Electrospinning of PSF Microparticle-Containing Membranes

PSF beads (Sigma-Aldrich, Taipei, Taiwan) and polyethylene glycol (Sigma-Aldrich, Taipei, Taiwan) were mixed until homogenous in a 7:3 mixture of N,N-dimethyl formamide (DMF; Tedia, Fairfield, OH, USA) and dichloromethane (DCM; Mallinckrodt, St. Louis, MO, USA). Under ambient conditions, the resulting polymer solution was electrospun as a ‘shell solution’ with a ‘core solution’ comprised of polyethylene glycol (Sigma-Aldrich, St. Louis, MO, USA) and polyethylene oxide (Sigma-Aldrich, St. Louis, MO, USA, as described in previous works [22 (link),25 (link),34 (link)]. Briefly, the high voltage charge supply (You-Shang Co., Fongshan City, Taiwan) generated electrostatic force was set up at 4.5–7 kV also current sustained at 750 µA. The distance between the stainless-steel Co-axial spinneret and the rotating drum collector was 50 mm. The rotating drum collector spun at the speed of 100 ± 10 rpm (radius: 70 mm, 0.73 ± 0.07 m/s). After that, the PSF MTAMs were extracted and washed in double distilled water (ddH₂O), then air-dried. Using a scanning electron microscope, the microstructure characteristics of the PSF MTAMs were measured (SEM; Hitachi, Chiyoda City, Japan).