactive oxygen species generated by the visible-light-responsive photocatalysis of Cu-doped TiO2 were hydroxyl radicals formed by the reaction of hydroxide ions (OH−) and holes (h+). Our findings are useful for the development of novel bioactive TiO2-based coatings and bulk materials with antibacterial properties by Cu doping.