The new cloth mask destroys 99.9% of bacteria, viruses in one hour of sunlight, according to science

A reusable cotton face mask has been created by researchers that they believe can kill up to 99.99 percent of bacteria and viruses within 60 minutes of daylight exposure.

Nanoscale aerosol particles, such as those released by a cough or sneeze, may be removed by face masks made of various cloth materials, potentially helping to reduce the spread of diseases, including COVID-19.

According to the study published in the journal ACS Applied Materials & Interfaces, however, live bacteria and viruses on the surface of the mask could still be contagious.

A new cotton fabric was created by researchers from the University of California, Davis in the US to release reactive oxygen species (ROS) when exposed to daylight, killing microbes attached to the surfaces of the fabric while being washable, reusable, and safe for the wearer.

During their lunch hour outside in the sun, a person could disinfect their cloth mask or spend a longer period of time under office or building lights, which are much less intense than sunlight, they said.

By attaching positively charged chains of 2-diethyl aminoethyl chloride (DEAE-Cl) to regular cotton, the researchers made their antimicrobial fabrics.

In a solution of a negatively charged photosensitizer—a compound that releases ROS when exposed to sunlight modified cotton was then colored and attached to the DEAE chains by strong electrostatic interactions.

The team found that 99.9999 percent of bacteria introduced to the fabric within 60 minutes of daylight exposure were killed by a fabric made with a dye called rose Bengal as the photosensitizer and 99.9999 percent of T7 bacteriophage — a virus believed to be more resistant to ROS than other coronaviruses — were inactivated within 30 minutes.

Further testing showed that without losing its antimicrobial activity, the material could be hand-washed at least 10 times and constantly exposed to daylight for at least 7 days, the researchers said.

The fabric shows promise to make face masks and protective suits of reusable, antibacterial/antiviral material, they said.