Chemical grafting of sulfobetaine onto poly(ether urethane) surface for improving blood compatibility

Poly(ether urethane)s (PEUs) are widely used as blood-contact biomaterials because of their good biocompatibility and mechanical properties. Nevertheless, their blood compatibility is still not adequate for more demanding applications. Surface modification is an effective way to improve blood compatibility and retain bulk properties of biomaterials. The purpose of the present study was to design and synthesis a novel non-thrombogenic biomaterial by modifying the surface of PEU with zwitterionic monomer. In this study, sulfobetaine was grafted onto PEU surface through the following reaction steps: (1) Poly(propylene oxide) (PPO) was reacted at both chain ends with hexamethylene diisocyanate (HDI), and OCN–PPO–NCO was obtained; (2) OCN–PPO–NCO was reacted at one chain end with N,N-dimethylethanolamine (DMEA) and OCN–PPO–N(CH3)2 was formed; (3) the sulfobetaine was prepared by a ring-opening reaction between OCN–PPO–N(CH3)2 and 1,3-propanesultone (PSu); (4) the sulfobetaine was grafted onto PEU surface by the reaction between NCO and the N–H bonds of PEU. The surface composition of films and the hydrophilicity on the PEU surface were investigated by X-ray photoelectron spectroscopy analysis and contact angle measurements, respectively. The blood compatibility of PEU was evaluated by platelet-rich plasma contact experiments and the results were observed by scanning electron microscopy. The state of platelet adhesion and shape variation for the attached platelets was described. The modified surface showed excellent blood compatibility, featured by low platelet adhesion. Copyright © 2003 Society of Chemical Industry