Antibacterial Properties of Visible-Light-Responsive Carbon-Containing Titanium Dioxide Photocatalytic Nanoparticles against Anthrax.
The bactericidal activity of conventional titanium dioxide (TiO₂) photocatalyst is effective only on irradiation by ultraviolet light, which restricts the applications of TiO₂ for use in living environments. Recently, carbon-containing TiO₂ nanoparticles [TiO₂(C) NP] were found to be a visible-light-responsive photocatalyst (VLRP), which displayed significantly enhanced antibacterial properties under visible light illumination. However, whether TiO₂(C) NPs exert antibacterial properties againstBacillus anthracisremains elusive. Here, we evaluated these VLRP NPs in the reduction of anthrax-induced pathogenesis. Bacteria-killing experiments indicated that a significantly higher proportion (40%-60%) of all testedBacillusspecies, includingB. subtilis,B. cereus,B. thuringiensis, andB. anthracis, were considerably eliminated by TiO₂(C) NPs. Toxin inactivation analysis further suggested that the TiO₂(C) NPs efficiently detoxify approximately 90% of tested anthrax lethal toxin, a major virulence factor of anthrax. Notably, macrophage clearance experiments further suggested that, even under suboptimal conditions without considerable bacterial killing, the TiO₂(C) NP-mediated photocatalysis still exhibited antibacterial properties through the reduction of bacterial resistance against macrophage killing. Our results collectively suggested that TiO₂(C) NP is a conceptually feasible anti-anthrax material, and the relevant technologies described herein may be useful in the development of new strategies against anthrax.
Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien 97004, Taiwan. dssun@mail.tcu.edu.tw.
Der-Shan
DS
Sun
Institute of Microbiology and Immunology, National Defense Medical Center, Taipei 11490, Taiwan. jhkau@ndmctsgh.edu.tw.|Institute of Preventive Medicine, National Defense Medical Center, Taipei 23742, Taiwan. jhkau@ndmctsgh.edu.tw.
Jyh-Hwa
JH
Kau
Institute of Preventive Medicine, National Defense Medical Center, Taipei 23742, Taiwan. jhhhuang@ndmctsgh.edu.tw.
Hsin-Hsien
HH
Huang
Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan. tyh@mail.ntust.edu.tw.
Yao-Hsuan
YH
Tseng
Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien 97004, Taiwan. englishbiology@yahoo.com.tw.
Wen-Shiang
WS
Wu
Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien 97004, Taiwan. hhchang@mail.tcu.edu.tw.
Hsin-Hou
HH
Chang
TiO2; anthrax spore; antibacterial agents; carbon-containing TiO2; visible light responsive photocatalyst