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Citation
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HERO ID
90597
Reference Type
Journal Article
Title
Disinfection of surfaces by photocatalytic oxidation with titanium dioxide and UVA light
Author(s)
Kuhn, KP; Chaberny, IF; Massholder, K; Stickler, M; Benz, VW; Sonntag, HG; Erdinger, L
Year
2003
Is Peer Reviewed?
Yes
Journal
Chemosphere
ISSN:
0045-6535
EISSN:
1879-1298
Volume
53
Issue
1
Page Numbers
71-77
Language
English
PMID
12892668
DOI
10.1016/S0045-6535(03)00362-X
Web of Science Id
WOS:000184682300008
Abstract
Particularly in microbiological laboratories and areas in intensive medical use, regular and thorough disinfection of surfaces is required in order to reduce the numbers of bacteria and to prevent bacterial transmission. The conventional methods of disinfection with wiping are not effective in the longer term, cannot be standardized, are time- and staff-intensive and use aggressive chemicals. Disinfection with hard ultraviolet C (UVC) light is usually not satisfactory, as the depth of penetration is inadequate and there are occupational medicine risks. Photocatalytic oxidation on surfaces coated with titanium dioxide (TiO2) might offer a possible alternative. In the presence of water and oxygen, highly reactive OH-radicals are generated by TiO2 and mild ultraviolet A (UVA). These radicals are able to destroy bacteria, and may therefore be effective in reducing bacterial contamination. Direct irradiation with UVC however can produce areas of shadow in which bacteria are not inactivated. Using targeted light guidance and a light-guiding sheet (out of a UVA-transmittant, Plexiglas, for example), as in the method described in the present study, bacterial inactivation over the entire area is possible. The effectiveness of the method was demonstrated using bacteria relevant to hygiene such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecium. For these bacteria, a reduction efficiency (RE) more than 6 log10 steps in 60 min was observed. Using Candida albicans, a RE of 2 log10 steps in 60 min was seen. Light and scanning electron microscopic examinations suggest that the germ destruction achieved takes place through direct damage to cell walls caused by OH-radicals.
Keywords
Antibacterial effects; Free radicals; Kinetic; UV-irradiation; Light-guiding materials; Photocatalysis
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