With the practice of wearing masks and regular disinfection becoming the norm in the middle of the global coronavirus pandemic, developing and improving masks have become a point of interest in the scientific community. Now, researchers have fabricated a chemically-altered face mask that can "deactivate" pathogens such as the novel coronavirus.
A research team from Northwestern University in Evanston, Illinois, has proposed a method that would allow a face mask to chemically modulate exhaled droplets and make them "less infectious." The details of their work are published in the journal Matter.
Modifying Fabrics into Pathogen Filters
A face mask that sanitizes respiratory droplets would greatly reduce the risks of transmitting diseases that rely on air or droplets. Researchers simulated respiratory actions - inhaling, exhaling, coughing, and sneezing in a laboratory setup to demonstrate their proof of concept. It showed non-woven fabrics incorporated into commercially available face masks work well. For example, a lint-free wipe of 19 percent fiber density can sanitize up to 82 percent of expelled respiratory droplets by volume.
Researchers also reported that the non-woven fabric in the experiment did not hinder respiration, and the chemicals in the altered mask were not expelled during the simulated respirations.
Testing The Best Antiviral Add-On
Researchers worked to design a mask material that meets several criteria. First, it should not impede breathing, making it difficult. Next is that fabric they are looking for must have sufficient capability for carrying molecular antiviral agents - metal ions and acids - that can easily attach themselves to the expelled droplets. Lastly, researchers are looking for a fabric that does not have volatile chemicals or parts inhaled by the user with repeated use.
Experimental trials narrowed down the potential antiviral agents into two: copper salts and phosphoric acid. Researchers argue that both materials do not vaporize, which means a reduced risk of these materials being inhaled. Also, both materials can create a local environment that inhibits viruses.
"Virus structures are actually very delicate and 'brittle,'" Huang explained, adding that if a part of the pathogen malfunctions," it becomes mostly unable to infect others.
Researchers coated the fiber with a layer of conducting polymer polyaniline to fabricate their chemically-altered mask, chosen for being easy to grow and its ability to bind with both acids and ions.
Inhibiting Transmission of Infectious Materials
"Masks are perhaps the most important component of the personal protective equipment (PPE) needed to fight a pandemic," explained Jiaxing Huang, leader of the research team from Northwestern University. This led to the realization that the mask does not just protect its wearer but also the wearer's people.
Huang also addressed the misconception among some people who do not believe in the need for masks in the middle of the pandemic in an article from Northwestern, suggesting that PPEs be called "public health equipment" (PHE) instead.
"Where there is an outbreak of infectious respiratory disease, controlling the source is most effective in preventing viral spread," said Haiyue Huang, an author in the study and a 2020 Ryan Fellowship Awardee. He added that once these are expelled into the environment, it makes it more difficult to control the spread of these particles and the microbes within them.
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