A face mask that comes with a built-in heated copper mesh that can inactivate viruses such as Covid-19 is being developed by MIT researchers.
As the person wearing the mask breathes in and out, air flows repeatedly across the mesh, and any viral particles contained within are slowed and inactivated by the mesh and high temperatures.
Such a mask could be useful for healthcare professionals, the researchers say, as well as members of the public in situations where social distancing would be difficult to achieve, such as a crowded bus.
“This is a completely new mask concept in that it doesn’t primarily block the virus. It actually lets the virus go through the mask, but slows and inactivates it,” said MIT professor Michael Strano.
The researchers have begun building prototypes and hope to begin testing them soon.
The idea came after the researchers began digging through existing scientific reports on different types of masks, and found none that are designed primarily to kill viruses by heating.
“The masks that we wear now are designed to capture some of the virus. They do offer protection, but there’s no one really thinking about inactivating the virus and sterilising the air. That surprised me,” Strano said.
The team set out to design a mask that would kill viruses using heat. They decided to use copper mesh as the heating and capture element, and performed some mathematical modelling to determine the optimal temperature range they would need to achieve to kill coronaviruses flowing inward or outward from natural breathing.
“The vast majority of masks today function by filtration, filtering particles by size or electric charge,” said MIT graduate student Samuel Faucher. “This mask relies on a different mechanism and works predominantly by thermal inactivation.”
The researchers calculated how rapidly coronaviruses degrade at different temperatures and trapping conditions, and found that a temperature of about 90 degrees Celsius could achieve between a thousand-fold and million-fold reduction in viral particles, depending on the final mask size.
They also showed that that temperature can be achieved by running an electrical current across a 0.1mm-thick copper mesh or thermoelectric heater, powered by a small battery.
The current prototypes (pictured above) include a 9-volt battery, which would provide enough power to heat the mask for a few hours and would cool the air before it is inhaled.
“Of course, we need to be mindful of the safety and comfort of mask users,” Faucher said. “The air will be cooled after viral inactivation to make the mask comfortable and safe to use.”
The researchers were able to enhance the efficiency of virus deactivation by taking advantage of the breath to create a type of reactor known as a reverse-flow reactor.
As the person wearing the mask breathes in and out, the air flow continually reverses, allowing any viruses in the mask to pass over the mesh many times and making it more likely that they will be deactivated. Purified air flows out of vents on both sides of the mask.
LG has previously revealed a battery powered facemask with in-built fans while another MIT team constructed a silicone mask with reusable N95 filters to reduce waste.