Irradiation by a Combination of Different Peak-Wavelength Ultraviolet-Light Emitting Diodes Enhances the Inactivation of Influenza A Viruses

Abstract

Influenza A viruses (IAVs) pose a serious global threat to humans and their livestock. This study aimed to determine the ideal irradiation by ultraviolet-light emitting diodes (UV-LEDs) for IAV disinfection. We irradiated the IAV H1N1 subtype with 4.8 mJ/cm² UV using eight UV-LEDs [peak wavelengths (WL) = 365, 310, 300, 290, 280, 270, and 260 nm)] or a mercury low pressure (LP)-UV lamp (Peak WL = 254 nm). Inactivation was evaluated by the infection ratio of Madin-Darby canine kidney (MDCK) cells or chicken embryonated eggs. Irradiation by the 260 nm UV-LED showed the highest inactivation among all treatments. Because the irradiation-induced inactivation effects strongly correlated with damage to viral RNA, we calculated the correlation coefficient (<i>R</i>_AE) between the irradiant spectrum and absorption of viral RNA. The <i>R</i>_AE scores strongly correlated with the inactivation by the UV-LEDs and LP-UV lamp. To increase the <i>R</i>_AE score, we combined three different peak WL UV-LEDs (hybrid UV-LED). The hybrid UV-LED (<i>R</i>_AE = 86.3) significantly inactivated both H1N1 and H6N2 subtypes to a greater extent than 260 nm (<i>R</i>_AE = 68.6) or 270 nm (<i>R</i>_AE = 42.2) UV-LEDs. The <i>R</i>_AE score is an important factor for increasing the virucidal effects of UV-LED irradiation.