MIT researchers develop reusable silicone N95-type mask

Engineers at MIT are designing a reusable silicone rubber face mask modelled on the N95 respirator in an effort to reduce health waste and plug a shortage for masks amid the pandemic.

The new masks, which come fitted with two disposable N95 filters that trap virus particles, were developed by researchers at MIT and Brigham and Women’s Hospital in Boston.

A big advantage of the iMASC (Injection Molded Autoclavable, Scalable, Conformable) mask is how quickly and efficiently it can be sterilised and reused and the limited quantity of N95 material it uses in the system.

“One of the key things we recognised early on was that in order to help meet the demand, we needed to really restrict ourselves to methods that could scale,” said Giovanni Traverso, an MIT assistant professor of mechanical engineering and a gastroenterologist at Brigham and Women’s Hospital.

“We also wanted to maximise the reusability of the system, and we wanted systems that could be sterilised in many different ways,” he added.

Limited availability of personal protective equipment (PPE) have been a paint point for healthcare workers at the frontline of the coronavirus pandemic across hospitals in the US. Many healthcare professionals were forced to use disposable masks for several days at the height of the pandemic, making them particularly vulnerable to contracting Covid-19 infection. Other workers resorted to sterilising disposable masks and reusing them to reduce the risk of infection.

The MIT team is now working on a second version of the iMASC, based on inputs from health workers. The research team also plans to scale up production of the silicone-based mask and will work to secure approval from the Food and Drug Administration.

The N95 masks have proven more effective against airborne viral particles - the main mode of transmission of Covid-19 - as they are manufactured from polypropylene fibres, which filter out these tiny particles.

A normal N95 mask is meant to be worn for a single day, though stricter procedures mandate changing it after a doctor sees a different patient. Some hospitals use hydrogen peroxide vapour to sterilise a used N95 mask, which allows it to be used up to 20 times. However, not many clinics are equipped with such sterilisation equipment.

Around 20 healthcare workers from the Brigham and Women’s Hospital undertook a test to gauge the mask's effectiveness. The workers were sprayed with a nebuliser sugar solution while wearing the mask.

If the subjects were able to smell the solution, those masks would fail the fit test. However, the healthcare reporters said the new mask trapped the particles effectively and fit better than a standard surgical mask.

The US is among the countries hit hardest by the coronavirus pandemic, accounting for a quarter of the 15.2 million infections world-wide. The world's largest economy also accounts for the highest number of fatalities from the virus, with 143,193 succumbing to Covid-19 so far, according to the Johns Hopkins University tracker.