A hierarchical 3-tier architecture enables excellent biointerface for zwitterionic fluorinated imidazole-containing polyethersulfone ultrafiltration membranes

A hierarchical 3-tier architecture was constructed on the surface of zwitterionic M1 / M2 membranes. • M1 and M2 membranes showed excellent antifouling performance with FRR reaching 93.75 % and 95.93 %. • M1 and M2 membranes showed good anticoagulant activity with PRT reaching 28.9 and 32.1 min. • M1 and M2 membranes showed low immune response with C5a decreasing to 1.62 and 1.31 ng/mL. Although polyethersulfone (PES) ultrafiltration membranes possess good thermal stability, mechanical stability, and biocompatibility, their inherent hydrophobicity leads to severe organic fouling and flux decline. Herein, a synergistic modification strategy combining fluorination and zwitterionization is proposed to address this issue. A three-tier hierarchical structure was constructed on the surfaces of the M1 and M2 membranes, consisting of an outer zwitterion-induced highly hydrophilic hydration layer, an intermediate CF 3 -induced hydrophobic low-surface-energy lubricious layer, and an underlying imidazole N–H-induced hydrogen-bonded hydration layer. This unique surface design endows the membrane surface with a biointerface featuring high permeability, low fouling, and hemocompatibility. Compared with the pristine PES membrane (M0), the M1 and M2 membranes exhibit significantly enhanced pure water flux (271.6 and 292.0L m −2 h −1 , respectively, vs. 241.1 L m −2 h −1 for M0), substantially reduced bovine serum albumin adsorption (30.56 and 17.67μg cm −2 , respectively, vs. 171.98μg cm −2 for M0), as well as markedly suppressed erythrocyte and platelet adhesion, with antibacterial adhesion efficiency exceeding 90 % for both membranes. Hemocompatibility tests further demonstrate that the zwitterionic membranes achieve hemolysis ratios as low as 0.39 % and 0.34 %, respectively, along with favorable anticoagulant properties and the ability to inhibit complement activation. A hierarchical 3-tier architecture constructed by zwitterionic fluorinated PES provides a promising solution to create excellent biointerface for heavily used UF membranes. Download: Download high-res image (145KB) Download: Download full-size image