Objective: The bactericidal methods often apply chemical agents to disinfect pathogens, however, these chemicals may also cause environmental pollution, and health hazards in animals and humans. Recently, photocatalytic antimicrobial techniques using UV/TiO2 have been proposed, because they do not form dangerous compounds and present high efficiency disinfection. Therefore in this study, the photocatalytic bactericidal effect of TiO2 thin film was investigated on representatives of two main groups of pathogenic bacteria. Materials and Methods: Bacterial samples of Escherichia coli and Staphylococcus aureus diluted with sterilized distilled H2O were added onto the surface of each TiO2 coated glass. One uncoated glass slide was used as a negative control. The bacterial solutions were then irradiated with ultraviolet light at room temperature for 60 min. This solution was pour plated onto nutrient agar medium and incubated for 24 h in order to determine the number of viable cells in terms of colony-forming units (CFU). Results: Before exposure to UV viable cell number for E.coli and St. aureus suspension was 1.4  105 and 2.1  106 CFU/ml respectively. However after 1 h UV exposure the survival ratio in 150 microliter of E.coli on slide without TiO2 decreased to 65 CFU/ml but in slide with TiO2 decline was much more (48 CFU/ml).Viable cell enumeration for St. aureus was also performed and results indicated double difference between slides with and without TiO2. Conclusion: This study show that in comparison, inhibition rate of TiO2 thin film against E. coli and St. aureus as indicator bacteria was not much significant. However results indicate that photocatalytic inactivation with TiO2 thin film has the potential for use as a new tool for protection.

Keywords