ABSTRACT
The Covid-19 epidemic has been the most consequential global health crisis since the era of the influenza pandemic of 1918 [1]. Due to its high spreading rate, the virus disseminated across the world in a very short time span, forcing the World Health Organization to declare Covid-19 a global pandemic after just 3 months from the first reported case in China. At the beginning of the pandemic, when no vaccines were available, people entrust their safety to very few devices such as personal protective equipment (face masks, shields, and gloves), lock-down, and social distancing. The lack of alternative and not conventional techniques to suppress the spread of airborne epidemics among humans has pushed the research to develop new antiviral devices. The SAVE-US project (Suppression of Airborne Viral Epidemic Spread by UV-Light Barriers) aims at developing and demonstrating an innovative antimicrobial device based on 222nm-radiation. As known from the literature, the UVC radiation (200-280 nm) is the most effective wavelength for the inactivation of viruses and bacteria, corresponding to the DNA and RNA absorption peaks, but may also be mutagenic. For this reason, UVC-light sterilization is commonly performed in the absence of living organisms. Radiation in the far-UVC, especially at 222 nm, has been recently investigated because it shows a good antimicrobial efficacy, tested already on both bacteria [2] and virus [3] models including coronavirus, with very limited risks to human health. The low risk is associated to the small penetration depth of 222 nm light (a few mum): the energy is absorbed by the superficial stratum corneum of the skin that contains dead cells, with negligible irradiation of the underlying live tissue [4]. We will present the first version of a new prototype of 222 nm-illuminator and some preliminary results on its characterization;the presented device will be used in successive in vitro and in vivo experiments with SARS-CoV-2 virus. The device embeds a far-UVC lamp emitting at 222 nm, optical filters, and the controlling electronics. We show results on the spatial homogeneity of the emission intensity and the dependence on the lamp-virus distance. We also report on the ozone production due to absorption of far-UVC light from molecular oxygen naturally present in the air in order to evaluate its safety for human being and to properly evaluate its photo-killing efficacy.Copyright © 2023
ABSTRACT
BACKGROUND: Prolonged face mask usage, a daily practice for the public due to the COVID-19 pandemic, creates high levels of humidity underneath the mask, which may cause unexpected skin concerns. OBJECTIVE: To investigate the impact of repeated mask usage on the face by comparing skin properties inside and outside of the mask-covered areas. METHODS: A double-blinded, randomized, split-face clinical study was conducted with 21 healthy female participants who wore face masks at least 6 h every day for 1 week, with one side of their face treated with a moisturizer three times daily. On day 8, after 5 h of wearing the mask, skin properties (sebum, hydration, and trans-epidermal water loss [TEWL]) were evaluated at 15, 60, and 120 min post-mask removal, followed by barrier disruption and recovery assessment. RESULTS: Mask usage weakened stratum corneum (SC) on facial skin compared to uncovered areas, including reduced SC hydration (p < 0.02 at 15 min) and increased TEWL in response to tape stripping challenge (p < 0.03 after stripping). In addition, sebum production also increased after mask removal (p < 0.01 at 15 min). Notably, a daily moisturizer mitigated these effects by increasing SC hydration (p < 0.001) and improving SC resilience against barrier disruption. CONCLUSION: Daily prolonged usage of a facial mask, essential due to the COVID-19 situation, generated a high-humidity microenvironment and led to compromised SC, which was revealed by a barrier challenge technique. Moreover, proper facial moisturization may help to maintain skin homeostasis and prevent the barrier impairment caused by repeated mask usage.
ABSTRACT
Far UV-C, informally defined as electromagnetic radiation with wavelengths between 200 and 230 nm, has characteristics that are well-suited to control of airborne pathogens. Specifically, Far UV-C has been shown to be highly effective for inactivation of airborne pathogens;yet this same radiation has minimal potential to cause damage to human skin and eye tissues. Critically, unlike UV-B, Far UV-C radiation does not substantially penetrate the dead cell layer of skin (stratum corneum) and does not reach germinative cells in the basal layer. Similarly, Far UV-C radiation does not substantially penetrate through corneal epithelium of the eye, thereby preventing exposure of germinative cells within the eye. The most common source of Far UV-C radiation is the krypton chloride excimer (KrCl*) lamp, which has a primary emission centered at 222 nm. Ozone production from KrCl* lamps is modest, such that control of indoor ozone from these systems can be accomplished easily using conventional ventilation systems. This set of characteristics offers the potential for Far UV-C devices to be used in occupied spaces, thereby allowing for improved effectiveness for inactivation of airborne pathogens, including those that are responsible for COVID-19.