Ahmed H. Albariqi

Background: Viral infections represent a major challenge in modern medicine, including diseases caused by human papillomavirus (HPV), cytomegalovirus (CMV), and rotavirus, which are among the most prevalent viral pathogens. The rapid transmission and high mutation rates of these viruses contribute to substantial health burdens and socio economic consequences. Silver nanoparticles (Ag NPs) and titanium dioxide nanoparticles (TiO₂-NPs) are effective antiviral agents. The major objective of this investigation was to measure the antiviral activity of titanium dioxide nanoparticles (TiO₂-NPs) and green-produced silver nanoparticles (Ag NPs) against rotavirus, HPV, and CMV. Methods: UV-Vis spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) were used to characterize the nanoparticles. Cytotoxicity and antiviral activity were evaluated using a crystal violet assay in infected cell cultures. Results: The main findings indicate that both Ag NPs and TiO₂-NPs exhibited pronounced antiviral activity against HPV, CMV, and rotavirus. Ag NPs exhibited strong antiviral activity, with lower IC₅₀ values against HPV and CMV; however, this effect was associated with lower cytotoxic concentration (CC₅₀) and selectivity index (SI) values, indicating higher cytotoxicity. In contrast, TiO₂-NPs demonstrated a favorable safety profile, as indicated by higher CC₅₀ value particularly against CMV (863.90 µg/mL) and rotavirus (386.84 µg/mL)—and low cytotoxicity toward host cells—highlighting their strong antiviral selectivity and therapeutic potential. Conclusions: Overall, these findings suggest that, while Ag-NPs possess strong antiviral efficacy, TiO₂ NPs offer a more balanced combination of antiviral effectiveness and biosafety and may therefore be more promising candidates for antiviral applications.