Porous nanofiber/microparticles-structured membrane of polymyxin B modified poly(styrene-random-glycidyl methacrylate) by electrospray for endotoxin removal in blood purification

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Inspired by the kidney's renal glomerulus, a binary solvent mixture system of tetrahydrofuran (THF) and methanol was used to form porous nanofiber/microparticles (PNfMp) during electrospray technology. Poly(styrene-random-glycidyl methacrylate) (PSGM) was synthesized by atom-transfer radical polymerization as a supporting material for the electrospray process. During the electrospray process, THF, with a lower boiling point, evaporated first, forming the PNfMp of PSGM containing the nanoemulsified methanol with a higher boiling point. After the solidification of the PSGM, the nanoemulsified methanol evaporated, creating highly porous microparticles/nanofibers of PSGM. The Brunauer-Emmett-Teller (BET) surface area of the PNfMp-structured PSGM membranes reached 986.6 m2/g. We further investigated modifying the surfaces of the electrospun membranes with polymyxin B (PMB) through the epoxy groups of PSGM for endotoxin adsorption. The maximum adsorption capacity of endotoxin on the PMB-modified PSGM membrane with a PNfMp structure is approximately 3.1 EU/mg, which is much higher than that without a PNfMp structure, at 0.7 EU/mg. A filter packed with the PMB-modified PSGM membrane was constructed to remove endotoxin from human plasma. The removal efficiency reaches almost 100 % for 14 mL using 3.2 mg of the membrane at a flow rate of 1 mL/min. Our proposed method provides an ideal strategy to prepare PNfMp membranes for endotoxin removal in blood purification.