Graphene oxide nanoparticles inhibit H9N2 influenza A virus infectivity by destroying viral coat proteins.

Nanoparticles have gained attention as potential antiviral agents, but the effects of graphene oxide nanoparticles (GONPs) on influenza virus remain unclear. In this study, we evaluated the antiviral activity of GONPs against influenza virus strain A/Hunan-Lengshuitan/11197/2013(H9N2). Our results show that GONPs with a diameter of 4 nm exerted an antiviral effect, whereas those with a diameter of 400 nm had no effect. Treatment with 4-nm GONPs reduced viral titers by more than 99% and inhibited viral nucleoprotein expression in a dose-dependent manner. We also confirmed that 4-nm GONPs inhibited the infectivity of H9N2 in MDCK cells. A transmission electron microscopic analysis revealed morphological abnormalities in the GONP-treated virus, including the destruction of the envelope glycoprotein spikes and an irregular shape, suggesting that GONPs cause the destruction of the viral coat proteins. Our results highlight the potential utility of GONPs in the prevention and treatment of viral infections, especially those of emerging and re-emerging viruses.