American scientists have described how a normal face mask injected with antiviral chemicals can “turn off” the coronavirus.
Their concept uses phosphoric acid and copper salt to kill the virus, which coats a layer of polyaniline – a polymer that could coat regular face mask fabric.
The antiviral chemical layer attacks the respiratory droplets that contain the virus, making mask wearers less infectious.
Widely available face masks feature a layer of bonded non-woven fabric – usually polypropylene – which gives them high strength.
By simulating inhaling, exhaling, coughing and sneezing in the lab, researchers found that certain nonwoven fabrics disinfect up to 82% of the respiratory droplets that escape.
The diagram shows how a chemical modulation layer “disinfects” the respiratory droplets of the face mask wearer.
The chemical layer could offer an improvement over normal masks, which does not prevent all virus-laden droplets from escaping from the wearer’s mouth and nose.
“Masks are perhaps the most important piece of personal protective equipment needed to fight a pandemic,” said study leader Jiaxing Huang of Northwestern University in Illinois.
“We quickly realized that a mask not only protected the person wearing it, but, more importantly, it protected others from being exposed to droplets and germs released by the wearer.
Although masks can block or redirect exhaled respiratory droplets, many droplets and their embedded viruses still escape.
From there, virus-laden droplets can infect another person directly or land on surfaces to indirectly infect other people.
Huang’s team aimed to chemically modify the exhaust droplets to make viruses deactivate faster.
They wanted to identify molecular antiviral agents such as acidic and metal ions that can easily dissolve in the escaping droplets.
After performing several experiments, they selected two well-known antiviral chemicals – phosphoric acid and copper salt.
Although masks can block or redirect exhaled respiratory droplets, many droplets (and their embedded viruses) still escape. From there, virus-laden droplets can infect another person directly or land on surfaces to indirectly infect other people. Huang’s team aimed to chemically modify exhaust droplets to make viruses deactivate faster.
Neither of these could potentially be inhaled by the face mask wearer and both create a local chemical environment that damages the SARS-CoV-2 viral envelope – its outermost layer.
“Viral structures are actually very delicate and brittle [and] if any part of the virus is not working properly, it loses the ability to infect, ”Huang said.
Huang’s team grew a layer of a conductive polyaniline polymer on the fiber surface of the mask fabric.
The material adheres strongly to the fibers, acting as reservoirs for acid and copper salts.
The coronavirus is a type of enveloped virus, which means it has an outer lipid membrane that could be damaged by chemicals. Naked viruses do not have the viral envelope
Researchers found that even loose fabrics with low fiber packaging densities of around 11%, like medical gauze, changed 28% of exhaled respiratory droplets in volume.
For tighter fabrics, such as lint-free wipes, the type of fabric typically used in the lab for cleaning, 82 percent of the respiratory droplets were changed.
Polyaniline – the polymer they used to coat fabrics – is a great color indicator for the acid itself as it turns from dark blue to green.
He was therefore able to measure and quantify the degree of chemical modification of the escaped droplets.
The light microscopy image (left) in reflectance mode shows the drying marks of all the droplets collected on a polyaniline film, but only the acid-modified ones (right) are visible below as they change color of the underlying polyaniline film from blue to green. Scale bar: 200 microns
People wear face masks to protect others from the viral droplets they might emit, rather than to protect themselves.
US Democratic presidential candidate Joe Biden recently had to remind President Donald Trump of this fact, saying that face masks should be “seen as a patriotic duty to protect those around you.”
“There seems to be some confusion about wearing the mask because some people don’t think they need personal protection,” Huang said.
“Maybe we should call it public health equipment (PHE) instead of PPE.
The concept of a mask is detailed later in the Matter review.
UK FACE MASK POLICY
Face masks should be worn on public transportation and in many indoor spaces, including stores, malls, indoor transportation hubs, museums, galleries, cinemas, and public libraries.
It is currently legal for passengers to wear face masks in taxis and private rental vehicles, in hospitality areas, such as restaurants and bars, except when eating and drinking. Staff in retail and hospitality establishments are also legally required to wear masks.
If necessary, police and Transport for London (TfL) agents have enforcement powers, including fines of £ 200 (halved to £ 100 if paid within 14 days).
This comes after the World Health Organization and numerous studies suggest that they are beneficial.
As announced, the government will introduce changes to mean that for repeat offenders these fines would double for each offense up to a maximum value of £ 6,400.
The Prime Minister also announced tougher enforcement measures, with businesses facing fines or closures for not following coronavirus rules, meaning there will be consequences for pubs that try to serve you. at the bar.
Chairman of the National Council of Chiefs of Police Martin Hewitt said: “Individuals, businesses and households all have a responsibility to ensure that the virus is removed and that the police will play their part in helping the public to navigate the measures in place for our safety.
“Our approach of engaging with people and explaining the regulations in place will remain. The vast majority of situations are resolved by following these two steps, with little encouragement or coercive action to be taken, ”he said.
“The police will continue to work with their communities and will only issue fines as a last resort.
“The leaders will step up patrols in high-risk areas and work proactively with businesses, licensing authorities and local authorities to ensure the rules are followed.
“If members of the public are concerned that the law is being broken or that they are engaging in anti-social behavior, they can report it to the police, who will investigate the most appropriate response and target the most problematic behavior. “