As governments around the world struggle to build up a supply of N95 masks for healthcare workers—navigating price gouging, counterfeit respirators, scammers, and fierce competition from other governments—some hospitals are still taking care of COVID-19 patients without adequate supplies, and reusing masks that were designed to be disposable.
A new design could make N95 masks safely reusable. In a new study, engineers from King Abdullah University of Science and Technology in Saudi Arabia created a new membrane that can be added to the front of an N95 mask and then replaced while the rest of the mask is used repeatedly. (The engineers don’t specify how the membrane is attached.) The filter, which can be made either from polymer or paper, is covered with nano-size holes that also make the mask more effective.
While an N95 mask can filter out droplets of saliva when someone coughs or talks, it can’t fully filter out the virus if the virus is “aerosolized,” or hanging in the air by itself in much smaller particles. But the holes in the new membrane are so small that these tiny particles can’t pass through. The material could also be modified with a hydrophobic coating that makes droplets slide off easily, so the tiny holes don’t become clogged.
Instead of using an N95 mask once, or attempting to sterilize it when it wasn’t designed to be sterilized, a doctor or nurse could replace the new filter on the front of the mask. It’s also more cost-effective, the engineers say. A one-time-use N95 mask might cost $5. “Keeping the frame and replacing the breathing portion using membranes will allow the frame to be used at least 10 times,” says Muhammad Mustafa Hussain, a professor of electrical engineering at King Abdullah University of Science and Technology. The new membrane might cost 50¢, so a mask could be used 10 times for the cost of two new N95s.
Mask manufacturers like Honeywell and 3M have ramped up the production of N95 masks in response to the pandemic, and in the U.S., the government says that it is in the process of shipping or coordinating the delivery of 86 million masks, with contracts to buy another 600 million masks. But the government has estimated that it needs 3.5 billion masks in a pandemic—and that’s in the U.S. alone. The rest of the world also needs a massive supply. “We do not see how supply chains can be managed for such a high volume,” says Hussain. “We are especially concerned that there can be another surge in fall, and based on our behavior a second wave may hit in summer too.” Now, he says, the team wants to validate the efficacy of the filters and work with manufacturers to quickly bring the new product to market.