Surface modification and blood compatibility of polyacrylonitrile membrane with immobilized chitosan-heparin conjugate

Polyacrylonitrile (PAN) membranes were hydrolyzed with sodium hydroxide to introduce carboxyl groups, and then grafted with chitooligosaccharides (COS), followed by the immobilization of heparin (HEP). The properties of heparin and chitosan-immobilized PAN membranes were characterized with infrared spectroscopy. The surface densities of carboxyl groups, COS, and HEP on the PAN membranes were determined by the uptake of dye. Blood compatibility was evaluated by the activated partial thromboplastin time (APTT). The protein affinity was determined by human plasma total protein. The results showed that the amount of immobilization of COS and HEP increased with the density of carboxyl groups. The heparinized PAN membrane showed longer APTT and decreasing adsorption of plasma proteins. Less than 10% of heparin was released within 24 h, thus demonstrating the stability of the heparinization. These results demonstrated that the blood compatibility of PAN membranes could be improved by the immobilization of chitosan-heparin conjugate. The results obtained in this study will be helpful for the development of modified PAN for clinical applications.