Bactericidal Effects of Thermal-Sprayed Nanostructured TiO2 on Pseudomonas Aeruginosa

Titanium dioxide (TiO2) has been shown to exhibit photocatalytic bactericidal activity. This preliminary study focuses on examining the photocatalytic activity of high velocity oxy-fuel (HVOF) sprayed and flame sprayed (FS) nano-structured TiO2 coatings to kill Pseudomonas aeruginosa (PAK). The HVOF TiO2 coatings were lightly polished and sterilized in preparation for treatment. Plates of PAK were grown, and then suspended in a phosphate buffer saline (PBS) solution. The concentration of bacteria used was regulated by a photospectrometer, which measured the amount of light absorbed by the bacteria-filled solution. This solution was diluted and pipetted onto the prepared sample, then exposed to light. In preliminary tests it was found that, when exposed to white light, 10% of the bacteria were killed after 60 minutes. Exposure to long wavelength (360 nm) UV radiation killed 25% of the bacteria after 60 minutes. These results show that thermal-sprayed nanostructured TiO2 exhibit photocatalytic bactericidal activity.