High performance thin-film nanofibrous composite hemodialysis membranes with efficient middle-molecule uremic toxin removal

Abstract

Membrane structure design is critical for the development of high-performance hemodialysis membranes. Here, a thin-film nanofibrous composite (TFNC) membrane, consisting of a two-tier composite structure, i.e., an ultrathin hydrophilic separation layer of chemically cross-linked polyvinyl alcohol (PVA), and an electrospun polyacrylonitrile (PAN) nanofibrous supporting layer, was demonstrated as the hemodialysis membrane for the first time. The optimized PVA/PAN TFNC membrane exhibited high permeability (~ 290.5 L/m 2 h at 0.1 MPa) and excellent selectivity which should be attributed to its unique structure with ultrathin separation layer and highly porous supporting layer. In addition, the TFNC membrane also possessed excellent overall mechanical properties, good hydrophilicity and comparable hemocompatibility properties (protein adsorption, platelet adhesion, complement activation, hemolysis ratio). The hemodialysis simulation experiments on optimized TFNC membrane showed that 82.6% of urea and 45.8% of lysozyme were cleaned and 98.8% of bovine serum albumin (BSA) was retained. The TFNC membranes exhibited excellent hemodialysis performances, especially for the middle-molecule uremic toxin removal, which was more efficient than conventional hemodialysis membranes reported so far, suggesting PVA/PAN TFNC membranes as promising alternatives for hemodialysis applications.

Polydopamine/cysteine surface modified hemocompatible poly(vinylidene fluoride) hollow fiber membranes for hemodialysis

“…The dialysis test cell has an effective volume of about 100 mL containing a membrane module of 10–20 fiber membranes with two separate compartments, and their own inlet and outlet. 500 mL simulation solution containing urea (1.5 g/L), lysozyme (0.2 g/L) and BSA (1.0 g/L) were prepared, and distilled water as dialysate solution . The flow rates of dialysate solution and simulation solution were kept at 200 mL/min and 100 mL/min (37°C) .…”

Iron oxide nanoparticles improved biocompatibility and removal of middle molecule uremic toxin of polysulfone hollow fiber membranes

“…The results of fibrinogen, HSA, HGG, and BSA adsorption are presented in Figure (a), where the graph of protein adsorption against the Fe 2 O 3 NPs loading shows a decreasing trend. Habitually, hydrophilic membranes have a lesser tendency to adsorb proteins, proven by the decreased amount of adsorbed protein per unit area of the membranes . The amount of fibrinogen adsorbed was the highest due to the greater net negative charge of fibrinogen as compared to other proteins .…”

“…The membrane module was equipped with an inlet and an outlet connected to two separate compartments: feed and dialysate. The feed tank was filled with a mixture of solutes containing urea (1500 ppm) and lysozyme (40 ppm) in RO water to mimic the real condition of hemodialysis treatment while the dialysate tank was filled with RO water . Urea was used as the most abundant uremic toxin and lysozyme was used in place of middle molecular β 2 ‐microglobulin.…”

“…The major problem associated with current hemodialysis treatment is the membrane incapability to remove middle molecule uremic toxins (>500 Da) . Middle molecular weight toxin like β 2 ‐microglobulin may form large molecules which later deposit and harm nearby tissues, causing anxiety or amyloidosis to patients . Generally, uremic toxin removal by membrane is based on the concentration differences and convective separation .…”

“…Generally, uremic toxin removal by membrane is based on the concentration differences and convective separation . However, the removal of larger uremic toxins is difficult as the clearance by diffusion decreases with the increasing molecular weight of molecules . Altering the membrane pore size may end up causing trade‐off effect, whereby the membrane could not remove these middle molecule uremic toxins efficiently without losing essential proteins .…”