With the coronavirus pandemic infecting more than 690,000 people globally and claiming the lives of over 33,000, governments and medical authorities are scrambling to find new ways to contain the spread of the virus.
Surgical masks have emerged as a necessity for health care workers, infected patients, and those highly susceptible to infection such as people with chronic respiratory illnesses. However, experts note that they do have their limitations.
Biomedical engineer and professor of chemical and material engineering at the University of Alberta in Canada, Hyo-Jick Choi said during an interview with Canadian television network CTV: “What most people don’t realize is that current masks are limited when it comes to preventing transmission.”
“The problem with surgical masks is that they only provide protection against large coronavirus-laden droplets, whereas much smaller virus-carrying droplets called aerosols can penetrate through masks.”
“Once contaminated, viruses can live on the surface of the filter for hours and up to a week and are at risk of being spread to other surfaces when the masks are handled,” Choi added.
“People have a tendency to touch their face every four minutes and contaminated hands can easily spread the disease from person-to-person and contaminate other surfaces.”
He added that “we have to understand that with surgical masks we have to replace them with a new one every few hours,” noting that the masks are essentially useless if re-used.
Therefore, Choi and his team are looking into a solution to increase the efficacy of surgical masks.
In 2017, Choi and his team published a research paper detailing the results of their experiments with coating surgical masks and respirators with sodium chloride salt (NaCl). They tested the coating on three strains of the influenza virus and found it was able to neutralize the virus.
The research paper states: “The salt coating on the fiber surface dissolves upon exposure to virus aerosols and recrystallizes during drying, destroying the pathogens.”
“When tested with tightly sealed sides, salt-coated filters showed remarkably higher filtration efficiency than conventional mask filtration layer, and 100 percent survival rate was observed in mice infected with virus penetrated through salt-coated filters.”
When Choi’s team tested the coating on three different strains of influenza virus, all of them were deactivated within 30 minutes of being exposed to the sodium chloride.
Choi’s team said in their paper that their results “can be applied in obtaining a broad-spectrum, airborne pathogen prevention device in preparation for epidemic and pandemic of respiratory diseases.”
Their technique of using NaCl salt was found to be a stable one as the salt coating was not compromised by high temperature and humidity, which suggested safe use and long-term storage as well as reuse.
Choi has a provisional patent on the salt-coating technology, and his team hopes to make the devices commercially available within the next 18 months.
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