Development of an embossed nanofiber hemodialysis membrane for improving capacity and efficiency via 3D printing and electrospinning technology

A three-dimensional (3D) pattern was fabricated using a 3D printer to develop a hemodialysis nanofiber membrane with an embossed structure for portable or wearable hemodialyzers. The membrane of the embossed structure had a much larger surface area than that of the planar membrane structure. The high-flux hemodialysis membrane was prepared using a poly(methyl methacrylate)-graft-poly(dimethylsiloxane) (PMMA-g-PDMS) copolymer and polyamide 6 (PA6). The PMMA-g-PDMS copolymer is an organic-inorganic hybrid material in which the nanofiber diameter was controlled under 0.437 mu m with a surface layer thickness of 50 (+/- 20) mu m. The polyamide 6 (PA6) nanofiber membranes were made with fibers 0.072 mu m in diameter with a 0.14 mu m pore size. This PMMA-g-PDMS/PA6 nanofiber hemodialysis membrane was modified for enhanced dialysis efficacy, and the modified membranes were evaluated based on clearance of saline and small molecules. Esterification and crosslinking reactions resulted in anionic hydrophilic hemodialysis membranes, and the fouling resistance is due to esterification of carboxylic acid groups (-COOH) of sodium alginate with hydroxyl groups (eOH) of polyethylene glycol, which generated a negatively charge surface. Thereby, repulsive electrostatic forces might be generated between the negatively charged blood cells and negative surface membrane. The water contact angle showed that the membrane hydrophilicity increased from 129 and 90 degrees to 50 degrees, and the total fouling parameter decreased to 0.112. The fouling resistance was enhanced due to the negatively charged membrane surface. Membrane contamination was measured by protein adhesion using a surface potential difference based on fluorescent whitening with zeta potential analysis, and the efficiency of creatinine removal was increased using a beta (beta-cage) zeolite.