Reading time ( words)
NASA's Glenn Research Center and University Hospitals (UH) in Cleveland have collaborated to develop new methods and technologies for decontaminating personal protective equipment (PPE) for aerospace applications and for safeguarding the health of workers caring for patients with coronavirus (COVID-19).
The decontamination room at University Hospitals where N95 masks are disinfected using the peracetic acid method. Courtesy: University Hospitals
A team of researchers recently developed and tested two new approaches that could enable health care professionals to sanitize masks on-site and safely reuse them. These approaches also may be useful to the aerospace community when traditional sterilization techniques might not be available.
"NASA strives to ensure the technology we develop for space exploration and aeronautics is broadly available to benefit the public and the nation," said Glenn Center Director Marla Pérez-Davis, Ph.D. "If our technology can lend a hand in overcoming this crisis, we will do whatever we can to put it in the hands of those who need it."
Results of tests on both methods – atomic oxygen and peracetic acid – are promising. The atomic oxygen decontamination method currently is being evaluated and early results are favorable. The peracetic acid method has been proven to work for five cycles of decontamination, and the Food and Drug Administration is reviewing this method for an emergency use authorization.
"While we currently have sufficient PPE on hand to care for the patients we have in our facilities today, we need to proactively and prudently plan for potential future needs," said Dr. Daniel I. Simon, chief clinical and scientific officer at University Hospitals and president of UH Cleveland Medical Center. "This includes factoring in the potential for supply chain shortages due to COVID-19 surges in other states while also taking into account our need to restart non-emergent and elective services, which requires being mindful about current usage and putting in place go-forward conservation strategies. The opportunity to pool resources and quickly bring about PPE sterilization solutions for the benefit of our caregivers is truly remarkable."
Atomic Oxygen Method
Glenn research engineer Sharon Miller and physicist Bruce Banks of SAIC developed a process and hardware to decontaminate masks using atomic oxygen. Pervasive in low-Earth orbit, these single oxygen atoms can remove organic materials that can't easily be cleaned by other methods.
"On Earth, we create atomic oxygen by putting ozone (O3) in a chamber and heating it," Miller said. "As the ozone decomposes into atomic oxygen, it can kill organisms like viruses."
Further testing is needed to verify the method can be used to perform multiple decontamination cycles without damaging the PPE. Recent filtration tests performed at an independent testing laboratory showed N95 masks filter well and pass acceptance testing after 20 minutes of atomic oxygen treatment. In early May, NASA provided a prototype for UH to test on N95 masks. Early results confirm the method deactivates the virus, and continued testing will determine the minimum ozone concentration and exposure time needed for disinfection.
"Ozone diffuses easily through and around objects, which makes it promising for sterilizing inside an N95 mask filter or loosely stacked masks, and it could potentially sterilize without leaving a residue," said Banks, who supports Glenn's Environmental Effects and Coatings branch. "The process could be scaled up to treat multiple batches of PPE or made portable for small hospitals in rural areas. No liquid chemicals would be needed, just oxygen and nitrogen gas."
Peracetic Acid Method
Doctors Amrita John and Shine Raju, infectious disease and critical care physicians in the Department of Medicine at UH Cleveland Medical Center, are examining peracetic acid – a chemical disinfectant commonly used in the health care, food, and water treatment industries – as an option for decontaminating PPE.
"We have some exciting results," said Raju. "We found that the peracetic acid disinfection method is very effective in killing 99.9999% of viruses and even highly resistant bacterial spores from contaminated N95 masks without any detectable loss of filtration, structural integrity and strap elasticity for up to five decontamination cycles. We believe that the peracetic acid disinfection method is the fastest method of mass-decontamination of N95 respirators currently available."
The U.S. Department of Veterans Affairs, Case Western Reserve University, and Glenn are participants in this multi-institutional study.
"It has been amazing to collaborate with such a multidisciplinary group of researchers and practitioners to discover innovative ways to conserve PPE," said John. "As physicians and researchers, we aim to develop solutions that can work for the multitude of PPE categories as well as the variety of operational needs of a given hospital or health system. In some instances, there may be needs beyond the FDA-approved methods currently in place, and we want to ensure we are well-positioned to offer options for our patients and health care workers should circumstances arise."
Dr. Curtis Donskey, an infectious disease physician at the Louis Stokes Cleveland VA Medical Center, supervised the microbiology testing for the peracetic acid study.
"The disinfection system could provide a means for in-hospital decontamination of large amounts of PPE during the coronavirus pandemic," said Donskey. "Further testing is needed to determine if more than five decontamination cycles can be performed with no adverse effects on PPE performance and we aim to assess that over the next several weeks."
This collaboration was facilitated by UH Ventures, the innovation and commercialization arm of University Hospitals.
"We have been successfully leveraging relationships with health care, technology, and supply chain providers across the state to bring to fruition several innovations that have addressed caregiver needs during this pandemic," said Kipum Lee, managing director of the UH Ventures Innovation Center and co-lead of the alternative PPE strategy team. "We have been honored to join forces with the NASA team, as well as researchers at the VA and Case, to promote innovation discovery in this new frontier."