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

Abstract

The antibacterial activity of photocatalytic titanium dioxide (TiO 2 ) substrates is induced primarily by UV light irradiation. Recently, nitrogen-and carbon-doped TiO 2 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 TiO 2 substrates have superior visible-light-induced bactericidal activity against Escherichia coli compared to pure TiO 2 and carbon-doped TiO 2 substrates. We also found that protein-and light-absorbing contaminants partially reduce the bactericidal activity of nitrogen-doped TiO 2 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 TiO 2 substrates than by pure TiO 2 substrates. These findings suggest that nitrogen-doped TiO 2 has potential application in the development of alternative disinfectants for environmental and medical usages.

A comparative study of the bactericidal effect of photocatalytic oxidation by TiO2 on antibiotic‐resistant and antibiotic‐sensitive bacteria

“…Previous studies have suggested that TiO 2 photocatalysis on the surface of microbes may generate extremely active electron holes and ROS that attack the outer layer of the bacterium. 11,37 The oxidation of the outer membrane of bacteria, which contains lipids, peptidoglycans and teichoic acid, might result in subsequent cell death. Therefore, the extent of bacterial killing may be inversely proportional to the thickness and complexity of the cell wall and membrane.…”

Biocompatibility and antibacterial activity of nitrogen-doped titanium dioxide nanoparticles for use in dental resin formulations

“…14,54,55 Several groups have demonstrated effective bacterial and fungal reduction using N-TiO 2 NPs and films. [56][57][58] In the present work, a repeatable, dose-dependent (0-200 μg/mL) toxicity toward E. coli resulted upon blue light treatment (Figure 8). An approximately 1-log reduction in bacterial population was observed with the highest concentration of particles.…”

Dual Roles of Capsular Extracellular Polymeric Substances in Photocatalytic Inactivation of Escherichia coli: Comparison of E. coli BW25113 and Isogenic Mutants

“…n recent years, heterogeneous photocatalytic processes that use semiconductor catalysts have emerged as promising microbial disinfection technologies (1)(2)(3)(4)(5)(6)(7). Among the various photocatalysts being used, titanium dioxide (TiO 2 ) has received the greatest interest and has been extensively studied because of its efficiency and perceived environmental safety.…”