title: Photocatalytic antibacterial effects on TiO2-anatase upon UV-A and UV-A/VIS threshold irradiation.
abstract: Photocatalysis mediated by the anatase modification of titanium dioxide (TiO2) has shown antibacterial effects in medical applications. The aim of this study was to investigate the possibility of expanding the excitation wavelengths for photocatalytic antibacterial effects from ultraviolet (UV) into the visible light range. After deposition of salivary pellicle and adhesion of Streptococcus gordonii on anatase, different irradiation protocols were applied to induce photocatalysis: ultraviolet A (UV-A) > 320 nm; ultraviolet/visible (UV-A/VIS) light > 380 nm and > 390 nm; and VIS light 400-410 nm. A quartz crystal microbalance with dissipation (QCM-D) tests and microscopic examination were used to observe the photoinduced antibacterial effects. Salivary pellicle could be photocatalytically decomposed under all irradiation protocols. In contrast, effective photocatalytic attack of bacteria could be observed by UV-A as well as by UV-A/VIS at 380 nm < λ < 390 nm only. Wavelengths above 380 nm show promise for in situ therapeutic antifouling applications.
authors.affiliation: a Section Medical Materials Science & Technology , University Hospital Tübingen , Tübingen , Germany.
authors.forename: Yanyun
authors.initials: Y
authors.lastname: Wu
authors.affiliation: a Section Medical Materials Science & Technology , University Hospital Tübingen , Tübingen , Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Geis-Gerstorfer
authors.affiliation: a Section Medical Materials Science & Technology , University Hospital Tübingen , Tübingen , Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Scheideler
authors.affiliation: a Section Medical Materials Science & Technology , University Hospital Tübingen , Tübingen , Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Rupp
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D057219:Biofouling; D002384:Catalysis; D044622:Dental Pellicle / Q000382:microbiology; D006801:Humans; D008027:Light; D055668:Photochemical Processes; D058525:Quartz Crystal Microbalance Techniques; D014025:Titanium / Q000494:pharmacology*; D014466:Ultraviolet Rays
chemical_list: D000900:Anti-Bacterial Agents; C009495:titanium dioxide; D014025:Titanium
keywords: Photocatalysis; QCM-D; UV-A/VIS; anatase; antibacterial; live/dead staining