Impacts of Surface Characteristics and Dew Point on the Blue-Light (BL(405)) Inactivation of Viruses

The increased prevalence of multidrug-resistant organisms (MDROs), healthcare associated infections (HAIs), and the recent COVID-19 pandemic has caused the photoinactivation industry to explore alternative wavelengths. Blue light (BL(405)) has gained significant interest as it is much less harmful to the skin and eyes than traditional germicidal wavelengths; therefore, in theory, it can be used continuously with human exposure. At present, the viricidal effects of BL(405) are largely unknown as the literature predominately addresses bacterial disinfection performed with this wavelength. This work provides novel findings to the industry, reporting on the virucidal effects of BL(405) on surfaces. This research utilizes three surfaces: ceramic, PTFE, and stainless steel. The efficacy of BL(405) inactivation varied by surface type, which was due to surface characteristics, such as the contact angle, porosity, zeta potential, and reflectivity. Additionally, the effect of the dew point on BL(405) inactivation efficacy was determined. This research is the first to study the effects of the dew point on the virucidal effectiveness of BL(405) surface inactivation. The effects of the dew point were significant for all surfaces and the control experiments. The high-dew-point conditions (18 °C) yielded higher levels of BL(405) inactivation and viral degradation for the experiments and controls, respectively.