Blood compatibility of polyethersulfone membrane by blending a sulfated derivative of chitosan.

In this study, a novel sulfated derivative of chitosan, which could be dissolved in many common organic solvents, is conveniently synthesized for the modification of polyethersulfone (PES) membrane. Elemental analysis, FTIR, (1)H NMR and X-ray diffraction diagrams (XRD) are used to demonstrate the introduction of functional groups. Owing to the solubility in organic solvents, the sulfated derivative of chitosan could be directly blended with PES in organic solvent to prepare membrane by means of a liquid-liquid phase separation technique. The modified membrane showed lower protein (bovine serum albumin (BSA) and bovine serum fibrinogen (BFG)) adsorption and suppressed platelet adhesion. Moreover, the activated partial thromboplastin time (APTT) for the modified membrane was enhanced as high as 60% compared to pure PES membrane. The lower protein adsorption, suppressed platelet adhesion and increased APTT confirmed that the blood compatibility of the modified PES membrane by the sulfated derivative of chitosan was significantly improved.

Heparin-like surface modification of polyethersulfone membrane and its biocompatibility.

Sulfonated polyethersulfone (SPES) and poly (acrylonitrile-co-acrylic acid-co-vinyl pyrrolidone) (P(AN-AA-VP)), which provided sulfonic acid (-SO(3)H) and carboxylic acid groups (-COOH), respectively, were used to modify polyethersulfone (PES) membrane with a heparin-like surface by blending method. The SPES was prepared by sulfonation of PES using chlorosulfonic acid as the sulfonating agent, while the P(AA-AN-VP) was prepared through a free radical polymerization. The PES and modified PES membranes were prepared by a phase-inversion technique; the modified membranes showed lowered protein (bovine serum albumin, BSA; bovine serum fibrinogen, FBG) adsorption and suppressed platelet adhesion. For the modified membranes, significant decreases in thrombin-antithrombin (TAT) generation, percentage platelets positive for CD62p expression, and the complement activation on C3a and C5a levels were observed compared with those for the pure PES membrane. Due to the similar negatively charged groups as heparin, the modified membranes effectively prolonged the activated partial thromboplastin time (APTT). Furthermore, the modified membranes showed good cytocompatibility. Hepatocytes cultured on the modified materials exhibited improved functional profiles in terms of scanning electron microscope (SEM) observation and 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay compared with those on the pure PES membrane. It could be concluded that the modified membranes with sulfonic acid and carboxylic acid groups were endowed with excellent biocompatibility, and the heparin-like surface modification seemed to be a promising approach to improve the biocompatibility of materials.

Improved blood compatibility of polyethersulfone membrane with a hydrophilic and anionic surface.

In this study, a novel triblock copolymer of poly (styrene-co-acrylic acid)-b-poly (vinyl pyrrolidone)-b-poly(styrene-co-acrylic acid) (P(St-co-AA)-b-PVP-b-P(St-co-AA)) is synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization, and used for the modification of blood contacting surface of polyethersulfone (PES) membrane to improve blood compatibility. The synthesized block copolymer can be directly blended with PES to prepare PES membranes by a liquid-liquid phase separation technique. The compositions and structure of the PES membranes are characterized by thermogravimetric analysis (TGA), ATR-FTIR, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM); the surface charge density of the modified PES membrane was measured by Zeta-potential; the blood compatibility of the PES membranes was assessed by detecting bovine serum albumin (BSA) and bovine serum fibrinogen (BFG) adsorption, platelet adhesion, activated partial thromboplastin time (APTT), platelet activation, and thrombin-antithrombin III (TAT) generation. The results indicated that the blood compatibility of the modified PES membrane was improved due to the membrane surface modification by blending the amphiphilic block copolymer and the surface segregation of the block copolymer.

Surface modification of polyethersulfone membranes by blending triblock copolymers of methoxyl poly(ethylene glycol)-polyurethane-methoxyl poly(ethylene glycol).

The surface of polyethersulfone (PES) membrane was modified by blending triblock copolymers of methoxyl poly(ethylene glycol)-polyurethane-methoxyl poly(ethylene glycol) (mPEG-PU-mPEG), which were synthesized through solution polymerization with mPEG Mns of 500 and 2000, respectively. The PES and PES/mPEG-PU-mPEG blended membranes were prepared through spin coating coupled with liquid-liquid phase separation. FTIR and (1)H NMR analysis confirmed that the triblock copolymers were successfully synthesized. The functional groups and morphologies of the membranes were studied by ATR-FTIR and SEM, respectively. It was found that the triblock copolymers were blended into PES membranes successfully, and the morphologies of the blended membranes were somewhat different from PES membrane. The water contact angles and platelet adhesion were decreased after blending mPEG-PU-mPEG into PES membranes. Meanwhile, the activated partial thromboplastin time (APTT) for the blended membranes increased. The anti-protein-fouling property and permeation property of the blended membranes improved obviously. SEM observation and 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay proved the surfaces of the blended membranes promoted human hepatocytes adhesion and proliferation better than PES membrane.