Effects of Photoactivated Titanium Dioxide Nanopowders and Coating on Planktonic and Biofilm Growth of Pseudomonas aeruginosa

TY - JOUR

T1 - Effects of Photoactivated Titanium Dioxide Nanopowders and Coating on Planktonic and Biofilm Growth of Pseudomonas aeruginosa

AU - Polo, Andrea

AU - Diamanti, Maria Vittoria

AU - Bjarnsholt, Thomas

AU - Høiby, Niels

AU - Villa, Federica

AU - Pedeferri, Maria Pia

AU - Cappitelli, Francesca

N1 - Photochemistry and Photobiology © 2011 American Society for Photobiology.

PY - 2011/11

Y1 - 2011/11

N2 - 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. We tested the activity of photoactivated TiO 2 both as powder and as coating on planktonic and biofilm growth of opportunistic pathogen organism Pseudomonas aeruginosa. Photoactivated TiO 2 inhibited planktonic bacterial cells; however, photoactivated coating and powder do not produce any effect on bacterial biofilm. We concluded that sessile cells have increased resistance to photocatalytic TiO 2 than planktonic cells.

AB - 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. We tested the activity of photoactivated TiO 2 both as powder and as coating on planktonic and biofilm growth of opportunistic pathogen organism Pseudomonas aeruginosa. Photoactivated TiO 2 inhibited planktonic bacterial cells; however, photoactivated coating and powder do not produce any effect on bacterial biofilm. We concluded that sessile cells have increased resistance to photocatalytic TiO 2 than planktonic cells.

U2 - 10.1111/j.1751-1097.2011.00972.x

DO - 10.1111/j.1751-1097.2011.00972.x

M3 - Journal article

C2 - 21790617

SN - 0031-8655

JO - Photochemistry and Photobiology

JF - Photochemistry and Photobiology

ER -