Disinfection Properties of Conventional White LED Illumination and Their Potential Increase by Violet LEDs for Applications in Medical and Domestic Environments

Abstract

The antimicrobial impact of visible violet and blue light has been known for more than a century but hardly been applied for purposeful pathogen reduction or prevention. The disinfecting properties of wide-spread warm-white and cool-white light emitting diodes (LEDs) are investigated by irradiation of staphylococci with different LEDs and varying doses. Additionally, the combination of a white and a violet LED illumination is examined. Both white LEDs exhibit an antimicrobial effect, which seems to be dominated by the blue parts of the LED emissions. Unfortunately, the antimicrobial effect is weak in realistic illumination applications. Additional violet LEDs can significantly enhance this impact without a large change in human color perception. This allows reasonable applications in certain medical and domestic environments without endangering humans.

High Intensity Violet Light (405 nm) Inactivates Coronaviruses in Phosphate Buffered Saline (PBS) and on Surfaces

“…A 405 nm irradiation could be applied alone, as suggested by Maclean et al [56] or it could be combined with a white illumination [57], even in the presence of people. In the presented experiments, a 4 log reduction was achieved within half an hour, but this is a high intensity irradiation, which is difficult to achieve for larger volumes or areas.…”

Photoinactivation of Staphylococcus carnosus on Surfaces by Irradiation with Blue and Violet Light

“…• Violet LEDs are applied together with white LEDs to achieve a sufficient color rendering index and the required illumination, which has already been attempted in other investigations [21]. This would ensure a continuous irradiation and a sufficient reduction of pathogens.…”