Antiviral and Nontoxic Dermal Iron Oxide Nanoparticle/Biopolymer Coatings for Cotton Fabric

In this study, hybrid coating systems comprising biopolymers (chitosan, N-succinyl chitosan, or sodium alginate, and sodium carboxymethylcellulose) and iron oxide nanoparticles (IONPs) were synthesized, and their antiviral activity against the coronavirus as well as their dermal toxicity in rats were evaluated. The hybrid systems were applied as coating surfaces with virucidal properties against the coronavirus. IONPs were synthesized by using the coprecipitation method, with TEM images revealing their crystalline structure and an average size of 5.6 nm. XRD analysis confirmed the predominance of magnetite in the nanoparticles. Zeta potential analysis assessed the suspension stability of the biopolymer-based antiviral solutions at different IONP concentrations (1.4, 2.8, and 4.1 mM). The hybrid systems were designed for coating cotton fabric, and SEM, EDS, and FTIR characterized the coated surfaces. Among the coatings, the N-succinyl chitosan-based (IONPs/NSC) coating showed the lowest iron ion release after 24 h compared to other polymers. The IONPs/NSC hybrid coating achieved 99% antiviral activity within 5 min of contact, and all coatings exhibited 99.9999% antiviral activity against coronavirus within 24 h, while being nontoxic to L929 fibroblast cells after 24 h of exposure. The acute dermal toxicity of the IONPs/NSC hybrid system was evaluated in accordance with OECD guidelines 402, demonstrating safety for topical use. For this, animals were treated with topical applications of increasing doses of IONPs/NSC (1.5, 5, 14, and 40 mg/kg), benzalkonium chloride (750 mg/kg, toxic standard), and saline or white nanoparticle (WN, control group or a polymeric solution without IONPs). Compared to the control group, no clinical or histological changes were observed for the IONPs/NSC groups during the 14-day observation period. Conversely, benzalkonium chloride induced erythema, edema, and histological alterations in rat skin. These coatings show promise for use on protective equipment, with the aim to mitigate the risk of epidemics or pandemics.