Harmless Effects of Sterilizing 222-nm far-UV Radiation on Mouse Skin and Eye Tissues.

There is growing interest in using ultraviolet (UV) radiation for bactericidal and viral decontamination of air, surfaces and foods, a trend that is reinforced during the Covid-19 pandemic. For almost a century and a half, UVC and UVB radiations have been used extensively for non-thermal sterilization against various microbial pathogens by developing so-called ultraviolet germicidal irradiation (UVGI) disinfection treatments (1). Most previous applications have used UVC light emitted from broad spectrum 254-nm low-pressure mercury lamps, which, however, has undesirable, harmful effects on the skin and retina of mammals due to, among other things, biomolecule damage by mutagenic and carcinogenic bipyrimidine photoproducts. These include predominant cyclobutane pyrimidine dimers (CPDs) as well as lower amounts of pyrimidine (6-4) pyrimidone photoadducts (6-4PPs) and their secondary photo-induced Dewar valence isomers (2).