Structure and photocatalytic influence of N-doping ATO nano-tubes on antibacterial activity toward Escherichia coli

Abstract

The photocatalytic antibacterial properties of anodic titanium oxide (ATO) nanotubes in the anatase structure derived from annealing at 450°C or 550°C or N-doping treatment were tested on Escherichia coli under UV-A, visible light illumi-nation, and dark conditions. Under UV-A illumination and dark conditions, in most cases, E. coli cultures containing ATO nanotubes of different treatments showed either no or slight differences in their growth from the cultures without ATO nanotubes. However, under visible light illumination, the growth of E. coli was inhibited in cultures containing ATO nanotubes. Among the three forms of ATO nanotubes, N-doped ATO nanotubes had the strongest antibacterial activ-ity. While the antibacterial activities of both the annealed and the N-doped ATO nanotubes increased positively correlated to the increase in their total surface area.