title: Photocatalytic disinfection using titanium dioxide: spectrum and mechanism of antimicrobial activity.
abstract: The photocatalytic properties of titanium dioxide are well known and have many applications including the removal of organic contaminants and production of self-cleaning glass. There is an increasing interest in the application of the photocatalytic properties of TiO(2) for disinfection of surfaces, air and water. Reviews of the applications of photocatalysis in disinfection (Gamage and Zhang 2010; Chong et al., Wat Res 44(10):2997-3027, 2010) and of modelling of TiO(2) action have recently been published (Dalrymple et al. , Appl Catal B 98(1-2):27-38, 2010). In this review, we give an overview of the effects of photoactivated TiO(2) on microorganisms. The activity has been shown to be capable of killing a wide range of Gram-negative and Gram-positive bacteria, filamentous and unicellular fungi, algae, protozoa, mammalian viruses and bacteriophage. Resting stages, particularly bacterial endospores, fungal spores and protozoan cysts, are generally more resistant than the vegetative forms, possibly due to the increased cell wall thickness. The killing mechanism involves degradation of the cell wall and cytoplasmic membrane due to the production of reactive oxygen species such as hydroxyl radicals and hydrogen peroxide. This initially leads to leakage of cellular contents then cell lysis and may be followed by complete mineralisation of the organism. Killing is most efficient when there is close contact between the organisms and the TiO(2) catalyst. The killing activity is enhanced by the presence of other antimicrobial agents such as Cu and Ag.
authors.affiliation: Centre for Parasitology and Disease Research, School of Environment and Life Sciences, University of Salford, The Crescent, Salford, Greater Manchester, UK. h.a.foster@salford.ac.uk
authors.forename: Howard A
authors.initials: HA
authors.lastname: Foster
authors.forename: Iram B
authors.initials: IB
authors.lastname: Ditta
authors.forename: Sajnu
authors.initials: S
authors.lastname: Varghese
authors.forename: Alex
authors.initials: A
authors.lastname: Steele
mesh_terms: D056894:Amoebozoa / Q000187:drug effects; D001419:Bacteria / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D000460:Chlorophyta / Q000187:drug effects; D004202:Disinfectants / Q000378:metabolism*; D004203:Disinfection / Q000379:methods*; D005658:Fungi / Q000187:drug effects; D050296:Microbial Viability / Q000187:drug effects; D055668:Photochemical Processes; D014025:Titanium / Q000378:metabolism*; D014780:Viruses / Q000187:drug effects
chemical_list: D004202:Disinfectants; C009495:titanium dioxide; D014025:Titanium