Radio Frequency Heating of Washable Conductive Textiles for Bacteria and Virus Inactivation

Abstract

The ongoing COVID-19 pandemic has increased the use of single-use medical fabrics such as surgical masks, respirators, and other personal protective equipment (PPE), which have faced worldwide supply chain shortages. Reusable PPE is desirable in light of such shortages; however, the use of reusable PPE is largely restricted by the difficulty of rapid sterilization. In this work, we demonstrate successful bacterial and viral inactivation through remote and rapid radio frequency (RF) heating of conductive textiles. The RF heating behavior of conductive polymer-coated fabrics was measured for several different fabrics and coating compositions. Next, to determine the robustness and repeatability of this heating response, we investigated the textile’s RF heating response after multiple detergent washes. Finally, we show a rapid reduction of bacteria and virus by RF heating our conductive fabric. 99.9% of methicillin-resistant Staphylococcus aureus (MRSA) was removed from our conductive fabrics after only 10 min of RF heating; human cytomegalovirus (HCMV) was completely sterilized after 5 min of RF heating. These results demonstrate that RF heating conductive polymer-coated fabrics offer new opportunities for applications of conductive textiles in the medical and/or electronic fields.

Laser-Induced Graphene Capacitive Killing of Bacteria

“…Graphene is a two-dimensional (2D) hexagonal lattice of sp 2 carbon atoms that are covalently bonded within two planar directions . In addition to its high thermal and electrical conductivity, flexibility, and mechanical strength, graphene has an exceptionally high surface area (e.g., ∼2600 m 2 /g) and intrinsic theoretical capacitance (21 μF/cm 2 ). − These properties perfectly poise this carbonaceous nanomaterial to be used within a broad array of applications ranging from electronics − (e.g., supercapacitors) and biotechnology to environmental technology − (e.g., renewable construction materials). − Within the spectra of environmental technology, examples of graphene derivatives have been shown to be antibacterial by many researchers over the years . The potency of graphene-based materials is especially true in the presence of an applied voltage as exemplified by laser-induced graphene (LIG). , However, the exact mechanism for the antibacterial activity such as the physical destruction of the cell membrane via direct contact of the bacteria with the surface structure/texture chemical microbial toxicity such as oxidative stress, or electrical effects of LIG or other graphene-based materials remains ambiguous and can be attributed to any combination of the various mechanisms.…”

Rapid In Situ Thermal Decontamination of Wearable Composite Textile Materials

“…For example, isolation gownsthe second most used PPE after glovesprotect the body from surface contaminants and are typically discarded after use; however, reusable isolation gowns have been shown to provide comparable protection to single-use isolation gowns while being more cost-effective and environmentally friendly. – Similarly, reusable masks can slow PPE pollution and alleviate supply chain issues, with reusable alternatives typically made from cotton-based fabrics with varying levels of filtration efficiency . Some fabrics have even been engineered to possess antiviral and antimicrobial properties. – However, all of these approaches either trap virions and other contaminants on the PPE material itself without inactivating them, allowing for an increased probability of fomite-mediated transmission of viruses, or require minutes to hours to achieve inactivation.…”

“…However, among these methods, UV irradiation cannot effectively decontaminate within the crevices and folds of a material; the combination of high temperatures and moisture involved in steam sterilization can degrade delicate PPE; and chemical disinfectants can leave harmful residues. Alternatively, dry heat decontamination is accessible and scalable, and it reduces virus viability without compromising the integrity of PPE, but the process remains slow and the PPE is typically doffed and placed into external heating infrastructure (e.g., an oven). , …”

“…Similarly, a layer of graphene was deposited onto a mask for use with a battery to provide portable Joule heating for the inactivation of viral contaminants . Beyond the use of integrated heat-generating elements for decontamination, heat generation in wearables in general presents a promising approach, especially as functional textiles have gained increasing interest . Strategies for heated wearables have been developed using electrically conductive textiles; for example, conductive fabrics and threads can be transformed into sewable and weavable electric heaters. , Wearable heaters have also achieved localized heating through graphene-based electrothermal materials, as well as thermofluidic actuation with phase-change fluids .…”

“…Alternatively, dry heat decontamination is accessible and scalable, and it reduces virus viability without compromising the integrity of PPE, but the process remains slow and the PPE is typically doffed and placed into external heating infrastructure (e.g., an oven). 23,30 Recent methods of dry heat decontamination have focused on integrating heat-generating elements into the PPE material itself. Nanomaterials, such as graphene, molybdenum disulfide (MoS 2 ), and titania (TiO 2 ), have been embedded into material layers to perform localized photothermal heating for the inactivation of viral and bacterial contaminants.…”