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Visible-Light-Induced Bactericidal Activity of a Nitrogen-Doped Titanium Photocatalyst against Human Pathogens

Wong, Ming-Show, Chu, Wen-Chen, Sun, Der-Shan, Huang, Hsuan-Shun, Chen, Jiann-Hwa, Tsai, Pei-Jane, Lin, Nien-Tsung, Yu, Mei-Shiuan, Hsu, Shang-Feng, Wang, Shih-Lien, Chang, Hsin-Hou
Applied and environmental microbiology 2006 v.72 no.9 pp. 6111-6116
Acinetobacter baumannii, Escherichia coli, Listeria monocytogenes, Shigella flexneri, Staphylococcus aureus, Streptococcus pyogenes, Vibrio parahaemolyticus, antibacterial properties, humans, pathogens, titanium, titanium dioxide, ultraviolet radiation
The antibacterial activity of photocatalytic titanium dioxide (TiO₂) substrates is induced primarily by UV light irradiation. Recently, nitrogen- and carbon-doped TiO₂ substrates were shown to exhibit photocatalytic activities under visible-light illumination. Their antibacterial activity, however, remains to be quantified. In this study, we demonstrated that nitrogen-doped TiO₂ substrates have superior visible-light-induced bactericidal activity against Escherichia coli compared to pure TiO₂ and carbon-doped TiO₂ substrates. We also found that protein- and light-absorbing contaminants partially reduce the bactericidal activity of nitrogen-doped TiO₂ substrates due to their light-shielding effects. In the pathogen-killing experiment, a significantly higher proportion of all tested pathogens, including Shigella flexneri, Listeria monocytogenes, Vibrio parahaemolyticus, Staphylococcus aureus, Streptococcus pyogenes, and Acinetobacter baumannii, were killed by visible-light-illuminated nitrogen-doped TiO₂ substrates than by pure TiO₂ substrates. These findings suggest that nitrogen-doped TiO₂ has potential application in the development of alternative disinfectants for environmental and medical usages.