Researchers develop sterilizable, alternative N95 mask

Date:
July 8, 2020
Source:
Brigham and Women's Hospital
Summary:
Early results from modeling and a feasibility study for fit testing
suggest that the iMASC system, an N95 mask alternative, could fit
faces of different sizes and shapes and be sterilized for reuse.



FULL STORY ==========================================================================
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 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.

"Like many of our colleagues, when we heard about shortages in personal protective equipment, we wanted to help. We thought that an approach that
could be helpful would be to develop a mask system that could be readily sterilized in many different ways and reused," said corresponding author Giovanni Traverso, MB, BChir, PhD, a gastroenterologist and biomedical
engineer in the Division of Gastroenterology at the Brigham and Department
of Mechanical Engineering at MIT.

Traverso and his colleagues, including co-lead authors James Byrne,
MD, PhD, and Adam Wentworth, MS, worked closely with the Massachusetts
General Brigham COVID Center for Innovation on their project. The
authors 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.

"From the beginning, we were thinking about scalability. We selected
materials recognized to be sterilizable and comfortable and a
manufacturing process designed to be scaled," said Byrne, a resident in
the Department of Radiation Oncology at the Brigham and a postdoctoral
fellow in the Traverso lab.

The team tested various sterilization techniques on the masks,
including autoclaving, soaking in a bleach solution and soaking in
isopropanol. While 10 autoclave cycles made the masks slightly stiffer,
there were no large differences in the sterilized masks compared to the
masks before sterilization.

"We 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," said Wentworth, a research
engineer in the Traverso lab.

Using 3D modeling, the team evaluated how the 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, the team recruited
health care workers from the Brigham in a small fit testing study. Of
the 20 participants who performed fit testing, 100 percent completed the process successfully. 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;
* 25 percent would prefer the iMASC system instead of an N95 mask
while 60
percent indicated no preference.

The authors acknowledge that their proof-of-concept study has several limitations. 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.

Based on their initial study, the team has further refined the iMASC,
and the authors have recently completed a multi-institutional trial of
the new system.

They continue to work with various partners from across Mass General
Brigham to test the system and are considering strategies to support
scaling up and deploying the iMASC.

This work was supported in part by the Prostate Cancer Foundation. Byrne
was supported by the Prostate Cancer Foundation Young Investigator
Award. Traverso was supported in part by the Department of Mechanical Engineering, MIT and Brigham and Women's Hospital. Co-authors were
supported by NIHK23DA044874, and investigator-initiated research grants
from e-ink corporation, Gilead Sciences, Philips Biosensing and the Hans
and Mavis Lopater Psychosocial Foundation.

Support for the materials and supplies was from discretionary funds
to Traverso from Brigham and Women's Hospital and the Department of
Mechanical Engineer, MIT.


========================================================================== Story Source: Materials provided by Brigham_and_Women's_Hospital. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. James D Byrne, Adam J Wentworth, Peter R Chai, Hen-Wei Huang, Sahab
Babaee, Canchen Li, Sarah L Becker, Caitlynn Tov, Seokkee Min,
Giovanni Traverso. Injection Molded Autoclavable, Scalable,
Conformable (iMASC) system for aerosol-based protection: a
prospective single-arm feasibility study. BMJ Open, 2020; 10 (7):
e039120 DOI: 10.1136/bmjopen-2020-039120 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200708105852.htm

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