Fabrication of silver nanowire coated fibrous air filter medium via a two-step process of electrospinning and electrospray for anti-bioaerosol treatment

Antimicrobial agent treatment is needed to prevent airborne infections due to microorganisms causing diseases. Silver nanowires (AgNW) have been increasingly used in air filters for their superior antimicrobial performance. In this study, AgNWs (115 nm in diameter, 4–50 µm in length) were electrosprayed on the surface of polyacrylonitrile (PAN) fibres that were obtained by electrospinning. Filtration efficiency of the AgNW-coated fibres was tested by aerosolizing and convectively delivering test bacteria and virus particles to the fibres. Then the particles filtered on the fibres were cultured to evaluate antibacterial and antiviral abilities. The overall filtration efficiency of the fibres increased from 92% to 96.5% (at 2.5 cm/s of air velocity) to 98.3–99.6% after AgNW coating for 30 min (areal density = 2.352 μg per 1 cm² of filter surface area), without affecting the pressure drop. The AgNW coating for 30 min significantly increased the antimicrobial efficiency to 98.0 ± 1.1% for Staphylococcus aureus (S. aureus), 95.2 ± 2.6% for Bacillus cereus (B. cereus), 93.7 ± 1.5% for Micrococcus luteus (M. luteus), and 72.5 ± 1.9% for bacteriophage MS2.