This hypothesis was proposed by Zodrow et al. to explain the antiviral property of Ag NPs for bacteriophage MS2 and by De Gusseme et al. in response to MNV-1 exposed to Ag NPs.159,164 Moreover, Ag2S nanoclusters (NCs) with diameters of 2.5 and 4 nm showed effective inhibition of PEDV replication in Vero cells via inhibition of the synthesis of viral negative-strand RNA and of virus budding from the cells, but not by preventing their anchorage on cell membranes or their intracellular penetration.