Silver and copper-based spray coatings have proven to eliminate the growth of some of the most dangerous bacteria in air filtration systems, significantly reducing the risk of airborne bacterial and viral infections.
In a paper published in the journal Materials Chemistry and Physics, the researchers behind these findings explain that they tested various spray coatings of silver (Ag2O), copper (CuO) and zinc (ZnO) oxides. They noticed that both the Ag2O and CuO compounds used had a total antiviral activity greater than 99%, with the Ag2O filter extract also demonstrating a complete prevention of targeted bacterial growth throughout the 24-hour incubation period measured by the study.
In the researchers’ view, these findings could prove relevant in preventing the spread of a wide number of respiratory infections. However, they focused on the antimicrobial properties of metal oxide particles against two specific respiratory pathogens: Streptococcus pneumoniae and Pseudomonas aeruginosa.
“S. pneumoniae and P. aeruginosa are considered among the top five bacterial pathogens leading to death worldwide,” Mónica Echeverry-Rendón, co-author of the paper and a researcher at IMDEA Materials Institute, said in a media statement. “A. 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 linked to chronic infections in patients with cystic fibrosis and bronchiectasis.”
Echeverry-Rendón pointed out that air filtration is one of the most commonly used methods to ensure indoor air quality. Its efficacy has been well-established in capturing airborne pathogens and ensuring adequate air sterility in controlled environments. However, after long-term use, microorganisms harmful to human health, such as fungal spores and bacteria can accumulate and even thrive within untreated filters.
During the last two decades, several species of bacterial spores have been detected in such environments, including Propionibacterium, Staphylococcus and Legionella. A wide variety of harmful fungus species have also been identified, such as Aspergillus, Penicillium and Cladosporium.
After an extensive preparation period, the oxide powders utilized in the study were sprayed directly onto the filter surfaces, which were then characterized and biologically assessed. The positive results obtained keep the scientists involved hopeful and encourage further study on the subject to learn more about the mechanisms between particles and microorganisms.
