Titanium dioxide (TiO₂) is a wide bandgap (~3.4 eV) semiconductor material which is commonly used as a photocatalyst and antibacterial material. UV illumination with energy similar to the bandgap is often needed to make the material active. It would be favorable for practical applications, if its action can also be activated under ambient. Recently, robust antibacterial action was demonstrated on ZnO nanoparticles under ambient illumination. In this study, we demonstrated robust antibacterial activity of TiO₂ nanoparticles induced by annealing under ambient illumination. It was found that the antibacterial activity could be significantly changed by tuning the annealing temperatures and using different crucibles containing the nanoparticles. Bacterium Escherichia coli was used as the model organism in the test. It was observed that although no significant antibacterial activity was observed on the starting material (untreated commercial TiO₂ nanoparticles), the activity increases significantly if the nanoparticles were annealed above 650 °C with crucible lined with copper foil. The survival rate of E. coli bacteria approaches to zero if the nanoparticles annealing temperature reaches 850 °C. Under optimized conditions, three different titania nanoparticle samples exhibited antibacterial activity under ambient illumination. This work sheds light on the development of ambient-active antibacterial coating and in particular, on the modification of any TiO₂ material to become ambient-active with a suitable treatment.

Date Published: 13 March 2015
PDF: 6 pages
Proc. SPIE 9364, Oxide-based Materials and Devices VI, 93641A (13 March 2015); doi: 10.1117/12.2078568

Published in SPIE Proceedings Vol. 9364:
Oxide-based Materials and Devices VI
Ferechteh H. Teherani; David C. Look; David J. Rogers, Editor(s)