The effects of the bacterial interaction with visible-light responsive titania photocatalyst on the bactericidal performance

Abstract

Bactericidal activity of traditional titanium dioxide (TiO 2 ) photocatalyst is effective only upon irradiation by ultraviolet light, which restricts the potential applications of TiO 2 for use in our living environments. Recently carbon-containing TiO 2 was found to be photoactive at visible-light illumination that affords the potential to overcome this problem; although, the bactericidal activity of these photocatalysts is relatively lower than conventional disinfectants. Evidenced from scanning electron microscopy and confocal Raman spectral mapping analysis, we found the interaction with bacteria was significantly enhanced in these anatase/rutile mixed-phase carbon-containing TiO 2 . Bacteria-killing experiments indicate that a significantly higher proportion of all tested pathogens including Staphylococcus aureus, Shigella flexneri and Acinetobacter baumannii, were eliminated by the new nanoparticle with higher bacterial interaction property. These findings suggest the created materials with high bacterial interaction ability might be a useful strategy to improve the antimicrobial activity of visible-light-activated TiO 2 .

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

“…As photogenerated ROS are highly reactive and short-lived (19,20), the transport of bacterial cells to the site of surface-generated ROS remains a rate-limiting step in photocatalytic bacterial inactivation (3). Many studies have shown that close contact between bacterial cells and TiO 2 particles increases the extent of oxidative damage (21)(22)(23). The production of capsular EPS has been shown to facilitate bacterial adhesion to various substrates, and bacterial attachment is well explained and predicted by the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory (24).…”

Influence of titanium dioxide modification on the antibacterial properties

“…Due to different surface coatings, photocatalysts have a preferential interaction with bacterial membrane components. By confocal Raman mapping techniques, Cheng et al 27 proved that better bacterial interaction was associated with better pathogenkilling performance. For this reason antibacterial activity of modifi ed titania might be signifi cantly enhanced by carbon.…”

“…Moreover silver resistant bacteria appear rapidly most frequently in human isolates. For example silver-resistant Enterobacter cloacae strain was isolated from a chronic leg ulcer after only three weeks of treatment with silver-based dressings 27 . For that reason use of silver modifi ed nanomaterials, e.g., titania may affect the bacterial resistance, thereby, can be a limiting factor in development of disinfections technologies.…”

Survival of Staphylococcus aureus exposed to UV radiation on the surface of ceramic tiles coated with TiO2

“…In general, it is believed that the photocatalytic reactions in titanium dioxide are raised by the UV radiation of wavelength 388 nm or less (Anon 2004). For this reason, in the most of the studies aqueous solutions of TiO 2 powder were mixed with bacter-ial suspensions and irradiated with UV light with a wavelength of 365 nm, which is considered harmless to humans, or visible light was used for excitation of photocatalysis (Maness et al 1999, Kim et al 2003, Tsuang et al 2008, Cheng et al 2009). …”