Optimization of Ag-TiO₂ nanocomposite at a low toxicity dose as a self-virucidal disinfectant against COVID-19

Self-virucidal Ag-TiO₂ nanocomposites at low toxicity dose could be a viable solution to reduce the risks posed by SARS-CoV-2 infection and excessive usage of disinfectants. We synthesized an Ag-TiO₂ nanocomposite suspension in a simple, low energy consumption, eco-friendly, one-pot process. PVP and SDS were used in a 3:1 ratio as co-stabilizers, resulting in a uniform size with high stability. The nanocomposite characterization used UV–Vis spectroscopy, high-resolution transmission-electron-microscopy equipped with an energy dispersive X-ray spectroscope (HR-TEM, EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). We determined the virucidal efficacy against SARS-CoV-2 by following ASTM E1052-20. The cytotoxicity test followed ISO 10993–5:2009. At high doses (50 ppm), the Ag-TiO₂ nanocomposite suspension showed ≥ 99.96% virucidal efficacy within 1 min, damaging the viral genome. At a low dosage (0.8 ppm), the viral infectivity was reduced by 99.86% within 24 h and minimized cytotoxicity. The viral protein had denatured, while the viral genome remained intact. The results suggest that the Ag-TiO₂ nanocomposite can be used in a more eco-friendly and safer manner as a potent broad spectrum virucidal disinfectant, offering broad action against unspecified targets (all virus proteins, not just the spike proteins), which could be helpful in all SARS-CoV-2 variants of concern.