Effectiveness of near-UVA in SARS-CoV-2 inactivation

Abstract

This experimental study aimed to determine the activity of a near-UVA (405nm) LED ceiling system against the SARS-CoV-2 virus. The ceiling system comprised 17 near-UVA LED lights with a radiant power of 1.1 Watt/each centred at 405 nm wavelength. A 96multiwell plate, fixed to a wooden base, was inoculated with suspensions of VERO E6 cell cultures infected with SARS-CoV-2 virus and irradiated at a distance of 40 cm with a dose of 20.2 J/cm 2 for 120 minutes. The collected suspensions were transferred to VERO cell culture plates and incubated for 3 days. The maximum measurable log reduction obtained, starting from a concentration of 10 7.2 TCID50/mL, was 3.0 log 10 and indicated inhibition of SARS-CoV-2 replication by the near-UVA LED ceiling system. Near-UVA light at a 405-nm wavelength is emerging as a potential alternative treatment for localized

Efficacy of Violet-Blue (405 nm) LED Lamps for Disinfection of High-Environmental-Contact Surfaces in Healthcare Facilities: Leading to the Inactivation of Microorganisms and Reduction of MRSA Contamination

“…As a positive control, parallel areas adjacent to The CT and CTS plates contain four neutralising agents to inactivate chemical disinfectants left over from manual cleaning: the combination of lecithin, polysorbate 80 and L-histidine neutralises aldehydes and phenolic compounds; the combination of lecithin and polysorbate 80 neutralises quaternary ammonium compounds, polysorbate 80 neutralises hexachlorophene and mercury derivatives, sodium thiosulphate neutralises halogen compounds and lecithin neutralises chlorhexidine [32]. RODAC plates were pressed on each surface for 10 s and then incubated for 48 h at 37 • C (CT) or five days at room temperature (CTS) [26].…”

“…For example, violet-blue light in the range of 405-470 nm has shown promising results in disinfecting surfaces and air [24]. This light has been found to have antimicrobial properties that can effectively inactivate a wide range of microorganisms, including bacteria, viruses and fungi [25,26]. The mechanism of action of violet-blue light is based on the production of reactive oxygen species (ROS), which can damage the cellular components of microorganisms and lead to their cellular death [27].…”