N95 masks to protect healthcare workers from exposure to SARS-CoV-2 are still in urgent need, especially in the United States, as the number of new COVID-19 cases continues to rise. Hospitals in Texas and Florida are overwhelmed with the volume of new patients recently, and N95 respirators are in short supply. Healthcare workers have been forced to wear their masks for longer than intended, and some started disinfecting them to be reused. And while disinfection works, the process requires specialized equipment and takes time.
To help with this dilemma, researchers and engineers at Brigham and Women’s Hospital and MIT have designed a new kind of reusable mask made of transparent and durable silicone rubber. It’s called the iMASC – which stands for Injection Molded Autoclavable, Scalable, Conformable. So far, testing has proven it is as effective as N95 masks at stopping viral particles, and it’s comfortable to wear. Furthermore, it’s easy to sterilize and can be manufactured quickly.
James Byrne, a radiation oncologist at Brigham and Women’s Hospital and researcher at MIT’s Koch Institute for Integrative Cancer Research, who is also part of the team, said:
When the virus started popping up in the U.S., we talked about the need for PPE, and identified really early on that there was going to be a large deficit within the United States as well as the world. We really put our heads together to try to come up with something that was sustainable, and that’s how we really came up with this reusable, scalable, conformable, flexible mask.
The iMASC can be manufactured using injection molding – a widely used technique in factories around the world. The mask also includes a minimal amount of N95 material for the filters. There are slots for two small disposable disks of N95 material in the front.
Giovanni Traverso, a gastroenterologist at Brigham and Women’s Hospital and an MIT assistant professor of mechanical engineering, who is part of the multidisciplinary team developing the new mask, said:
Having something that was scalable, meaning that we could relatively quickly make many to support a large population was critical. Injection molding of silicone is something that is recognized in the industry.
One of the key things we recognized early on was that in order to help meet the demand, we needed to really restrict ourselves to methods that could scale. We also wanted to maximize the reusability of the system, and we wanted systems that could be sterilized in many different ways.
The rubber part of the masks can be sterilized by putting them in an oven, using a steam sterilizer, and soaking them in rubbing alcohol or bleach. The N95 disc filters are to be removed and discarded after each use. While the masks still produce some waste, it’s much less than having to throw away a whole mask every time.
Adam Wentworth, a research affiliate at the Koch Institute and a research engineer at Brigham and Women’s Hospital, said:
With this design, the filters can be popped in and then thrown away after use, and you’re throwing away a lot less material than an N95 mask.
The team even recruited a group of 24 healthcare workers to test the comfort and fit of the iMASC following the procedure required by the Occupational Safety and Health Administration for N95 masks. All the participants passed the fit-test and gave high ratings for comfort and breathability.
Now, the testing continues while the group works on a second mask design with the hopes of making it even more durable and comfortable. They plan to have their final product approved by the National Institute for Occupational Safety and Health and the FDA so they can bring it to the market as soon as possible.
Byrne said:
We know that COVID is really not going away until a vaccine is prevalent. I think there’s always going to be a need for masks, whether it be in the health care setting or in the general public.
A switchover to reusable masks could save hospitals lots of money. One iMASC is expected to cost $15, but it can be used up to 100 times. One N95 mask costs between $2.80 and $6.95, but it can only be used once.
