Susceptibility of Pseudomonas aeruginosa biofilm to UV-A illumination over photocatalytic and non-photocatalytic surfaces
Gage, Joshua Albert
Roberts, T. M.
Duffy, James E.
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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 (1.0mW/cm2) UV-A irradiation. Photocatalytic treatment of planktonic PA01 cultures provided 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.
Gage JP, Roberts TM, Duffy JE, "Susceptibility of Pseudomonas aeruginosa biofilm to UV-A illumination over photocatalytic and non-photocatalytic surfaces," Biofilms, 2005 2(3):155-163