Photothermal Electrospun Nanofibers Containing Polydopamine-Coated Halloysite Nanotubes as Antibacterial Air Filters

Antibacterial air filter media offer an important solution to indoor air pollution from bioaerosols, which pose a serious threat to global public health. In this study, we introduced an antibacterial air filter based on nanofibers functionalized with a photothermal agent, which deactivates bacteria upon near-infrared (NIR) irradiation. Halloysite nanotube (HNT) clay nanoparticles coated with polydopamine (PDA), which heat up when exposed to NIR light, were utilized as photothermal agents to be incorporated into polyacrylonitrile (PAN) nanofibers. The resulting PAN/HNT-PDA nanofibers reached 102 °C after 2 min of NIR irradiation and physically destroyed Staphylococcus aureus (S. aureus) cells that were in contact with the nanofibers. In a simulated air filtration test system, photothermal nanofibers demonstrated a bioaerosol filtration efficiency of 99.97% and a quality factor of 0.14 Pa^-1. 10⁷S. aureus cells captured on the nanofibers were killed via a 10 min NIR-light irradiation, whereas the light-activated antibacterial properties of the nanofibers were maintained over 5 bioaerosol flow/NIR-treatment cycles. The photothermal agent-containing electrospun nanofibers presented here have a strong potential for aerosol removal as light-activated antibacterial air filters.