Silver-Zinc oxide nanocomposites: a green approach to mitigate herpes simplex virus type 1 challenges

Herpes simplex virus type 1 (HSV-1) remains a significant global health challenge due to its high prevalence, recurrent infections, emergence of drug-resistant viral strains, and adverse effects associated with conventional antiviral therapies. In this study, silver-zinc oxide nanocomposites (Ag-ZnONPs) were synthesized using Nigella sativa extract and evaluated for antiviral activity against HSV-1 alongside ZnONPs, AgNPs, and calcined Ag-ZnONPs (Ag-ZnONPs-K). Characterization confirmed nanoparticle formation with sizes of ~ 35-50 nm and zeta potentials ranging from - 15.5 to - 25.5 mV. Cytotoxicity assays showed CC₅₀ values of 700 µg/mL (ZnONPs), 35 µg/mL (AgNPs), and 80 µg/mL (Ag-ZnONPs-K), while Ag-ZnONPs showed no cytotoxicity within the tested range. In post-treatment assays, Ag-ZnONPs achieved 95% viral inhibition at 120 µg/mL (SI = 12), comparable to ZnONPs (97% at 300 µg/mL, SI = 13) and higher than AgNPs (83% at 25 µg/mL). These results demonstrate strong in vitro antiviral activity of Ag-ZnONPs against HSV-1, particularly in post-infection conditions.