Steve Kirk is a charge nurse at St. Joseph's Hospital and Medical Center in Phoenix and he has to treat every patient he sees as a potential carrier of the novel coronavirus. That means wearing some sort of personal protective equipment, starting with a face mask.

A few weeks ago, he received a new mask, but it wasn't like the ones he had been using. This one was created by the hospital's Barrow Neurological Institute Innovation Center, with the aid of a 3D printer.

Now he's breathing easier.

"There's definitely a much better sense of protection," Kirk said. "I feel more comfortable in this mask than I do in the N95 mask."

The new masks are made out of 3D printed plastic and are rimmed with form-fitting silicone that helps the mask adhere to the face. The plastic part of the mask is designed to attach to a P100 respirator, the highest-rated filter for personal respiratory protection.

While N95 masks, commonly used among health care workers to control disease exposure, filter out at least 95% of particles, P100 masks filter out 99.97% of small particles, making them more effective.

And unlike N95 masks, which are in short supply and in high demand by hospitals across the country, the printed masks are reusable and can be worn for up to three months.

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After three months, the P100 filters get clogged and need to be replaced, but the rest of the mask is still viable. That makes them a more sustainable option for hospitals as they continue to battle a surge of new COVID-19 cases.

Michael Lawton, president and CEO of the institute, hopes that masks like this can help address dangerous personal protective equipment shortages that have beset hospitals since the outbreak of the pandemic.

"Once you have enough and you've outfitted your team, you're good for a three-month period which, hopefully that would cover the full extent of the surge," he said. "After three months, the filter gets kind of clogged."

New masks fit better

Masks made by the Innovation Center are being given out to health care workers on the front lines at St. Joseph's Hospital.

The center is now filled with the clatter and beeping of 3D printers in full production mode, all 12 of them pumping out more masks. Lawton said the center has over 1,000 filters they can attach to 3D printed masks and has the capacity make about 30-80 masks a day.

A health care worker working on the front lines of the COVID-19 pandemic at St. Joseph's hospital gets fitted for a protective mask made by the Barrow Neurological Institute's Innovation Center. Courtesy of the Barrow Neurological Institute's Innovation Center

Kirk was among the first wave of health care workers at St. Joseph's to receive a mask and was fitted for it on April 3.

"I've been wearing it religiously since," he said.

So far, he has had no complaints and said breathing through the masks feels similar to breathing through an N95 mask with one exception: The fit is better.

With the N95 masks, Kirk said some doctors and nurses experience issues with fit. A silicone mold on the printed mask conforms to the face, so they don't slip as often as the N95 masks do.

Mike Lawton, Barrow Neurological Institute We're not interested in making any money off of this. ... All we're thinking about is getting masks to those who need them. Quote icon

For some of the nurses he works with, getting the new masks "feels like Christmas."

"It's snug against your nose, it's snug against your chin and it's snug against your cheeks," Kirk said. "I don't know anyone that hasn't had a good fit."

After they outfit all the nurses and doctors at St. Joseph's Hospital with masks, the center may look into expanding to make masks for other hospitals, Lawton said. The center has also released a free guide on how to make the masks and has shared their 3D printing design for free on GitHub.

"In theory, anyone who has a 3D printer can download the formula for making these and run their 3D printers and produce them in their own home," Lawton said. "We're not interested in making any money off of this ... all we're thinking about is getting masks to those who need them."

A view of the 3D mask design. Alex Li/The Republic

As many as the supply chain will allow

Making the masks is a labor-intensive process that involves casting a form-fitting silicone mold for each mask that ensures stray particles won't get into someone's mouth or nose, then fitting it to the 3D printed mask and attaching a P100 filter cartridge.

Lawton didn't have an exact estimate for how long it took to make one mask, but said 3D printing the plastic component of the mask takes the most amount of time.

"We have our engineers and our folks who run the lab there from sunrise to beyond sunset," he said. "They're putting in long days, probably 16 hour days ... and they just keep these things rolling off the assembly."

Hospital makes reusable masks in response to shortage Unlike N95 masks, these P100 masks are reusable and the design can be replicated by anyone with a 3D printer. Amanda Morris, Arizona Republic

The idea for the masks came from neurosurgical residents at the center, which has traditionally been a workshop space for medical trainees to innovate and design new medical tools.

"It started off as a concern about PPE, then morphed into this idea that we could create our own PPE and then we took off from there," Lawton said. "It's really a redeployment of a lab space that was intended for research and device development into something that is now a community service and really a critical part of this shortage of personal protective equipment."

Residents tested about 30 different prototypes before finalizing the design. The center started making these masks on March 27, and hasn't stopped since. So far, over 100 front line workers at St. Joseph's Hospital have received masks.

"Half of the battle in this crisis management is preparedness...we want to be prepared for the worst," Lawton said. "Our most valuable resource in this whole crisis is ... our doctors, nurses, all of our staff. So we're concerned about their safety and we don't want to find ourselves in some predicament in the future where we don't have PPE for them."

The masks made by the center are designed to only fit with P100 filter cartridges. Lawton said he is not experiencing any shortages of P100 filters, but he anticipates that, like the N95 mask, a high demand for the filters could cause shortages in the future.

Other supplies to make the mask — silicone and 3D printing plastic — are relatively cheap and shouldn't be hard to get.

"We're going to make as many of these masks as our supply chain will allow us to do," he said. "Once we run out, then we are also trying to come up with our own home-grown filtration cartridge."

Recreating the filtration cartridge itself is possible, Lawton said, but more work needs to be done to figure out how the center can produce them.

How big is the novel coronavirus? Republic reporting; illustration by Nicole Schaub

The filters themselves are essentially a mesh of fibers forming a screen that allows air to move through, but is thick enough to catch small particles. If the mesh screen is too thick, it becomes difficult to breathe, like breathing through a straw, Lawton said.

The novel coronavirus is thought to be 50-200 nanometers in diameter, according to a study from China that examined 99 cases of COVID-19 in patients. In comparison, a strand of hair is about 100,000 nanometers in diameter.

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"They're extremely small and so the paper has to be pretty dense," Lawton said. "If we can solve the filter problem, then we could take this to scale and get other hospitals and other people who are in need of them protected."

In the meantime, the masks the center is currently making have helped Kirk feel more comfortable about going to work every day. He said he counts himself lucky that his staff have a better level of protection with the new masks.

"I don't know that anybody else has copied us, but if they haven't, they should," Kirk said.

Amanda Morris covers all things bioscience, which includes health care, technology, new research and the environment. Send her tips, story ideas, or dog memes at amorris@gannett.com and follow her on Twitter @amandamomorris for the latest bioscience updates.

Independent coverage of bioscience in Arizona is supported by a grant from the Flinn Foundation.

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