New Reusable, Silicone Rubber Face Mask With Replaceable N95 Filters By MIT

Reusable Silicone Rubber Facemask By MIT & BWH Research Team

A new face mask capable of stopping viral particles as effectively as N95 masks have been designed by the researchers at MIT and Brigham and Women’s Hospital. The new masks were designed to be easily sterilized and used many times, unlike N95 masks.

The new mask can be manufactured using a widely used method in factories around the world, injection molding, as the mask is made of durable silicone rubber. The masks require much less N95 material than a traditional N95 mask and it includes an N95 filter. In the British Medical Journal Open, the senior author of a paper, Traverso describes the new masks.

The team is now working to seek approval from the FDA and the National Institute for Occupational Safety and Health (NIOSH) and establish a company to support scaled-up production and is also working on a second version of the mask, based on feedback from health care workers.

Polypropylene fibers that are specially designed to filter out tiny viral particles are used to make the N95 masks that health care workers wear to protect against exposure to SARS-CoV-2 and other viruses. Shortages of these masks have forced doctors and nurses to wear them for longer than they are meant to be worn, and if this was not the case, a health care worker would switch to a new mask each time they see a different patient.

Many hospitals in recent months have started sterilizing N95 masks with hydrogen peroxide vapor, which can be used up to 20 times on a single mask. But specialized equipment that is not available everywhere is required for this process and yet one mask can be worn for only a single day even with this process.

The MIT/BWH research team began to design a mask that could be reused many times and safely sterilized. Due to its durability, they decided to use the material that goes into silicone baking sheets, silicone rubber. Using injection molding, liquid silicone rubber can be easily molded into any shape.

The masks are based on the type normally used at Brigham and Women’s Hospital, the shape of the 3M 1860 style of N95 masks. The masks are made of silicone rubber and include space for one or two N95 filters. While the rest of the mask can be sterilized and reused, those filters are designed to be replaced after every use.

This means the users will be throwing away a lot less material than an N95 mask, as the filters can be popped in and then thrown away after use with this design.

Several different sterilization methods on the silicone masks, including soaking them in bleach and in isopropyl alcohol, putting them in an oven, and running them through an autoclave (steam sterilizer) were tested by the researchers. The silicone material was found to be undamaged after sterilization.

From the emergency department and an oncology clinic at Brigham and Women’s Hospital, the researchers recruited about 20 health care to test the comfort and fit of the masks. The standard-fit test that is required by the Occupational Safety and Health Administration (OSHA) for N95 masks was performed by each of the subjects. A series of movements is performed by the subject after putting the mask on to see if the mask stays in place, in this test. The mask is considered not to be fitted properly if the subject can taste or smell the nebulized sugar solution which is sprayed in the room.

All 20 subjects reported that they were able to successfully insert and remove the N95 filter and passed the fit-test. When the subjects were asked about their preference between a standard surgical mask, a typical N95 mask, and the new mask, the gave the new mask high ratings for fit and breathability and most either said they had no preference or preferred the new silicone mask.

The research was funded, in part, by the MIT Department of Mechanical Engineering, the Prostate Cancer Foundation, the Hans and Mavis Lopater Psychosocial Foundation, Philips Biosensing, Gilead Sciences, E-Ink Corporation, the National Institutes of Health, and Brigham and Women’s Hospital.

Source
Reusable Silicone Rubber Facemask By MIT & BWH Research Team