Preparation of biofiltration membranes by coating electrospun polyacrylonitrile fiber membranes with layer-by-layer supermolecular polyelectrolyte films.

Electrospun polyacrylonitrile fiber membranes (EPFMs) were coated with multilayer films, assembled using the layer-by-layer (LbL) technique through the alternate deposition of poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA), to develop an antithrombogenic drug release membrane for hemodialysis. Methylene blue (MB) and heparin (HEP) were attached to the PAH and PAA multilayers, respectively, as model drug and antithrombogenic agent to investigate the dual functionality of the membranes. The positively (PAH, MB) and negatively (PAA, HEP) charged groups generated a supermolecular polyelectrolyte multilayer film (SPF) capable of loading high amounts of MB and HEP on the EPFMs at appropriate composition. The pH was fixed at 5.5 during assembly to stabilize the SPF. Heavy assembly of the PAH/PAA multilayer occurred at 10 wt% of both MB and HEP with 25 cycles of LbL deposition, and it exhibited long-term release of MB and low release of HEP at pH 7.4 in a circulatory system. The SPF-coated EPFMs also achieved low platelet attachment after 4 h of platelet rich plasma circulation and showed prolonged clotting times including thromboplastin, thrombin, and prothrombin times. Collectively, these observations suggest that SPF-coated EPFMs have great potential for use as hemodialysis membranes with positively charged drug loading.