A novel natural hirudin facilitated anti-clotting polylactide membrane via hydrogen bonding interaction

Different from intensively used anticoagulant heparin, hirudin as a representative of natural bio-molecular inhibitors can form specific hirudin-thrombin complex and function as a serine proteinase to efficiently prevent blood coagulation with less bleeding adverse effect, no allergic reaction and immune of non-toxic reaction. We aim to develop a novel anticoagulant polylactide (PLA) membrane via immobilizing natural hirudin through the hydrogen bonding interaction. High amount of PVP (17.4 wt%) was first immobilized on the membrane surface through the interfacial crosslinking of P(VP-VTES). The abundant carbonyl groups with high inter-association constant (K=6000) on the membrane surface dominated the hydrogen bonding interaction with the carboxyl groups of hirudin [44]. The anti-clotting activity of PLA membrane increased with the active hirudin concentration. XPS, ATR-FTIR was conducted to confirm the chemistry evolution of PLA membranes immobilized by PVP and hirudin respectively. The intermediate PVP spacer promoted the hydrophilicity and effectively inhibited the platelet adhesion. While the enhanced hemocompatibility was distinctly revealed by the blood concretion four items (APTT, PT, TT and FIB) mainly thanks to the surface immobilization of hirudin. The anti-clotting stability of PLA membrane was evaluated with varied incubation time. The complement activation was also measured in terms of C3a and C5a. The anti-clotting PLA membrane showed excellent dialysis performances in terms of cleaning urea, creatinine, lysozyme while preserving BSA respectively.