Might the addition of copper to facemasks help reduce the risk of catching or spreading the coronavirus that causes the pandemic disease Covid-19?

The debate over whether we should be wearing facemasks is gradually settling on the side of caution. Many researchers have pointed out that we have not adopted facemasks as a strategy to any significant degree for respiratory pathogens previously. However, the current outbreak which at the time of writing has killed more than 600,000 people when outbreaks seems very different with so many people who are asymptomatic able to spread the disease before they know they are a carrier. A simple measure would be to wear a covering over one's nose and mouth to preclude the expulsion of infectious droplets into the air or on to surfaces. Researchers have already shown that a two-ply tightly woven cotton material sandwiching a layer of chiffon or silk to add an electrostatic barrier can reduce the passage of 98 percent of droplets.

Now, researchers at Indiana University Purdue University Indianapolis's Integrated Nanosystems Development Institute think we could add an additional defence to such a mask in the form of metallic copper oxide nanoparticles. Copper has been used throughout history for its germicidal properties although until the discovery of microbes its positive effects on health in this regard were inexplicable. Any virus that impinges on a copper surface will be disabled instantaneously, IUPUI's Mangilal Agarwal points out. He suggests that many consumer-level masks, as opposed to clinical grade masks do not have a sufficiently tight weave. A tighter weave or the addition of other fabric layers can make a mask less comfortable to wear as well as making it harder for the wearer to breathe. Such characteristics will have a negative effect on compliance while facemasks are not mandated through law.

The IUPUI researchers suggest that embedded copper oxide nanoparticles would add a kill layer so even if droplets do travel from one surface of the mask to the other with the attendant risk of infection that would imply, the copper will disable the virus en route. The team has pointedly turned its attention to this application of their earlier work to make lighter, stronger, and cheaper composites with the ultimate aim of offering the general public a wearable alternative to the expensive masks that healthcare workers are often required to wear.

"To make any fabric into a mask or filter, we have to provide the nanostructure, and we can put that nanostructure on a roll-to-roll printing machine with the fibers at nanoscale," Agarwal explains. "We are using electrospinning, using the electric field to spray the nanofibers on to the fabric."

David Bradley