A Low-Cost Way to Decontaminate PPE Equipment

Widely used materials available in hardware stores, such as the ones shown here, can be combined with ultraviolet light found in closed research laboratories for inexpensive decontamination of personal protective equipment, say UD researchers. Credit: Photo by Evan Krape

As the weather gets cooler and people engage in indoor activities, the number of new coronaviruses increases (COVID-19Cases reported in the United States are increasing. This reflects the COVID-19 activity already being seen in Europe and elsewhere in the world.

In the meantime, problems in the supply chain are likely to result in limited supplies of respirators with filters, such as B. N95 masks. However, strategies to decontaminate personal protective equipment (PPE) remain unsolved in many hospitals with limited resources, both in the US and abroad.

Researchers at the University of Delaware, led by biomedical engineer Jason Gleghorn, have developed a system for decontaminating N95 masks using standard materials available in any hardware store, combined with UV-C (UV-C) light that is in Research laboratories with shutters can be found.

The method developed by UD offers decontamination comparable to more expensive methods at an affordable material cost of around 50 USD.

“We focused on economical science – how to decontaminate PPE in a very simple way that is easily scalable to high throughput so that it can be used by any healthcare facility worldwide,” said Gleghorn, associate professor of biomedical engineering at UD.

One simple solution

The project was inspired by Rachel Gilbert, a PhD student at the Gleghorn lab earlier this year, after learning that friends in the medical field wore the same N95 mask repeatedly day in and day out.

“This is of course better known today thanks to the media promotion on the subject, but it got me thinking,” said Gilbert.

She knew that UV-C light was routinely used to sterilize various materials and devices in research laboratories. She wondered if this technique could be used to decontaminate specialized masks, especially for front-line workers, in an inexpensive and scalable way.

UV germicidal radiation (UVGI) has been validated as an effective method for decontaminating masks between uses. UVGI systems are routinely used to decontaminate work environments and surgical suites, equipment, and ambulances, but not all healthcare facilities have access to these expensive commercial sterilization equipment. Even so, many UV-C lamps sit idle in biosafety cabinets in university laboratories and research facilities that may be empty due to restrictions due to the pandemic.

“It was important to be able to provide something on-site, unlike other methods that require UV systems for surgical procedures that cost tens of thousands of dollars, or ship masks for decontamination and rely on them to be on time come back, “added Gilbert.

When she discussed the idea with Gleghorn, a former firefighter and intensive care doctor, he immediately agreed. Gilbert called the effort a “large, collaborative teamwork” where many lab members read the literature together, find a solution, then go to the hardware store and set up at the height of the April pandemic while working from home.

It only took a couple of weeks to fix the problem and put the system together, but it took longer to ensure peer review.

“Peer review is an important part of the process. And while we wish it could go faster, there is a reason why innovations are rigorously scrutinized in the scientific community, ”said Gleghorn. “We have to make sure that the science is solid and that the methods we develop are safe for people.”

Use basic resources

Now more about how the method works.

Put two N95 masks next to each other and it will be impossible to tell which mask is contaminated with the novel coronavirus SARS-CoV-2 that causes the disease COVID-19. It’s not like dirt that you can see.

The system designed by the research team modifies common fluorescent lamps to hold the special UVGI lightbulbs and to supply them with electricity. This, in addition to special light placement arrangements and tin foil-covered cardboard for reflectors, creates multiple decontamination arrangements that can hit people. To confirm that the UV-C lights were effective, the researchers performed extensive mathematical calculations and models to ensure that the intensity of the UV radiation emitted by the reused light was correct and that the N95 masks were correct UV exposure received to decontaminate the masks.

The team developed freely downloadable building instructions in simple, easy-to-understand language with lots of pictures and made them freely available on the Gleghorn laboratory website. The instructions emphasize UV ​​safety and focus on healthcare use as special equipment such as a UV-C intensity meter is required. They also include precautions for measuring UV-C intensity to ensure that the system is providing the correct level of UV intensity for sufficient time to decontaminate.

The detailed setup instructions also include detailed information such as: B. how far apart the masks are to achieve maximum effectiveness. This is important because too close a placement can create shadows that prevent extensive UV-C decontamination.

It is important to note that this is not a home device.

“You need suitable personal protective equipment to be able to work with UV light, which can lead to disruptions DNA and raise safety concerns, ”Gilbert said.

However, this disturbing feature makes the UV-C light precisely useful for decontaminating PPE.

“The UV light causes the virus DNA to break down and become ineffective,” explained Gleghorn.

“The virus – that little prickly thing you’ve seen by now – may still be with you, but the genetic material inside is getting fragmented and doesn’t have the proper machinery to replicate itself.”

The research team hired Kim Bothi, former global technical director and now executive director of the UD Center for Hybrid, Active and Responsive Materials, to think about how the project could be scaled up. She, too, has experience in fire fighting and paramedics, not to mention expertise in integrating new ideas into a global spectrum.

Bothi used their global expertise and relationships to recruit volunteers around the world and translate the building instructions into multiple languages ​​with regional information. So far the instructions have been translated into French, Spanish, Portuguese, Russian and German. So far, users in 52 countries have accessed the blueprints over 1,060 times.

She is also working on a policy brief to share the research team’s methodology with the Delaware congressional delegation. In addition, Bothi shares information with colleagues who work with the Kenya Medical Research Institute and other non-governmental organizations around the world.

“Like any other technology or innovation, our standard decontamination method will only have an impact if people are aware of it,” she said.

Researchers acknowledge that reusing masks is not ideal, but also recognize that not all hospitals or other patient care facilities are equipped with enough PPE to meet needs during a crisis. Therefore, first responders may need to reuse masks in emergency situations.

This includes doctors, nurses, and emergency personnel, but also extends to behind-the-scenes workers who may clean, disinfect, or prepare rooms for patient care. Beyond hospitals, PPE is worn in residential facilities and rural clinics around the world that may have limited access to resources.

In a perfect world, Bothi would like academic and research institutions to work hand in hand with hospital systems in order to jointly use these standard systems where they are needed.

Kenya, for example, is a country in sub-Saharan Africa that has a fairly robust health system. Yet the country is still facing an incredible shortage of PPE, just like here in the United States.

“The bigger advantage will be to transfer this to other regions of the world where they don’t have the resources,” said Gleghorn.

The team published their method in an article in the journal Global Health: Science and Practice.

Reference: “Reuse of Masks in the COVID-19 Pandemic: Creating an Inexpensive and Scalable UV System to Filter Decontamination of Respirators” by Rachel M. Gilbert, Michael J. Donzanti, Daniel J. Minahan, Jasmine Shirazi, Christine L. . Hatem and Brielle Hayward-Piatkovskyi, Allyson M. Dang, Katherine M. Nelson, Kimberly L. Bothi and Jason P. Gleghorn, October 2, 2020, Global Health: Science and Practice.
DOI: 10.9745 / GHSP-D-20-00218

Other co-authors of the work are Gleghorn’s multidisciplinary team of doctoral students and employees, whose fields of study range from biomedical engineering through biosciences, chemistry and biochemistry to chemical and biomolecular engineering. In addition to Gilbert (the newspaper’s lead author), Allyson M. Dang, Michael J. Donzati, Christine L. Hatem, Brielle Hayward-Piatkovskyi, Daniel J. Minahan, Katherine M. Nelson and Jasmine Shirazi belong to the team of doctoral students.