title: Role of dopant concentration, crystal phase and particle size on microbial inactivation of Cu-doped TiO2 nanoparticles.
abstract: The properties of Cu-doped TiO(2) nanoparticles (NPs) were independently controlled in a flame aerosol reactor by varying the molar feed ratios of the precursors, and by optimizing temperature and time history in the flame. The effect of the physico-chemical properties (dopant concentration, crystal phase and particle size) of Cu-doped TiO(2) nanoparticles on inactivation of Mycobacterium smegmatis (a model pathogenic bacterium) was investigated under three light conditions (complete dark, fluorescent light and UV light). The survival rate of M. smegmatis (in a minimal salt medium for 2 h) exposed to the NPs varied depending on the light irradiation conditions as well as the dopant concentrations. In dark conditions, pristine TiO(2) showed insignificant microbial inactivation, but inactivation increased with increasing dopant concentration. Under fluorescent light illumination, no significant effect was observed for TiO(2). However, when TiO(2) was doped with copper, inactivation increased with dopant concentration, reaching more than 90% (>3 wt% dopant). Enhanced microbial inactivation by TiO(2) NPs was observed only under UV light. When TiO(2) NPs were doped with copper, their inactivation potential was promoted and the UV-resistant cells were reduced by over 99%. In addition, the microbial inactivation potential of NPs was also crystal-phase-and size-dependent under all three light conditions. A lower ratio of anatase phase and smaller sizes of Cu-doped TiO(2) NPs resulted in decreased bacterial survival. The increased inactivation potential of doped TiO(2) NPs is possibly due to both enhanced photocatalytic reactions and leached copper ions.
authors.affiliation: Department of Energy, Environmental and Chemical Engineering, Washington University in St Louis, St Louis, MO 63130, USA.
authors.forename: Manoranjan
authors.initials: M
authors.lastname: Sahu
authors.forename: Bing
authors.initials: B
authors.lastname: Wu
authors.forename: Liying
authors.initials: L
authors.lastname: Zhu
authors.forename: Craig
authors.initials: C
authors.lastname: Jacobson
authors.forename: Wei-Ning
authors.initials: WN
authors.lastname: Wang
authors.forename: Kristen
authors.initials: K
authors.lastname: Jones
authors.forename: Yogesh
authors.initials: Y
authors.lastname: Goyal
authors.forename: Yinjie J
authors.initials: YJ
authors.lastname: Tang
authors.forename: Pratim
authors.initials: P
authors.lastname: Biswas
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D003300:Copper / Q000737:chemistry* / Q000494:pharmacology; D006801:Humans; D050296:Microbial Viability / Q000187:drug effects* / Q000528:radiation effects; D009165:Mycobacterium Infections, Nontuberculous / Q000188:drug therapy; D020102:Mycobacterium smegmatis / Q000187:drug effects* / Q000528:radiation effects; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D014025:Titanium / Q000737:chemistry* / Q000494:pharmacology; D014466:Ultraviolet Rays
chemical_list: D000900:Anti-Bacterial Agents; C009495:titanium dioxide; D003300:Copper; D014025:Titanium