Salted Surgical Mask Deactivates Aerosol Viruses

A novel salt coating on the fiber surface of a surgical mask dissolves upon exposure to virus aerosols and recrystallizes during drying, destroying the pathogens.

Developed by researchers at the University of Alberta and Kyung Hee University, the universal, reusable virus deactivation system is based on common sodium chloride salt that coats the fibrous filtration unit of the surgical mask. When an aerosol droplet carrying the influenza virus contacts the treated filter, the droplet absorbs the salt on the filter. The virus is exposed to increasing concentrations of salt as the droplet evaporates, suffering fatal physical damage when the salt returns to its crystalized state.

In a series of experiments, viruses captured on the salt-coated filters show a rapid decrease in infectivity compared to a more gradual decrease when placed on bare filters. The salt-coated filters proved especially effective in deactivating influenza viruses, regardless of subtypes and even following storage in harsh environmental conditions. The researchers suggest that the technique can be applied in broad-spectrum, airborne pathogen prevention devices in preparation for combatting epidemic and pandemic respiratory diseases. The study was published on January 4, 2017, in Scientific Reports.

“Our salt-coated filter unit can promise the development of long-term, stable, versatile airborne pathogen negation systems, without safety concerns,” said Professor Hyo-Jick Choi, PhD, of the University of Alberta department of chemical and materials engineering. “We believe that salt-recrystallization based virus deactivation system can contribute to global health by providing a more reliable means of preventing transmission and infection of pandemic or epidemic diseases and bioterrorism.”

Past experiences with severe acute respiratory syndrome (SARS), H1N1 swine influenza, and Middle East respiratory syndrome (MERS) indicate that surgical masks are widely adopted by the public as a personal protective measure, despite an ongoing controversy on their effectiveness. However, in the lack of a system to deactivate the collected pathogens, safety concerns naturally arise about secondary infection and contamination from virus-laden filter media during utilization and disposal. The main alternative, the N95 respirator, requires training prior to use, must be expertly fitted to address the risk of face seal leakage, and must be disposed of as biohazard.