High-performance and hemocompatible zeolite-modified PP/PU dialysis membranes for uremic toxin removal

The development of hemodialysis membranes capable of simultaneously achieving efficient toxin removal and excellent hemocompatibility remains a major challenge. In this study, a novel dual-layer nanofibrous dialysis membrane was fabricated by combining a solution-electrospun polyurethane-oleic acid-polyethylene glycol (PU-OLE-PEG) top layer with a melt-electrospun polypropylene/zeolite (PP/Zeo) bottom layer. The PU-OLE-PEG layer was designed to enhance hydrophilicity and blood compatibility, while the PP/Zeo layer provided selective adsorption of uremic toxins. The resulting membranes exhibited a molecular weight cut-off of 22-25 kDa, enabling the selective removal of middle-molecular-weight toxins while retaining essential proteins. The 10PP/Zeo-Zeo-ME-PU-OLE-PEG-SE membrane demonstrated the highest adsorption capacity for creatinine (47 ± 5.3 mg g^-1) and removal efficiencies of 58 ± 5.6% for urea, 65 ± 6.5% for creatinine, and 71 ± 6.8% for β2-microglobulin (β2-MG). Under in vitro simulated dialysis conditions, high recovery of bovine serum albumin (BSA, 98 ± 9.5%) was achieved, indicating effective preservation of valuable proteins. Hemocompatibility studies revealed hemolysis ratios below 1%, markedly reduced protein adsorption (0.0023 ± 0.004 mg mL^-1), low thrombin-antithrombin complex formation, prolonged activated partial thromboplastin time (35.8 ± 3 s), and minimal platelet adhesion. Furthermore, the membranes exhibited excellent cytocompatibility, with cell viabilities exceeding 90%, favorable cell attachment. These findings demonstrate that the synergistic integration of a hemocompatible PU-OLE-PEG layer and a zeolite-containing adsorption layer provides an effective strategy for developing next-generation dialysis membranes with potential applicability in wearable artificial kidney systems.