Inhibition of Japanese encephalitis virus infection by biogenic catechin silver nanoparticles: An in-vitro study.

Background: The interaction of nanoparticles with microorganisms is an emerging field. Within this, an area that has been limitedly explored is the interaction of nanoparticles with viruses. Recently studies on silver nanoparticles (AgNPs) showed potent antiviral activity against HIV, HBV, influenza and dengue virus. However, synthesis of metallic nanoparticles involves physical and chemical approach utilizing toxic chemicals, which may hinder its application for human use. Therefore, development of novel ecofriendly nanoparticles is of great interest. In the present study, we synthesized green AgNPs with catechin as reducing agent. Catechin, a polyphenol being itself having antiviral propertymayenhance the efficiency of AgNPs. We evaluated biogenic catechin AgNPs against Japanese encephalitis virus (JEV), which is a major public health problem particularly in Asia. Methods & Materials: Green nanoparticles were synthesized by adding purified catechin intoAgNO3solution by following standard method. Standard circulating JEV strain JERG07 (Source: Human, 2007, Assam, India) was used. In vitro assays were done using VERO cell line. Cell viability assay for 2 fold diluted green AgNPs was done using MTT standard protocol assay. Cytopathetic effect (CPE) inhibition assay was performed with 1 Multiplicity of infection (MOI) of JEV. Cells were also observed daily under inverted microscope and were assigned a score based on appearance of CPE. Further, virus yield reduction assay was done to quantify the level of protection of nanoparticles treated both at pre & post JEV infection. Results: Transmission Electron Microscopy (TEM) analysis revealed formation of biogenic AgNPs within the size of 50nm. Maximum (100%) cell viability for green nanoparticles was observed in the range from 0.04g/ml to 5.85g/ml. Within thesamerange CPE inhibition assay also showed full protection against JEV. Further, virus yeild reduction assay showed reduction in plaques number in comparison to virus control in both pre & post JEV infection cells. Conclusion: The present study demonstrated the ability of catechin reduced biogenic AgNPs to prevent JEV infection by inhibition of virus attachment and post infection spread. Future studies should be focused on elucidating the mechanism of nanoparticle-virus interaction at cellular and microscopic level. [ABSTRACT FROM AUTHOR]