New Surgical Mask Designed to Kill Viruses

During the severe acute respiratory syndrome (SARS) epidemic, images of people wearing protective surgical masks became normal in places that were most affected. Now, a team of researchers has taken on the task of improving these masks so that they are not only able to trap pathogens, but can kill them as well.

According to the Centers for Disease Control and Prevention (CDC), surgical masks are designed to be worn by healthcare workers over the nose and mouth to provide barrier protection against large respiratory particles and other droplets. However, they do not filter small particles from the air effectively or prevent these particles from entering around a mask’s edges, and are, therefore, not as effective as respirator-style masks at filtering out airborne particles. During the 2009 outbreak of a novel H1N1 influenza virus, the CDC responded to the public’s increased use of face masks in community settings as a way to decrease the risk of influenza infection; they noted that there was no data ensuring the effectiveness of this infection prevention method.

With flu season underway in the Northern Hemisphere, coupled with circulating colds and stomach viruses, the public’s use of surgical masks to limit exposure to pathogens continues. In a new study published in Scientific Reports, a team of researchers from the University of Alberta in Edmonton, Canada has released its findings on improvements they made to surgical masks to make them more effective at reducing the risk posed by aerosolized pathogens. Such masks, the authors noted, are often used when novel viruses arise and new vaccines are not available to prevent the spread of infection or when vaccines are in limited supply. In such situations, conventional surgical masks offer some level of protection, but respiratory droplets infected with a virus can persist on mask surfaces, and handling the mask can leave the wearer vulnerable to infection. “Surgical masks were originally designed to protect the wearer from infectious droplets in clinical settings, but it doesn’t help much to prevent the spread of respiratory diseases such as SARS or MERS or influenza,” explained study author Hyo-Jick Choi, PhD.

Dr. Choi and his team developed a universal, reusable virus deactivation system — a surgical mask with a sodium chloride salt coating along its main fibrous filtration unit. The authors explained that the salt coating on the fiber surface dissolves once exposed to aerosolized pathogens and recrystallizes during drying, destroying the pathogens. In their study, the researches exposed their mask to influenza virus, which has a smaller diameter than S. aureus, and found that their design, offering tightly sealed sides, showed remarkably higher filtration efficiency than a conventional mask. They observed that viruses captured on the salt-coated masks showed a more rapid infectivity loss than on untreated mask fibers. Furthermore, the masks were able to deactivate influenza viruses of different subtypes.

“Development of a universally applicable, low-cost, and efficient mechanism for virus negation is regarded as a major challenge in public health against general airborne biological threats,” the authors wrote. “Our salt-coated filter unit can promise the development of long-term stable, versatile airborne pathogen negation system, without safety concerns.”