The N95 face mask may soon be passé as researchers develop a sterilizable alternative.Silicon Rubber face mask, A new reusable innovation as effective as N95

With N95 masks in short supply, a team of bioengineers and clinical experts from Brigham and Women’s Hospital and the Massachusetts Institute of Technology (MIT) has been developing a new, sustainable solution for health care workers to provide protection during the pandemic. Made from sterilizable materials and known as the Injection Molded Autoclavable, Scalable, Conformable (iMASC) system, the team’s N95 face mask alternative is still in its prototyping stage. But early results from modeling and a feasibility study for fit testing suggest that the iMASC system could fit faces of different sizes and shapes and be sterilized for reuse. Preliminary findings are published in the British Medical Journal Open. 

A Silicone Mask For Comfort

According to researchers from MIT, given the current COVID-19 crisis which has lead to an acute shortage in personal protective equipment, they wanted to do something to help. This led to the development of a mask system that could be readily sterilized in many different ways and reused. 

Researchers selected DOW Corning QP1-250 liquid silicone rubber (LSR) for their mask material. Silicone rubber can withstand heat of up to 572 degrees Fahrenheit and is used in a wide variety of products, including silicone baking sheets, undergarments, medical implants and medical devices such as respiratory masks used to deliver anesthesia. The team created the masks using injection molding — a common manufacturing technique in which a liquid material is fed into a mold cavity to give it shape. Elastic straps secure the mask in place and two replaceable filters keep out solid particles. They selected materials that can be easily sterilized and are also comfortable to wear. 

One Size Fits All

Using 3D modeling, researchers evaluated how the face mask might fit on different wearers and how much force would be required to keep the mask secure on a range of face shapes and sizes. In addition,silicon rubber the team recruited health care workers from the Brigham in a small fit testing study. Of the 20 participants who performed fit testing, 100 per cent completed the process successfully. When asked about their preferences, 60 per cent participants said that they would be willing to wear the iMASC system instead of a surgical mask, 20 per cent had no preference. When asked if they would prefer this to N95, 25 per cent said they would prefer the iMASC system while 60 per cent indicated no preference.

Sterilizing The Masks

Researchers tested various sterilization techniques on the masks, including autoclaving, silicon rubber soaking in a bleach solution and soaking in isopropanol. They saw that while 10 autoclave cycles, the masks became slightly stiffer, there was no large differences in the sterilized masks compared to the masks before sterilization. According to them, they wanted to create a mask that could be easily sterilized and reused for several reasons. Not only is this important because of disruptions to the supply chain, but also disposable masks, gloves and other PPE can cause a tremendous amount of litter.

The Limitations

Researchers, however, acknowledge the fact that fit testing and surveys were conducted among only a small number of people at a single institution. Modifications to the filter system and elastic straps would likely improve the fit and robustness of the mask. And large-scale production will require greater quality control of filter components. These are some of the limitations that they point out. A multi-institutional trial of the new system is now complete.

Originally posted at : Thehealthsite