Co-existing "spear-and-shield" air filter: Anchoring proteinaceous pathogen and self-sterilized nanocoating for combating viral pandemic.

Infectious pollutants bioaerosols can threaten human public health. In particular, the indoor environment provides a unique exposure situation to induce infection through airborne transmission like SARS-CoV-2. To prevent the infection from spreading, personal protective equipment or indoor air purification is necessary. However, it has been discovered that the conventional filter can become contaminated by pathogen-containing aerosols, meaning that advanced filtering and self-sterilization systems are required. Here, we fabricate a multilayered nanocoating around the fabric using laponite (LAP) with Cu2+ ions (LAP-Cu2+ nanocoating) two contradictory functions in one system: trapping proteinaceous pathogens and antibacterial effect. Due to the strong LAP-protein interaction, albumin and spike protein (S-protein) are trapped into the fabric when proteins are sprayed using a nebulizer. The protein-blocking performance of the nanocoated fabric is 9.55-fold higher than bare fabric. These trapping capacities are retained after rinsing and repeated adsorption cycles, showing reproducibility for air filtration. Even though the protein-binding occurred, the LAP-Cu2+ fabric indicates antibacterial effect. LAP-Cu2+ fabric has an equivalent air and water transmittance rate to that of bare fabric with a stability under physiological environment. Therefore, given its excellent "Spear-and-shield" functions, the proposed LAP-Cu2+ fabric shows great potential for use in filter and masks during the viral pandemic.