Verification of inactivation effect of deep-ultraviolet LEDs on bacteria and viruses, and consideration of effective irradiation methods

Abstract

With the widespread of the novel coronavirus (SARS-CoV-2), the inactivation of bacteria and viruses using ultraviolet (UV) light has been reevaluated. However, there are many applications where the safety to the human body itself and inactivation effect itself are questioned, and there is a movement to review the UV-C guidelines (Global Lighting Association, Position Statement on Germicidal UV-C Irradiation UV-C SAFETY GUIDELINES, 2020). Since the Minamata Convention on Mercurybans the production of mercury in principle, deep-ultraviolet light-emitting diodes (UVC-LEDs) are now being used in place of mercury lamps. In this paper, we will discuss effective irradiation methods for the inactivation of pathogens on solid surfaces, the inactivation of pathogens in water, and the inactivation of viruses in aerosols using UVC-LED.

A Comprehensive Analysis of the UVC LEDs’ Applications and Decontamination Capability

“…The SLR's results demonstrate a concentration of studies [3,8,17,[21][22][23][28][29][30][31][32][33][34][35][36][37][38][39][40] in this scientific field. Of these studies, all found some level of decontamination effectiveness.…”

“…In terms of disinfection (at least three log-reduction), we have seven studies [3,24,[33][34][35][36][37][38] indicating it. Meanwhile, ten studies [8,17,21,23,[28][29][30][31][32]39] indicate elimination of biological indicators (sterilization) or growth inhibition. In terms of lower levels of decontamination effectiveness, only one study [22] discussed it.…”

“…For instance, Messina et al [28] found significant decontamination effectiveness of UVC LEDs on stethoscopes after 243 h. Finally, in terms of features, researchers defend UVC LEDs application by comparing decontamination with other methods, finding results like the percentages ranges with other decontamination methods such as 0.5% chlorhexidine [23], alcohol [28], or distilled water [40]. Researchers have also discussed UVC LEDs parameters, like exposure time, the distance from the UVC source, and surface characteristics [22,28,[31][32][33]. This discussion is crucial for quick reproducibility in the health context.…”

“…Due to the COVID-19 pandemic, there has been an increasing concern about air quality. COVID-19 spreads majorly via aerosols [32] emitted by infected persons. Actions like coughing, sneezing, and even talking may lead to infected aerosol released into the environment.…”

“…Researchers have been proposing strategies to decontaminate closed environments to deal with this issue in the literature. Muramoto et al [32] developed an air purifier that combines UVA/UVC-LEDs and a HEPA filter, a honeycomb ceramics filter, and a pre-filter. In this system, the LEDs are responsible for irradiating the surface of the HEPA filter to decontaminate microorganisms trapped in it.…”