key: cord-289778-x938errh
authors: Lee, J.; Bong, C.; Bae, P. K.; Abafog, A. T.; Baek, S. H.; Shin, Y.-B.; Park, M. S.; Park, S.
title: Fast and easy disinfection of coronavirus-contaminated face masks using ozone gas produced by a dielectric barrier discharge plasma generator
date: 2020-05-01
journal: nan
DOI: 10.1101/2020.04.26.20080317
sha: 
doc_id: 289778
cord_uid: x938errh

Face masks are one of the currently available options for preventing the transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which has caused the 2019 pandemic. However, with the increasing demand for protection, face masks are becoming limited in stock, and the concerned individuals and healthcare workers from many countries are now facing the issue of the reuse of potentially contaminated masks. Although various technologies already exist for the sterilization of medical equipment, most of them are not applicable for eliminating virus from face masks. Thus, there is an urgent need to develop a fast and easy method of disinfecting contaminated face masks. In this study, using a human coronavirus (HCoV-229E) as a surrogate for SARS-CoV-2 contamination on face masks, we show that the virus loses its infectivity to a human cell line (MRC-5) when exposed for a short period of time (1 min) to ozone gas produced by a dielectric barrier discharge plasma generator. Scanning electron microscopy and particulate filtration efficiency (PFE) tests revealed that there was no structural or functional deterioration observed in the face masks even after they underwent excessive exposure to ozone (five 1-minute exposures). Interestingly, for face masks exposed to ozone gas for 5 min, the amplification of HCoV-229E RNA by reverse transcription polymerase chain reaction suggested a loss of infectivity under the effect of ozone, primarily owing to the damage caused to viral envelopes or envelope proteins. Ozone gas is a strong oxidizing agent with the ability to kill viruses on hard-to-reach surfaces, including the fabric structure of face masks. These results suggest that it may be possible to rapidly disinfect contaminated face masks using a plasma generator in a well-ventilated place.

. A schematic diagram describing the disinfection of a face mask contaminated by a disinfecting face masks contaminated with a coronavirus. Similar results were obtained for 117 face masks experimentally contaminated with either influenza A virus (H1N1) 10 (Table S1) or 118 Gram-positive bacteria Staphylococcus aureus (Table S2 and Figure S1) when exposed to 119 ozone gas. These results suggest that virus and bacteria on face masks can be inactivated by 120 ozone gas at a concentration of about 120 ppm within a short time (1-5 min). dried at room temperature for 15 min in a biosafety cabinet before exposed to ozone gas.

difference (p > 0.05; student's t-test) in the amount of amplifiable RNAs between the 142 unexposed and exposed masks, indicating that the short exposure may not fully degrade the 143 viral RNA (Table 2) . Similarly, the RNA of either H1N1 (Table S3 ) or S. aureus (Table S4) with and without exposure to ozone gas. To test if the exposure of face masks (Kleenguard®) to either plasma or ozone gas causes any 155 damage to their filter layer, uncontaminated face masks were exposed to ozone gas for 5 min 156 (five 1-minute exposures). We did not see any noticeable damage on the front and back side 157 of the face masks with eyes and under a light microscope, either (data not shown). Their inner 158 filter layer composed of polypropylene meltblown non-woven fabric was further examined 159 under a SEM. As shown in Figure 2 , there was no detectable structural damage caused to the 160 filter layer of the exposed face masks. The result showed that the repeated exposures (5 times) 161 of face masks to ozone gas did cause structural damage to the face masks.

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The copyright holder for this preprint this version posted May 1, 2020. 98.6 ± 0.5 (n=6) a The lab is certified and registered as a testing lab by the ministry of food and drug safety (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted May 1, 2020. . https://doi.org/10. 1101 /2020 

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