Improvement hemocompatibility of antithrombotic PMP hollow fiber membranes based on the modification of zwitterionic polymer in ECMO application

Extracorporeal membrane oxygenation (ECMO) system is a life-supporting technique that plays an important role in cardiopulmonary failure or heart transplantation. Blood passes through the oxygenator to expel carbon dioxide (CO₂) produced during the metabolic processes while supplementing the blood with oxygen (O₂) to maintain the patient's life. As the key part of the oxygenator, the membranes come into direct contact with the blood for gases exchange. Therefore, membranes should possess excellent hemocompatibility to inhibit thrombosis and hemolysis. In this work, an antithrombotic coating was constructed on the surface of poly-4-methyl-1-pentene (PMP) hollow fiber membranes based on the co-deposition of zwitterionic polymer and dopamine to reduce the protein adsorption and improve hemocompatibility of the pristine PMP membranes. The experimental results were confirmed that the protein adsorption and the clotting time of the modification coating on the surface of PMP hollow fiber membranes were 16.3 μg/cm² and 643 s, which were 70.58 % lower and 36.8 % higher than that of the commercial PMP hollow fiber membranes (55.4 μg/cm² and 470 s), respectively. Test devices of in vitro blood circulation and in vivo circulation in animals were established to evaluate blood compatibility and the blood-gas exchange performance of as-prepared membrane modules, respectively, the evaluation conditions of which are similar to those of the real ECMO system. Meanwhile, the corresponding results exhibited that the poly (sulfobetaine methacrylate) (PSBMA) modified coating had good oxygenation performance and biosafety, implying that the zwitterionic polymer could provide excellent hemocompatibility for gas-blood exchange membranes in ECMO systems.