SnO₂NPs as a Nontoxic Antiviral Agent for Designing Protective Masks against Human Coronavirus Infection

The COVID-19 pandemic has created a need to develop protective textiles that reduce the infection of SARS-CoV-2, mainly via face masks. The key issue in designing protective textiles is the functionalization with antiviral agents. This report presents tin oxide nanoparticles (SnO₂NPs) as a novel, efficient antiviral agent against human coronavirus HCoV 229E due to blocking virus entry, attachment, and penetration into MRC-5 cells and nontoxicity. SnO₂NPs were obtained by sodium stannate hydrolysis and have a 3 nm diameter, a cubic structure, and a zeta potential of -28.8. SnO₂NPs were applied to functionalize a protective face mask made of silk fibroin. Polydopamine was applied to immobilize the particles. SnO₂NPs have a negative potential and enhance silk fabric hydrophobicity, which is crucial for antiviral properties. The mask functionalized with SnO₂NPs reveals very good antiviral properties and antibacterial activity against Gram-positive and -negative bacteria. Silk fabric functionalized with SnO₂NPs retains the silk fibroin β-sheet structure, is nontoxic, noncorrosive to human skin, and reveals high thermophysiological wear comfort.The highest filtration efficiency is obtained for the 3-layered mask (60%), while breathing resistance, sufficient for the FFP3 mask, was achieved for the 1-layered mask (maximum allowable breathing of 100 and 300 Pa, respectively, for 30 L/min and 95 L/min inhale and 300 Pa for an exhale flow rate of 160 L/min). SnO₂NPs can be useful in developing advanced antiviral textile materials to control virus spread and future pandemics.