UC assistant professor Patrick Guerra's work with silk moths inspired his research into the best masks to address the COVID-19 pandemic. Credit: Joseph Fuqua II/UC Creative

With personal protective equipment still in short supply, researchers at the University of Cincinnati examined what common household fabrics might work best as a face covering.

Next to a single-use N95 respirator or surgical mask, UC found the best alternative could be made by a hungry little caterpillar. Silk face masks are comfortable, breathable and repel moisture, which is a desirable trait in fighting an airborne virus.

Perhaps best of all, silk contains natural antimicrobial, antibacterial and antiviral properties that could help ward off the virus, said Patrick Guerra, assistant professor of biology in UC's College of Arts and Sciences.

Studies have shown that copper, in particular, can kill bacteria and viruses on contact. And that's where the little caterpillars have their own superpower, Guerra said.

"Copper is the big craze now. Silk has copper in it. Domesticated silk moths eat mulberry leaves. They incorporate copper from their diet into the silk," Guerra said.

Many health care providers wear a surgical mask in combination with an N95 respirator. The outer covering helps prolong the life of the N95 respirator by keeping it clean. Guerra, whose wife, Evelyn, is a medical doctor, said silk might be an especially good choice for this outer cover as they perform similarly to surgical masks that are in short supply.