A laboratory-based study examining the properties of silk fabric to evaluate its potential as a protective barrier for personal protective equipment and as a functional material for face coverings during the COVID-19 pandemic

Abstract

The worldwide shortage of single-use N95 respirators and surgical masks due to the COVID-19 pandemic has forced many health care personnel to use their existing equipment for as long as possible. In many cases, workers cover respirators with available masks in an attempt to extend their effectiveness against the virus. Due to low mask supplies, many people instead are using face coverings improvised from common fabrics. Our goal was to determine what fabrics would be most effective in both practices. Under laboratory conditions, we examined the hydrophobicity of fabrics (cotton, polyester, silk), as measured by their resistance to the penetration of small and aerosolized water droplets, an important transmission avenue for the virus causing COVID-19. We also examined the breathability of these fabrics and their ability to maintain hydrophobicity despite undergoing repeated cleaning. Laboratory-based tests were conducted when fabrics were fashioned as an overlaying barrier for respirators and when constructed as face coverings. When used as material in these two situations, silk was more effective at impeding the penetration and absorption of droplets due to its greater hydrophobicity relative to other tested fabrics. We found that silk face coverings repelled droplets in spray tests as well as disposable single-use surgical masks, and silk face coverings have the added advantage over masks such that they can be sterilized for immediate reuse. We show that silk is a hydrophobic barrier to droplets, can be more breathable than other fabrics that trap humidity, and are re-useable via cleaning. We suggest that silk can serve as an effective material for making hydrophobic barriers that protect respirators, and silk can now be tested under clinical conditions to verify its efficacy for this function. Although respirators are still the most appropriate form of protection, silk face coverings possess properties that make them capable of repelling droplets.

The effect of N95 and surgical masks on mucociliary clearance function and sinonasal complaints

“…During the use of masks, air passes through a narrow passage and breathing pressure, breathing resistance and breathing quality are affected [ 14 ]. Therefore, besides the filtration capacity, the breathability of the masks is also crucial [ 15 ]. It has been suggested that breathability will not be altered if the flow rate of the air passing through the mask is above 85 L/min [ 16 ].…”

Historical Evolution and Filtering Characteristics of Masks and Respirators in Dentistry in the Context of COVID-19

“…[ 30 ] Silk, like an FFP2 respirator, has properties that may provide a protective barrier against respiratory infection particles such as SARS-CoV-2, but its effectiveness for the respective function remains to be evaluated. [ 46 ] Dentists are the health professionals most at risk for exposure to respiratory infections, and a fabric mask would not provide the necessary protection in a clinical setting. [ 45 47 ]…”

Uso de equipamento de proteção individual pelos profissionais da saúde e a população em geral durante a Pandemia da COVID-19/ Use of personal protection equipment by health professionals and the general population during the COVID-19 novel

“…O uso de EPIs, desinfetantes e sanitizantes é de fundamental importância no combate à Covid-19 (PARLIN, 2020). Contudo, os profissionais da saúde, constantemente expostos a isso em sua prática assistencial, podem desenvolver lesões dermatológicas importantes (SALOMÉ e PONTES, 2020).…”