Bifunctional Electrospun PAN/ε-Polylysine Composite Membranes for High-Efficiency PM2.5 and PM10 Filtration with Antimicrobial Protection.

Airborne particulate matter (PM2.5 and PM10) and bioaerosols pose synergistic threats to respiratory health, necessitating advanced filtration technologies that simultaneously address particulate and microbial contamination. We report a bifunctional multilayer composite air filter membrane fabricated by electrospinning polyacrylonitrile (PAN) nanofibers (average diameter 609 ± 88 nm) onto nonwoven substrates integrated with ε-poly-l-lysine (ε-PL) antimicrobial coating. Optimized electrospinning conditions (10 wt % PAN, 15 min deposition) yielded uniform, bead-free nanofibers achieving exceptional filtration efficiencies of 99.39 ± 0.09% for PM2.5 and 99.50 ± 0.16% for PM10, while maintaining low pressure drop (175 ± 5 Pa) suitable for respiratory applications. The ε-PL coating, immobilized via PVA-mediated adhesion, transformed the hydrophobic spunbond surface to hydrophilic (contact angle reduced from 108° to 48°) and conferred potent antimicrobial activity. Time-kill assays demonstrated concentration-dependent bactericidal effects, with 10 mg/mL ε-PL achieving complete bacterial eradication (>6-log reduction) within 24 h against both Gram-positive and Gram-negative pathogens. Comparative analysis revealed superior performance over commercial multilayer masks (66-98% efficiency for PM2.5; 66-98% efficiency for PM10), despite lower basis weight (94.01 ± 1.95 g/m2). The quality factor analysis confirmed optimal balance between high filtration efficiency and breathability at 15 min electrospinning time. These dual-functional membranes demonstrate the synergistic integration of high-efficiency particulate filtration across multiple size fractions with antimicrobial protection, offering a promising platform for personal protective equipment, HVAC systems, and healthcare air purification applications where simultaneous removal of coarse and fine airborne particles and pathogen inactivation is critical.