Face Masks, What Type Should You Wear?

According to Scientific American, the Indiana Centre for Regenerative Medicine and Engineering have developed a material which renders infectious particles harmless when passed by hands to the front of masks. 

The team have researched electroceutical materials that wirelessly generate electric fields across the surface of the fabric.  These fields then disrupt the behaviour of bacterial viruses on cloth. 

The polyester material is printed with alternating spots of silver and zinc resembling polka dots.  They are 1-2 mm wide and spaced 1 mm apart.  When the electroceutical material is dry, it functions as an ordinary fabric, but when it gets dampened with saliva, vapour from a coughed up droplet or other bodily fluids, ions in the liquid trigger an electrochemical reaction. 

The silver and zinc then generate a weak electric field that kills the pathogens on the surface.  The researchers co-developed this material with the biotechnology company Vomaris Innovations in 2012.  Last year they were able to show that the technology could be used to treat bacterial biofilms in wounds.

They then tested existing material on different coronavirus strains, which cause respiratory illness in pigs and also an unrelated pathogen called lentivirus.  They reported that the electroceutical fabric destabilised both viruses, leaving them unable to infect cells.  They did this by placing liquid solution containing viral particles on the electroceutical fabric and a polyester control fabric without metal dots.  After the droplets were fully absorbed, and the samples had rested for one to five minutes, the researchers recovered viral particles from both fabrics and tested whether they could infect the types of cells they typically target. 

They were able to recover 44% of the particles from the electroceutical fabric samples that had rested for one minute and found that they were inactivated.  They were also able to retrieve 24% from samples that had rested for five minutes.  It has not been specifically tested with SARS-CoV-2 but from the two viruses studied they have hope that the fabric could be used widely. 

Metal dots are not the only potential approach.  Paul Leu from the University of Pittsburgh and his colleagues are developing a textile coating that repels bodily fluids, proteins and bacteria.  It also repels one strain of adenovirus that causes respiratory illness and another that causes conjunctivitis.  They have yet to test SARS-CoV-2 because of its biosafety issues but are going to test with differing coronaviruses.

Leu is confident that his repellent even after ultrasonic washing and scraping with a razor blade, could make PPE safer for wearers.  He also suggested it could be used on hospital bed linens, drapes and waiting room chairs. 

However, at this stage they have not tested it on single use mask or N95 mask. It is possible that the coating could damage them and currently is only intended for reusable fabrics. He suggests that it could work well for cloth masks such as those worn by the general public.

The London General Practice has consistently advocated the wearing of face masks by all.  As previously analogised, if we were all safe drivers there would never be an accident.

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