Airborne infection risk plummets in face of metal nanoparticle spray
As recent history proves, airborne respiratory infections are not to be trifled with. Now, a new sprayable coating applied to standard air filters might give us a leg up in the war against the pathogens that cause these diseases.
Measles. Influenza. SARS. MERS. Pneumonia. Think of a major infectious disease, and the chances are that it is spread by airborne pathogens. Currently, COVID-19 and TB are the world's deadliest infectious diseases, and both are transmitted through the air. So when it comes to tamping down the risk of disease spreading through populations, developing solutions that can knock infectious bugs out of the air is paramount.
That's why researchers in Spain teamed up with Spanish air filter manufacturer Venfilter to see if there was a spray coating that could improve the disease-fighting ability of commercially available air filters.
The research team experimented with three metallic compounds: silver oxide, copper oxide, and zinc oxide. From each, they created a spray containing nanoparticles of the compounds and applied that spray to the filters. They found that both the silver oxide and copper oxide sprays provide a greater than 99% antiviral activity, with the silver oxide spray also completely stopping bacterial growth during the 24-hour period examined in the study. They also found that the spray did not interfere with the effectiveness of the filters in doing their normal job of removing other particles from the air.
While the researchers feel that the coatings could be effective against a variety of airborne pathogens, for this study they focussed on two in particular: Streptococcus pneumoniae and Pseudomonas aeruginosa.
"S. pneumoniae and P. aeruginosa are considered among the top five bacterial pathogens leading to death worldwide," said study co-author Mónica Echeverry-Rendón. "S. pneumoniae is the major cause of community-acquired bacterial pneumonia, acute otitis media in children and non-epidemic meningitis. P. aeruginosa, meanwhile, is commonly associated with recurrent exacerbations associated with chronic infections in patients with cystic fibrosis and bronchiectasis."
We've already seen the antiviral effectiveness of metallic oxides in a bioactive glass, and in a heat-activated procedure designed to bust biofilms. We've even seen a type of light-activated foil meant to be used to increase the efficacy of HEPA air filters in destroying harmful bacteria. Like those advances, the new spray coating will also need a bit more development before it is commercially available.
"Although the achievements reached up to this point are very significant at a scientific level, there is still a long way to go before it will be possible to commercialize them at an industrial level." said Echeverry-Rendón. "Different aspects and further tests will need to be considered in future works … so that a complete characterization of coating effectiveness and filter performance, over time, and using real-size filter prototypes with sealed frames, can be carried out."
The current study has been published in the journal Materials Chemistry and Physics.
Source: IMDEA Materials Institute