5 wt% of SN129. Figure 4 shows the dependence of
particle size and amount of Ag NPs on the antiviral activity FG-4592 chemical structure of the composites https://www.selleckchem.com/products/Vorinostat-saha.html against influenza A virus. The TCID50 ratios of viral suspensions treated with Ag NPs and Ag NP/Ch composites to untreated suspensions were used to gauge the antiviral activity of the materials. For all Ag NPs tested, the antiviral activity of the Ag NP/Ch composites increased with increasing amount of Ag NPs. No antiviral activity was observed with chitosan alone, showing that the antiviral activity of the composites was due to the bound Ag NPs. The effect of size of the Ag NPs in the composites was also observed: for similar concentrations of Ag NPs, stronger antiviral activity HTS assay was generally observed with composites containing smaller Ag NPs. This size effect was most prominent when less than 100 μg of Ag NPs was added to 1 mg of chitosan. No increase in antiviral activity was observed above 200
μg of Ag NPs per 1 mg of chitosan, irrespective of the size of the Ag NPs. Figure 4 Relationship between the anti-influenza virus activity of Ag NP/Ch composites and their composition. SN35 (square), SN65 (diamond), and SN129 (circle). Previous studies showed that Ag NPs have antiviral activity against influenza A virus [13, 14]. Although the mechanism of action has not been well investigated, it is likely that the antiviral activity of Ag NPs against several other types of viruses is due to direct binding of the Ag NPs to viral envelope glycoproteins, Janus kinase (JAK) thereby inhibiting viral penetration into the host cell [6, 8, 13, 30]. The effect of the size of Ag NPs on antiviral activity was usually observed, suggesting spatial restriction of binding between virions and Ag NPs [6, 8]. For the Ag NP/Ch composites, further spatial restriction due to the chitosan matrix would be expected to prevent or weaken the interaction between virions and Ag NPs. On the other hand, physical binding of virions to the composites could directly inhibit viral contact with host cells since the virus-treated composites were removed from the assay solution prior to infection of the host cells. When embedded Ag NPs could interact
with the virions, the interaction between the virions and the composites should increase with increased concentration of Ag NPs in the composites; this is supported by the experimental results on the relationship between the antiviral activity and the concentration of Ag NPs. The effect of the size of Ag NPs in the composites on antiviral activity suggests that influenza A virus interacted selectively with smaller Ag NPs, as previously reported for other types of viruses [6, 8]. However, the size dependence of free Ag NPs on antiviral activity against influenza A virus has not been studied. To obtain more effective Ag NP-embedded antiviral materials, detailed studies of the mechanism of antiviral action of both free and embedded Ag NPs are required.