Commercial metal-based nanocolloids--lack of virucidal activity against ECBO virus

Metallic nanoparticles, mainly silver ones, have been widely used as antibacterial agents, and some studies shown they also exert direct antiviral activity against both enveloped and non-enveloped viruses. The objective of this study has been to evaluate the virucidal activity of commercial silver, gold, copper and platinum nanocolloids, recommended by the manufacturer as antimicrobials, against the ECBO virus, according to Polish Standard PN-EN 14675:2006. The highest experimentally observed decrease in the viral load was 0.875 log, which--when contrasted with the reduction in virus titre of at least 4 log expected from disinfectants--indicates that none of the analyzed nanocolloids had a disinfectant power towards the ECBO virus under the conditions defined by the standard.