Improving blood-compatibility via surface heparin-immobilization based on a liquid crystalline matrix

Blood compatibility is of considerable importance in developing medical materials and devices that are in contact with blood. In this work, we successfully developed a novel liquid crystalline heparin-immobilized material (Hep-OPPC) by two-step modification for further improvement of hydrophilicity and hemocompatibility of the liquid crystalline hydroxypropyl cellulose ester (OPCL). The results showed that Hep-immobilization on the OPCL led to dramatic changes in the surface morphology and crystallinity, whereas, the Hep-OPPCs also maintained the liquid crystalline feature at room temperature after heparinization. Furthermore, the hemocompatibility of the Hep-OPPCs was markedly enhanced at low levels of hemolysis assay (HR) with unimpaired erythrocytomorphology, significantly lower concentrations of C3a in blood plasma and remarkable increases in plasma re-calcification time (PRT). This suggests that the heparinized surface could restrict the transformation of fibrinogen with less activation of the intrinsic coagulation system. Moreover, the activated partial thromboplastin time (APTT) and prothrombin time (PT) values of the Hep-OPPCs with low heparin density could also be prolonged in this study suggesting that the liquid crystal feature of the matrix might be blocking the clotting factors. We concluded that the heparin-immobilized liquid crystalline material has the potential to be used in blood-contact materials.