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Effects of Photoactivated Titanium Dioxide Nanopowders and Coating on Planktonic and Biofilm Growth of Pseudomonas aeruginosa
Author(s) -
Polo Andrea,
Diamanti Maria Vittoria,
Bjarnsholt Thomas,
Høiby Niels,
Villa Federica,
Pedeferri Maria Pia,
Cappitelli Francesca
Publication year - 2011
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.2011.00972.x
Subject(s) - pseudomonas aeruginosa , biofilm , titanium dioxide , coating , chemistry , microbiology and biotechnology , materials science , bacteria , biology , metallurgy , organic chemistry , genetics
We exploited the ability of photocatalytic titanium dioxide (TiO 2 ) as an agent for the biofilm control. Two photocatalytic systems were investigated: a 3 g L −1 suspension of TiO 2 nanopowder in demineralized water and glass slides coated with a TiO 2 thin film, achieved by sol‐gel deposition. A running protocol for the photoactivation of TiO 2 was set up using the dye rhodamine B. The microorganisms studied were Pseudomonas stutzeri , Pseudomonas aeruginosa and a Bacillus cereus ‐group as planktonic cells. P. aeruginosa biofilms were also studied at both the solid‐liquid and the solid‐air interface. The TiO 2 nanopowder produced 1‐log reduction of Bacillus sp. planktonic cells in 24 h, 2‐log reduction of P . stutzeri planktonic cells in 30 min and 1‐log reduction of P . aeruginosa planktonic cells in 2 h compared with non–photo‐activated TiO 2 . TiO 2 thin film produced almost a complete eradication of P . aeruginosa planktonic cells (initial concentration 10 8 cells mL −1 ) in 24 h compared to a 3‐log reduction caused by UV‐A light alone. In contrast, neither the photocatalytic treatment with TiO 2 film nor that with TiO 2 nanopowder had any effect on P. aeruginosa biofilms at all the interfaces investigated. Possible explanations for these findings, and for the discrepancy between this work and literature data, are discussed.