Impacts of Surface Characteristics and Dew Point on the Blue-Light (BL₄₀₅) 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 (BL₄₀₅) 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 BL₄₀₅ 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 BL₄₀₅ on surfaces. This research utilizes three surfaces: ceramic, PTFE, and stainless steel. The efficacy of BL₄₀₅ 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 BL₄₀₅ inactivation efficacy was determined. This research is the first to study the effects of the dew point on the virucidal effectiveness of BL₄₀₅ 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 BL₄₀₅ inactivation and viral degradation for the experiments and controls, respectively.