BACKGROUND: Traditional antibacterial photocatalysts are primarily induced by ultraviolet light to elicit antibacterial reactive oxygen species. New generation visible-light responsive photocatalysts were discovered, offering greater opportunity to use photocatalysts as disinfectants in our living environment. Recently, we found that visible-light responsive platinum-containing titania (TiO2-Pt) exerted high performance antibacterial property against soil-borne pathogens even in soil highly contaminated water. However, its physical and photocatalytic properties, and the application in vivo have not been well-characterized. METHODS: Transmission electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, ultraviolet-visible absorption spectrum and the removal rate of nitrogen oxides were therefore analyzed. The antibacterial performance under in vitro and in vivo conditions was evaluated. RESULTS: The apparent quantum efficiency for visible light illuminated TiO2-Pt is relatively higher than several other titania photocatalysts. The killing effect achieved approximately 2 log reductions of pathogenic bacteria in vitro. Illumination of injected TiO2-Pt successfully ameliorated the subcutaneous infection in mice. CONCLUSIONS: This is the first demonstration of in vivo antibacterial use of TiO2-Pt nanoparticles. When compared to nanoparticles of some other visible-light responsive photocatalysts, TiO2-Pt nanoparticles induced less adverse effects such as exacerbated platelet clearance and hepatic cytotoxicity in vivo. GENERAL SIGNIFICANCE: These findings suggest that the TiO2-Pt may have potential application on the development of an antibacterial material in both in vitro and in vivo settings.
BACKGROUND: Traditional antibacterial photocatalysts are primarily induced by ultraviolet light to elicit antibacterial reactive oxygen species. New generation visible-light responsive photocatalysts were discovered, offering greater opportunity to use photocatalysts as disinfectants in our living environment. Recently, we found that visible-light responsive platinum-containing titania (TiO2-Pt) exerted high performance antibacterial property against soil-borne pathogens even in soil highly contaminated water. However, its physical and photocatalytic properties, and the application in vivo have not been well-characterized. METHODS: Transmission electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, ultraviolet-visible absorption spectrum and the removal rate of nitrogen oxides were therefore analyzed. The antibacterial performance under in vitro and in vivo conditions was evaluated. RESULTS: The apparent quantum efficiency for visible light illuminated TiO2-Pt is relatively higher than several other titania photocatalysts. The killing effect achieved approximately 2 log reductions of pathogenic bacteria in vitro. Illumination of injected TiO2-Pt successfully ameliorated the subcutaneous infection in mice. CONCLUSIONS: This is the first demonstration of in vivo antibacterial use of TiO2-Pt nanoparticles. When compared to nanoparticles of some other visible-light responsive photocatalysts, TiO2-Pt nanoparticles induced less adverse effects such as exacerbated platelet clearance and hepatic cytotoxicity in vivo. GENERAL SIGNIFICANCE: These findings suggest that the TiO2-Pt may have potential application on the development of an antibacterial material in both in vitro and in vivo settings.