Photocatalytic effects of TiO2/Fe thin film irradiated with visible light on cellular surface ultrastructure and genomic DNA of bacteria

TiO2/Fe thin film is thin film modified by metal (Fe) plasma ion implantation. In our previous work, it has been demonstrated to have antimicrobial activity after being irradiated with visible light. However, the mechanism of its antimicrobial activity has not been well known yet. In this study, the effects of TiO2/Fe thin film irradiated with visible light on the cellular morphology and DNA of the Erwinia carotovora subsp. carotovora ZL1, an important soft rot bacterium of vegetable and ornamental crops were examined. Scanning electron microscopic studies revealed that abnormal ultrastructures were observed on the surface of E. carotovora subsp. carotovora ZL1 cells treated with TiO2/Fe thin films irradiated with visible light for 60 min. Based on the gel electrophoresis analysis, the genomic DNA of E. carotovora subsp. carotovora ZL1 cells treated with TiO2/Fe thin films under visible light irradiation was also affected. The results suggest that TiO2/Fe thin film irradiated with visible light has the potential to disinfect of plant- or public health-concerned pathogens. (c) 2006 Elsevier B.V. All rights reserved.