The PPE supply crisis is clearly not going away any time soon, prompting scientists working across the globe to find innovative solutions.
One of the most compelling and promising is an ultrathin, flexible membrane that attaches to surgical face masks. A key feature is that the membrane is ‘nanoporous,’ meaning that pore sizes range from 55 nm to no larger than 5 nm to ensure that airborne particles smaller than 300 nm are effectively filtered out. Importantly, the COVID-19 virus emits air particles as small as 65 to 125 nm. The membrane is also ‘hydrophobic’ according to study findings published in ACSNano journal, enabling virus droplets that typically accumulate on N95 face mask respirators roll or slide off (and potentially be repelled altogether). Net-net: the membrane is ‘self-cleaning.’ This self-cleaning feature addresses concerns that membrane-based filtering mechanisms allow particles to cake up or accumulate on the surface, subsequently blocking and limiting filtration and in turn, air flow.
The researchers (who are based at King Abdullah University of Science and Technology in Saudi Arabia [KAUST]) point out that while surgical N95 masks are considered most efficient for protecting healthcare workers, filtration efficiency for airborne particles smaller than 300 nm is only about 85%. So, reusable solutions such as the one offered by the KAUST team not only address current surgical grade N95 shortages but also an important shortcoming. The team is currently working with commercial partners to optimize the mask’s breathability and filtration efficacy, according to the University blog.
Antimicrobial coating blocks 99.9% of viruses and bacteria
Meanwhile, University of Toronto’s molecular genetics lab researchers report that an antimicrobial coating developed by British Columbian i3Biomedical Inc deactivates >99% of SARS-CoV-2 within minutes. This feature, which is found on i3Biomedical’s TrioMed Active Mask type IIR surgical mask, addresses healthcare workers’ risk for acquiring COVID-19 infections by touching or adjusting their face masks. (Findings reported in the May 1 Lancet Microbe Journal suggest that the virus remains infectious on mask surfaces for up to a week.) The masks are also effective against methicillin-resistant staphylococcus aureus, vancomycin-resistant enterococci, and influenza. The company reports that both viral and bacterial filtration efficiencies exceed 99.9%.
Space-age solutions offered by NASA
NASA’s Glenn Research Center scientists have partnered with University Hospitals Cleveland to develop PPE contamination strategies that are effective on earth and in space. One method uses atomic oxygen, single oxygen atoms that are pervasive in ‘low-Earth orbit (earth-centered orbit with an altitude of 1,200 miles or less) and remove organic materials that are not easily removed or cleared by other methods. Atomic oxygen can also be created by heating ozone in a container; as it decomposes, it is able to destroy viruses. NASA reports that early testing shows N95 masks that were placed in decontamination cycles filtered infectious-like particles after 20 minutes. Continued testing will determine minimum exposure time and ozone concentrations needed to kills SARS-CoV-2.
Finally, NASA and partners are exploring the utility of peracetic acid (a chemical disinfectant used in healthcare, food, and water treatment), which has been shown to kill 99.99% of viruses as well as highly-resistant bacterial spores from N95 masks without affecting filtration, structural integrity, or strap elasticity. Tests are being conducted at the Department of Veteran Affairs, Case Western Reserve University, and University Hospitals. Over the next few weeks, the researchers will be evaluating the number of optimal disinfection cycles needed to decontaminate large amounts of PPE without impacting overall performance. Ironically, the COVID-19 pandemic might have revealed a new frontier, albeit on earth.
Flexible Nanoporous Template for the Design and Development of Reusable Anti-COVID-19 Hydrophobic Face Masks ACS Nano. Membrane makeover makes face mask reusable. KAUST Discovery. U of T tests show Canadian-made mask deactivates 99% of SARS-CoV-2 virus. U of T News. I3 Biomedical TrioMed. I3biomedical.com Stability of SARS-CoV-2 in different environmental conditions. Lancet. NASA, University Hospitals Join Forces in Response to COVID-19. National Aeronautics and Space Administration.