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. 2021 Jul 26;16(7):e0241734.
doi: 10.1371/journal.pone.0241734. eCollection 2021.

UV decontamination of personal protective equipment with idle laboratory biosafety cabinets during the COVID-19 pandemic

Davis T Weaver  1 , Benjamin D McElvany  2 , Vishhvaan Gopalakrishnan  1 , Kyle J Card  1   3 , Dena Crozier  1 , Andrew Dhawan  1   4 , Mina N Dinh  1 , Emily Dolson  1 , Nathan Farrokhian  1 , Masahiro Hitomi  1 , Emily Ho  1 , Tanush Jagdish  5 , Eshan S King  1 , Jennifer L Cadnum  6 , Curtis J Donskey  6 , Nikhil Krishnan  1 , Gleb Kuzmin  1 , Ju Li  7 , Jeff Maltas  8 , Jinhan Mo  9 , Julia Pelesko  1 , Jessica A Scarborough  1 , Geoff Sedor  1 , Enze Tian  7 , Gary C An  2 , Sean A Diehl  2 , Jacob G Scott  1
Affiliations

UV decontamination of personal protective equipment with idle laboratory biosafety cabinets during the COVID-19 pandemic

Davis T Weaver et al. PLoS One. .

Abstract

Personal protective equipment (PPE) is crucially important to the safety of both patients and medical personnel, particularly in the event of an infectious pandemic. As the incidence of Coronavirus Disease 2019 (COVID-19) increases exponentially in the United States and many parts of the world, healthcare provider demand for these necessities is currently outpacing supply. In the midst of the current pandemic, there has been a concerted effort to identify viable ways to conserve PPE, including decontamination after use. In this study, we outline a procedure by which PPE may be decontaminated using ultraviolet (UV) radiation in biosafety cabinets (BSCs), a common element of many academic, public health, and hospital laboratories. According to the literature, effective decontamination of N95 respirator masks or surgical masks requires UV-C doses of greater than 1 Jcm-2, which was achieved after 4.3 hours per side when placing the N95 at the bottom of the BSCs tested in this study. We then demonstrated complete inactivation of the human coronavirus NL63 on N95 mask material after 15 minutes of UV-C exposure at 61 cm (232 μWcm-2). Our results provide support to healthcare organizations looking for methods to extend their reserves of PPE.

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Conflict of interest statement

JGS, the senior author, has, subsequent to this research, led a related patent for a UV decontamination device (PCT/US2021/022771, led march 17, 2021: \Decontam-ination System"). This does not alter our adherence to all PLOS ONE policies on sharing data and materials, and in fact, the patent was a reaction to this work, and so therefore was entirely performed subsequently to this research. Further, beyond the fact that the patent is for a UV-C decontamination chamber, it has little to do with this research.

Figures

Fig 1
Fig 1. UV radiation in each sector of each BSC as measured with a UV meter.
Each of the nine sections per BSC shows the UV radiation measured in the section. Numbers indicate UV radiation measured in each section.
Fig 2
Fig 2. UV radiation in each sector of BSC 1 at three different heights.
Each of the nine sections per elevation shows the UV radiation measured in the section. Numbers indicate UV radiation measured in each location with the UV meter.
Fig 3
Fig 3. Time to decontaminating dose with respect to distance from UV lamp for face-shield and FFR decontaminating doses.
An inverse square function was fit to UV fluence data from hood 1 at various heights for the left, center, and right-hand sections of the BSC, as visualized in Fig 2, and used to calculate time for decontaminating dose per side at target doses of 1 J cm−2 and 60 mJ cm−2 This approximate inverse square relation can be exploited to deliver high doses of UV within a BSC in a reasonable amount of time by positioning PPE close to the UV lamp.
Fig 4
Fig 4. Infectious units recovered in UV exposed versus control masks strips.
20 minutes of UV-C radiation in a BSC was sufficient to achieve more than a 3 log reduction in viral recovery of the NL63 coronavirus.
See this image and copyright information in PMC

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