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Susceptibility of Pseudomonas aeruginosa biofilm to UV-A illumination over photocatalytic and non-photocatalytic surfaces

Published online by Cambridge University Press:  27 September 2005

J. P. Gage
Affiliation:
Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT 59717, USA
T. M. Roberts
Affiliation:
Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT 59717, USA
J. E. Duffy
Affiliation:
Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT 59717, USA

Abstract

The susceptibility of Pseudomonas aeruginosa (PA01) bacteria to ultraviolet-A (UV-A) light in photocatalytic and non-photocatalytic systems was investigated. Thin films of TiO2 were deposited on glass slides using a dip-coating method. Disinfection of both planktonic and biofilm bacterial cells was studied over both coated and uncoated slides exposed to low intensity (1.0 mW/cm2) UV-A irradiation. Photocatalytic treatment of planktonic PA01 cultures pro-vided a 4-log reduction in the number of viable cells in 3 h whereas UV light alone produced a 1-log reduction. For biofilm bacteria, photocatalytic treatment did not enhance killing relative to UV treatment alone; however, the UV illumination resulted in a 2- to 3-log reduction in viable cells as compared with non-illuminated controls. Possible explanations for the discrepancy between susceptibility of planktonic and biofilm bacteria to photocatalytic oxidation are discussed.

Type
Research Articles
Copyright
© 2005 Cambridge University Press

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