Novel heparin-mimicking polymer brush grafted carbon nanotube/PES composite membranes for safe and efficient blood purification

Abstract

Nowadays, polymeric membrane based hemodialysis is considered to be the most practical approach for the treatment of kidney failure. To develop advanced hemodialysis membrane integrated with favorable blood and cell compatibilities and efficient blood purification ability, novel biocompatible composite membranes consisting of heparin-mimicking polymer brush functionalized carbon nanotubes (f-CNTs) and polyethersulfone (PES) are designed. Firstly, surface initiated atom transfer polymerization (SI-ATRP) is applied to synthesize heparin-mimicking polymer brush (contained the sodium styrene sulfonate (SS) and methyl ether methacrylate (EGMA) units) grafted CNT. Then, the f-CNT/PES composite membranes are prepared by a liquid–liquid phase separation technique. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) results indicated that the f-CNT would not cause severe damage on the membrane morphologies. Systemic protein ultrafiltration experiment indicated that the heparin-mimicking composite membranes owned satisfied antifouling property and protein rejection ratio. Further blood compatibility evaluation revealed that the composite membranes had decreased protein adsorption, prolonged clotting time, and suppressed platelet adhesion compared to pristine PES membrane. The results of human embryonic hepatocytes (LO-2) culture revealed that the cyto-compatibility of the modified membrane was enhanced by the blending of heparin mimicking polymer functionalized CNT. Furthermore, with the addition of f-CNT, the composite membranes showed remarkably increased removal efficiency of uremic toxin. In general, the fabricated heparin-mimicking f-CNT/PES composite membranes exhibited anti-fouling ability in ultrafiltration, excellent blood and cell compatibility and efficient toxic molecules removal ratio, thus present great potential for various applications, such as hemodialysis and bio-artificial liver support. Furthermore, the proposed method might forward the fabrication of advanced hemodialysis membrane by integrating functional nanomaterials and bioactive polymers.