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Mask with anti-viral layer can inactivate COVID-19 virus



Mask with chemical modulation layer

The schematic diagram shows how the chemically modulated layer “sterilizes” the breath droplets of the mask wearer.Credit: Northwestern University

The anti-virus layer attacks respiratory droplets, reducing the infectivity of the mask wearer.

In a pandemic, people wear masks to respect and protect others, not just to protect themselves, Northwest University Researchers.

With this in mind, the researchers developed a new mask concept designed to reduce the wearer’s infectivity. The central idea is supported by the National Science Foundation through RAPID grants, and its purpose is to modify the mask fabric with antiviral chemicals to purify exhaled and escaped respiratory droplets.

By simulating inhalation, exhalation, coughing and sneezing in the laboratory, the researchers found that the non-woven fabric used in most masks proved this concept well. For example, a lint-free wipe with a fiber density of only 19% can disinfect up to 82% of escaped breath droplets. The fabric does not make breathing more difficult, and the chemicals on the mask will not fall off during the simulated inhalation experiment.

The research will be published in the journal today (October 29, 2020) Thing.

The importance of protecting others

Huang Jiaxing of Northwest Airlines, who led the study, said: “Masks may be the most important part of personal protective equipment (PPE) needed to fight the pandemic.” “We quickly realized that masks can not only protect people wearing masks. , And more importantly, it prevents other people from being exposed to water droplets (and bacteria) released by the wearer.

Huang added: “The wearing of masks seems a bit confusing, because some people think they don’t need physical protection.” “Maybe we should call them public health equipment (PHE) instead of PPE.”

Optical microscope of droplets

The optical microscope image in the reflection mode (left) shows the dry traces of all the droplets collected on the polyaniline film, but in the transmission mode, only the acid-modified droplets (right) are visible, as they will be The color of the aniline film changed from blue to green. Scale bar: 200 microns.Credit: Northwestern University

Huang is a professor of materials science and engineering at the Northwest McCormick School of Engineering. Haiyue Huang’s graduate student and Dr. Huang’s laboratory member Dr. Hong are both the first author of the paper.

The 2020 Lion Scholarship recipient Huang Haiyue said: “In places where infectious respiratory diseases have broken out, controlling the source is the most effective way to prevent the spread of the virus.” “After they leave the respiratory tract, the respiratory droplets will spread more and become more difficult to control.”

Goals and results

Although masks can stop or redirect exhaled respiratory droplets, many droplets (and the viruses embedded in them) can still escape. From there, the virus-laden droplets can directly infect another person or fall on the surface to infect another person indirectly. Huang’s team aims to chemically modify the escaped droplets so that the virus inactivates more quickly.

For this reason, Huang tried to design a mask fabric: (1) it will not make breathing more difficult, (2) it can be loaded with molecular antiviral agents, such as acid And metal ions that are easily dissolved in the escaped droplets; and (3) It does not contain volatile chemical substances or materials that are easily inhaled by the wearer.

After many experiments, Huang and his team chose two famous antiviral chemicals: phosphoric acid and copper salt. These non-volatile chemicals are attractive because they do not vaporize and are potentially inhaled. Both will create a local chemical environment that is not conducive to the virus.

Huang said: “The structure of the virus is actually very fragile and fragile.” “If any part of the virus fails, then it will lose the ability to infect.”

Huang’s team grew a layer of conductive polymer polyaniline on the surface of the mask fabric fibers. The material adheres firmly to the fibers and acts as a reservoir for acid and copper salts. The researchers found that even loose fabrics with a low fiber bulk density of about 11%, such as gauze, still changed the volume of exhaled breath droplets by 28%. For tighter fabrics, such as lint-free wipes (the type of fabric commonly used for cleaning in the laboratory), 82% of the breath drops need to be modified.

Huang hopes that his current work will provide other researchers, especially researchers in other parts of the world, with their own version of this chemical regulation strategy, and use virus samples and even patients to test them to provide scientific evidence.

Huang said: “Our research has become a kind of open knowledge, and we hope to see more people join this work to develop tools to strengthen public health responses.” “This work was almost completely completed during the closure of the laboratory. It is done in the laboratory. We hope to show researchers that researchers in non-biological aspects of science and engineering, as well as those who do not have many resources or contacts, can also contribute their energy and talents.”

Reference: October 29, 2020, Thing.

This work is mainly supported by the National Science Foundation (RAPID DMR-2026944).




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