Inhibition of viral infection via adsorption-driven physical sequestration by natural illite: A sustainable, broad-spectrum antiviral material

초록

The increasing risk of airborne viral transmission, driven by various common aerosol-transmissible respiratory pathogens including endemic SARS-CoV-2, has intensified the need for sustainable antiviral materials suitable for integration into environmental infection control technologies. This study investigated the broad-spectrum antiviral activity of illite, a naturally occurring mica-type clay mineral, against diverse RNA and DNA viruses, including both enveloped and non-enveloped types. Illite was evaluated against 12 viral species under short-term vortexing and long-term shaking conditions. Illite effectively reduced the detectable infectivity for all tested viruses, regardless of genome type or envelope status. Specifically, measles virus and human respiratory syncytial virus were the most susceptible, whereas porcine epidemic diarrhea virus was the least susceptible. No antiviral activity was detected in illite particle-free supernatants, indicating the necessity of direct interfacial interactions between viral particles and illite surfaces and confirming the absence of any active cytotoxic or biocidal leaching. Field emission scanning electron microscopy analysis indicated that herpes simplex virus type 1 particles adhered to the surfaces of illite. The antiviral activity was likely associated with physicochemical adsorption mediated by negatively charged sites on the illite structure, such as planar and frayed-edge sites, which may contribute to electrostatic interactions with positively charged viral regions. These findings suggest illite as a promising passive, mineral-based antiviral tool for applications such as air filtration and surface coatings. Although this work was limited to laboratory-scale studies, the potential biological safety and broad-spectrum activity of illite warrant further investigation to improve environmental hygiene and public health resilience.

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