The Research Of Ultraviolet Graft Anticoagulation Modified Hemodialysis Membrane

Background and objective:Hemodialysis is widely applied in clinic as one of the renal replacement treatment options. However, when the hemodialysis materials contact with blood, significant responses such as activation of the coagulation system or thrombus formation will occur, which is induced by the materials blood compatibility. Therefore, in order to avoid clot formation, the infusion of anticoagulant is required clinically during this process. Unfortunately, it brings another intractable problem, e.g. the systematical usage of anticoagulant will increase the bleeding danger for some high risk of bleeding patients.Through the further research of the coagulation mechanism between blood and surface. Many researchers suggest that plasma was immediately adhered on the membrane while blood encounters a foreign surface, but the coagulation system and platelet were activated after the plasma adhesion. Therefore, the well known concept such as reducing the thrombin generation and adherence ratio of platelet by modifying the membrane surfaces has been proposed for solving the problem. Accordingly, various approaches have been presented to modify the membrane surface for the expectance of improving the blood compatibility and achieving the goal of local anticoagulation in vitro. We expect to construct a novel membrane in order to minimize or avoid the use of anticoagulation and be suitable for the high-risk of bleeding patients. In order to construct a new type of hemodialysis membrane which can provide extraordinary biocompatibility and more efficient function of anticoagulant, we plan to graft argtroban onto the membrane surface by ultraviolet-induced techniquesMethods:(1) Using the polysulfone plane membrane as grafted matrix, benzophenone as photo-initiator and argtroban as graft monomer, we achieved the modified membrane by the surface UV-graft method;(2) To confirm the process of the UV-graft method, we use X-ray spectroscopy(XPS) and calculate the graft rate. we weighed the membrane’s weight before and after grafted, which are denoted as W0and W1respectively. Then the graft-ratio (G%) is calculated according to the formula which is G%=(W1-W0)/W0*100%;(3) We detect the change of surface morphologic characteraristics and thickness of the membrane based on scanning electron microscopy (SEM), atomic force microscope and drop shape analyzer;(4) Recalcification time、Hemolysis test、platelet adhesion study and plasma protein test were employed to evaluate the blood compatibility of argatroban modified membrane;(5) The dynamic coagulation time、the activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) were conducted to detect the anticoagulation performance of the modified membrane.Results:(1)Under the condition of thirty-seven degrees centigrade and one hour’s irradiation time, the grafted-ratio was10.74%, which proved that there are something on the membrane. The modification process was successfully confirmed by detecting XPS showed that one kinds of particular newly chemical elements N was detected on the surface of the modified membrane. The results of SEM and atomic force microscope showed that morphology characteristics and appearance of modified surface had no significant change.(2)The recalcification time、Hemolysis test showed that hemolysis rate of samples were lower than5%. Platelet adhesion study and plasma adhesion test showed that the number of platelets and plasma adhering to the modified membrane were much fewer than the other group, and of which the platelet activation extent were also lower.(3)The dynamic coagulation time, PT, APTT and TT test of modified membrane proved that argtroban modified membrane have better anticoagulation characteristics.Conclusion:(1) UV-graft method could be used for the Dialysis membrane surface modification, and argtroban could be successfully inarched onto the surface.(2) Modification of the membrane didn’t destruct the exterior structure and the permeability of membrane material.(3) Modified membrane provided a better blood compatibility.(4) Modified membrane suggested the stable anticoagulation characteristics.