Notice of RetractionDisinfection Using UVA Light on Glass Surfaces with or without Titanium Dioxide Coating

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.

The presenting author of this paper has the option to appeal this decision by contacting TPII@ieee.org.

Disinfection of surfaces is necessary in biological laboratories and medical facilities to reduce the number of bacteria. Ultraviolet light irradiation is a conventional method for sterilization. Ultraviolet C (UVC, 100 nm -280 nm) has high energy per photon but inadequate ability in penetration. Many studies suggested that when the surfaces were coated with titanium dioxide (TiO₂), ultraviolet A (UVA, 315 nm -400nm) was able to destroy bacteria effectively in the presence of water and oxygen. In the present study, the ability of TiO₂-coated surfaces in bacterial inactivation was investigated in an environment under standard temperature and humidity conditions (JIS Z 8703:1983). Glass surfaces with and without TiO₂ coating were smeared with Escherichia coli and illuminated from above (distance 20 mm) using high-power UV LED array (optical power output 230mW, peak wavelength 375 nm) for 20 minutes. Disinfection was successful in both coated and uncoated glass surfaces. No significant difference was found, which indicates that (1) UVA is able to destroy bacteria and (2) surfaces coated with TiO₂ are not superior to uncoated surfaces in the absence of water.