Bactericidal activity of copper-deposited TiO2 thin film under weak UV light illumination

被引:277
作者
Sunada, K
Watanabe, T
Hashimoto, K
机构
[1] Univ Tokyo, Adv Sci & Technol Res Ctr, Meguro Ku, Tokyo 1538904, Japan
[2] Kanagawa Acad Sci & Technol, Takatsu Ku, Kawasaki, Kanagawa 2130012, Japan
关键词
D O I
10.1021/es034106g
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
The bactericidal activity of copper-deposited titanium dioxide thin film (Cu/TiO2) was investigated under very weak ultraviolet (UV) light illumination. To elucidate the roles of the film photocatalyst and the deposited copper in the bactericidal activity, cells from a copper-resistant Escherichia coli (E coli) strain were utilized. A decrease in survival rate was not observed with the copper-resistant cells under dark conditions, but when illuminated with a very weak UV intensity of 1 muW/cm(2), the survival rate decreased, suggesting photocatalytic bactericidal activity. The decay curve of survival on the Cu/TiO2 film under very weak UV light illumination consisted of two steps, similar to the survival change of normal E coli on TiO2 films under rather strong UV illumination. The first step is due to the partial decomposition of the outer membrane in the cell envelope by a photocatalytic process, followed by permeation of the copper ions into the cytoplasmic membrane. The second step is due to a disorder of the cytoplasmic membrane caused by the copper ions, which results in a loss of the cell's integrity. These processes explain why the Cu/TiO2 film system shows an effective bactericidal activity even under very weak UV light illumination.
引用
收藏
页码:4785 / 4789
页数:5
相关论文
共 54 条