An adhesive plastic film composed of silver-silica nanoparticles has been tested to be effective in removing 99.84% of SARS-CoV-2 (novel contagious coronavirus) if being exposed for a period of two minutes. This plastic film can be used to protect readily exposed surfaces like door handles, handrails, elevator panels, ATM machines etc. against COVID-19.
A Brazilian company, Promaflex has manufactured the film by incorporating silver and silica nanoparticles into the polyethylene-based primary plastic structure. This technology has been developed by Nanox, a São Paulo based enterprise, by collaboration with São Paulo Research Foundation. The efficiency of this novel plastic film against COVID-19 has been tested at Biosafety Level-III certified laboratories of University of São Paulo’s Biomedical Sciences Institute (ICB-USP). The results revealed that the novel designed plastic film has the potential to efficiently eliminate 99.84% of viruses after two minutes of exposure. Lucio Freitas Junior, research scientist at ICB-USP stated, “the technical standard governing measurement of antiviral activity on plastic and other non-porous surfaces, ISO 21702, requires demonstration of this capability within four hours. The plastic film with silver-silica nanoparticles did so far sooner, and its virucidal action increased over time.”
The tests conducted at the laboratory for analyzing the protective strength of this film against viral strains were in accordance with the standards devised by International Standardization Organization (ISO) i.e. ISO 21702:2019. Samples of the plastic film containing silver-silica nanoparticles were compared with those lacking it. Both the samples were exposed to SARS-CoV-2 for different durations. After the specified exposure time, viral specimens were exposed to Vero cells derived from African monkey’s kidney tissues which are extensively used for microbial culturing. The purpose was to monitor the infection and duplication rate of SARS-CoV-2 after its contact with the nanoparticles based plastic film. The final results obtained depicted a 100% curtailment in SARS-CoV-2 duplicates after a contact time of two minutes.
“The silver-silica nanoparticles are added to the polyethylene during its production, so the film’s antimicrobial action persists throughout its working life,” said Luiz Gustavo Pagotto Simões, CEO of Nanox. The manufacturers recommend that this plastic film can be used for three months and needs to be replaced after this period, as it may wear out due to inordinate viral exposure.