The Injection Molded Autoclavable, Scalable, Comfortable (iMASC) system developed by bioengineers and clinicians at Brigham and Women’s Hospital.
At Brigham and Women’s Hospital, the biomedical research lab of Giovanni Traverso, MB, BChir, PhD recently developed a new reusable, scalable alternative to N95 masks, which have been in short supply within healthcare settings during the COVID-19 pandemic.
Known as the Injection Molded Autoclavable, Scalable, Comfortable (iMASC) system, the N95-comparable face mask is still in its prototyping stage. However, a recent single-arm feasibility study in BMJ Open showed that the iMASC system could fit faces of different sizes and shapes and be easily sterilized for reuse.
To build the iMASC system, Dr. Traverso and his colleagues, including co-lead authors James Byrne, MD, PhD, and Adam Wentworth, MS, worked closely with bioengineers and clinical experts at the Brigham and the Massachusetts Institute of Technology (MIT).
“When the pandemic began, everyone in our group had this urge to help,” says Dr. Traverso, a gastroenterologist in the Brigham’s Division of Gastroenterology and a biomedical engineer at MIT. “We recognized that we were privileged to have a talented team of individuals from many backgrounds as well as the access, facilities and industry partnerships to bring innovative solutions to bear on this public health challenge.”
Recent Innovations in the Fight Against COVID-19
Since the beginning of the COVID-19 pandemic, the biomedical research lab of Giovanni Traverso, MB, BChir, PhD has been developing innovative and sustainable solutions to protect health care workers on the front lines. The interdisciplinary team of engineers, scientists and physicians in the Traverso Lab recently invented a system for ventilator splitting, which published in the June issue of Science Translational Medicine. The lab also collaborated with industry partners to build a dog-like robot that facilitates contactless evaluation of COVID-positive patients.
Feasibility Study Evaluated the Innovative Face Mask
The team’s feasibility study used an Occupational Safety and Health Administration (OSHA)-approved testing method to evaluate the iMASC’s fit on physicians, nurses and technicians at the Brigham. The average age of the 20 male and female participants who completed the study was 41 years (range of 21 to 65 years) with an average body mass index of 26.5 kg/m2. Healthcare workers with facial hair were excluded from enrollment.
All 20 study participants passed their fit test and were also able to successfully replace the filter into the mask, resulting in a 100 percent success rate for both fit testing and filter exchange. The study also tested the iMASC’s breathability. Participants scored the breathability of the iMASC system as “excellent” (9 participants), “good” (10 participants) or “fair” (1 participant).
The iMASC was Built for Comfort
As some health care workers have complained of the traditional N95 mask’s comfort, Dr. Traverso’s team designed the iMASC to be comfortable to wear for long periods of time. To this end, they used 3D modeling to evaluate how the iMASC 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.
The feasibility study demonstrated that the iMASC could be worn comfortably for 15 minutes with the hope that it could worn for the duration of a typical hospital shift. When asked about their preferences, participants responded that: 60 percent would be willing to wear the iMASC system instead of a surgical mask while 20 percent had no preference, and 25 percent would prefer the iMASC system instead of an N95 mask while 60 percent indicated no preference.
Maximizing Scalability at the Outset
“The team was thinking about scalability from the beginning,” says Dr. Byrne, a resident in the Brigham’s Department of Radiation Oncology and a postdoctoral fellow in the Traverso lab. “In this regard, we selected a manufacturing process that’s proven to be scalable as well as materials that were recognized to be sterilizable and comfortable.”
To ensure maximum scalability, the iMASC was created using injection molding—a common manufacturing technique in which a liquid material is fed into a mold cavity to give it shape. The mask is made from DOW Corning QP1-250 liquid silicone rubber (LSR). Silicone rubber can withstand heat of up to 572 degrees Fahrenheit and is used in a wide variety of products, including medical devices such as respiratory masks used to deliver anesthesia. Elastic straps secure the mask in place and two replaceable filters keep out solid particles.
The iMASC can be Sterilized Using Several Methods
While filters must be replaced after each use of an N95 mask, the iMASC can be more easily sterilized than regular N95 masks, therefore reducing waste. “We created a mask that can be easily sterilized and reused,” says Wentworth, a research engineer in the Traverso lab. “Not only is this important because of disruptions to the supply chain, but also disposable masks, gloves and other personal protective equipment (PPE) can cause a tremendous amount of litter.”
The feasibility study showed that the iMASC could be sterilized using a variety of methods. This includes autoclaving, a commonly used sterilization method that uses high-pressure steam to eliminate microorganisms. Given that not every health care setting has access to sophisticated sterilization equipment, such as an oven for autoclaving, the iMASC can be also be sterilized by soaking in a bleach solution, or isopropanol.
Continually Improving the Design of the iMASC System
Based on feedback from health care workers, the Traverso lab has further refined the iMASC. For example, the team modified the filter system and improved the fit by modifying the elastic straps. The mask’s dual filters were also moved further apart to increase visibility of the mouth.
“This iMASC 2.0 allows patients to see more of their provider’s lips and facial expressions,” says Dr. Traverso. “This may help improve clinical interactions between patients and providers. The feature also gives patients with a hearing impairment the ability to read lips.”
Taking the iMASC Prototype from Bench to Bedside
The Traverso lab recently finished a multi-institutional trial of the iMASC 2.0 system. The study, which hasn’t yet published, was led by Wentworth and Dr. Byrne and involved more than 40 health care workers from the Brigham and Massachusetts General Hospital (MGH). The study showed encouraging results, including a successful fit on all participants.
The team is currently working with the FDA to secure an emergency authorization use of the most up-to-date version of the iMASC. They hope to be able to offer the face mask to health care workers and the public by the end of the year.
“It’s the dream of every biomedical engineer and physician-scientist to see their invention tested in health care workers as we did in our study,” says Dr. Byrne. “We hope to offer the iMASC to the community of health care workers and the general public as soon as possible.”