Comparative Study of Blue Light with Ultraviolet (UVC) Radiations on SARS-CoV-2 Virus
The ongoing coronavirus pandemic requires more effective disinfection methods. The disinfection using ultraviolet light (UV), especially longer UVCs such as 254 nm, 270/280 nm have been proved to have virucidal properties, but its adverse effects on human skin and eyes limit its use to enclosed unoccupied spaces. Several studies conducted the in past have shown the effectiveness of blue light (405nm) against bacteria and fungi, but the virucidal property of 405nm has largely been unexplored. Based on previous studies, visible light mediates inactivation by absorbing the porphyrins and reacting with oxygen to produce reactive oxygen species (ROS). This causes oxidative damage to biomolecules such as protein, lipids, and nucleic acids, essential constituents of any virus. The virucidal potential of visible light has been speculated because the virus lacks porphyrins. This study demonstrated porphyrin independent viral inactivation and a comparative analysis of the effectiveness of 405nm against other UVC wavelengths. The beta coronavirus 1 (strain OC43) was treated against 405nm, 270/280nm, 254nm, and 222nm, and its efficacy was determined using median tissue culture infectious dose, i.e., TCID50. The results support the disinfection potential of visible light technology by providing a quantitative effect that can serve as a basic groundwork for future visible light inactivation technologies. In the future, blue light technology usage can be widened to hospitals, public places, aircraft cabins, and/or infectious laboratories to inactivate SARS-CoV-2.