Indian-American bioengineer develops reusable scuba-gear masks to protect health-care worker

Manu Prakash, associate professor of bioengineering at Stanford University. (Photo:

Manu Prakash runs a lab at Stanford University that specializes in what he calls “frugal science,” solving global health problems with nontraditional, cost-efficient tools. His lab developed Foldscope, a paper microscope that costs $1.75 and is used across the world for scientific education and research.

Prakash, a bioengineer, turned his sights to the global coronavirus pandemic when it became apparent that personal protective equipment was essential and in short supply.

In mid-March, Prakash had just returned from a work trip in France when he found himself coughing, short of breath and burning with fever. He ended up at Stanford University Medical Center, where he tested negative for covid-19, the disease caused by the novel coronavirus, but still went home to quarantine and recover.

Prakash, 40, locked himself in with everything he brought home from that trip – including his snorkel mask. He thought of his time at the hospital, when doctors and nurses threw away their protective equipment after each check-in. Could he make reusable protective equipment from his snorkel mask that could be used by doctors and nurses if hospitals run out?

That question turned into a potential solution called Pneumask, which costs about $40 to make. It combines an off-the-shelf, full-face scuba mask and a medical-grade filter. It works by attaching to the mask a filter commonly found in a hospital.

In two weeks, Prakash and about 10 Stanford students conducted research on the effectiveness of the Pneumask design and submitted their findings to the Food and Drug Administration.

“Nothing about this is normal,” Prakash said, adding that they’ve never before submitted research to the FDA in such a short period. “There’s nothing normal about what’s happening around the world right now. I wish we had more time. I wish we were not here.”

The FDA approved their product as a face shield or surgical mask – not a respirator – so they could ship the masks to health-care workers as soon as possible. Respirators are designed to seal to the face and protect from airborne particles, including viruses, while surgical masks offer less protection and are a barrier to larger substances such as saliva.

The FDA said it needed more information to decide whether the device can be a reusable substitute to N95 respirators, and Prakash said such approval would take time.

This week, the group is shipping 1,500 masks free to clinicians in Alabama, California, Florida, Illinois and New York. It’s planning to send an additional 7,000 Pneumasks in the coming weeks.

Prakash’s team is publishing its work so health-care professionals can be informed about how best to use the Pneumask and how to sterilize it between uses.

The goal is that Pneumask can be used if hospitals run out of masks or face shields. The FDA has said it does not object to health-care professionals improvising protective equipment when alternatives are unavailable.

There are reports of doctors in Spain, Belgium and elsewhere around the world using full-face scuba masks to protect against the novel coronavirus. Prakash hopes his lab can support these efforts to develop reusable equipment.

“My desire would be that nobody would have to use anything like this, but, on the other hand, there are no good solutions out there,” Prakash said.

Prakash has formed an international coalition of medical experts and clinicians, with backing and technical support from companies such as Boston Scientific and Medtronic. With coordination through the coalition, doctors in Chile and France are working to use full-faced scuba masks as acceptable alternatives for respirators in hospitals.

The parts in a Pneumask require one custom piece connecting the mask to the filter. Prakash created the piece using medical-grade equipment. He said he knows of people who have made the piece from a 3-D printer, but that method might not ensure an airtight seal.

Roberto Miki, an orthopedic surgeon who runs a private practice in Miami, is one of the doctors helping Prakash in his coalition. Before he knew about the coalition, Miki fashioned his own scuba mask solution and posted it on YouTube. Now, Miki said, he’s using his own funds to buy and distribute masks using the Pneumask design for medical staffers and first-responders in the Miami area.

There is a need for reusable alternatives to N95 masks and other disposable equipment, Miki said, because the supply chains won’t be able to support the demand for masks as the pandemic continues and more people are hospitalized.

“A lot of light needs to be shed on this project,” he added. “There’s a [coronavirus] peak that’s coming and if this project doesn’t get off the launchpad quick enough, we’re going to miss part of that peak. We’re going to miss saving some people.”

No matter how many masks they make, the Pneumasks will remain a limited resource, Prakash said. There are only so many full-face scuba masks in the world. The goal is to create 50,000 to deliver, and the group has made about 1,700. Prakash said his plan will rely on hospitals sending back masks when they no longer need the extra support. If it works, the masks will be able to follow the spread of the virus, aiding medical professionals who need help the most.

When the pandemic is under control, Prakash said, there will be a “remarkable amount of innovation” born out of the solutions people are piecing together now under pressure.

“What this pandemic has done is truly expose the underbelly of weaknesses that we have in our protection for health-care workers,” he added.

The Pneumask is one of many projects underway in Prakash’s lab to help health-care workers combat covid-19. In a separate effort, Stanford students are working on a way to create filters that compare to N95 respirators by using cotton-candy machines, or a similar rotary device, and Styrofoam.

“You have to look at an object with a different eye, and you’ll see a solution in it,” Prakash said.



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