Phosphorylcholine/Heparin Composite Coatings on Artificial Lung Membrane for Enhanced Hemo-compatibility

Abstract

As the key component of extracorporeal membrane oxygenation (ECMO), artificial lung membranes have low gas permeability and plasma leakage problems, and the contact between membrane materials and blood can cause coagulation, leading to the blockage of medical equipment and seriously threatening the safety of human life. In our work, poly(4-methyl-1-pentene) hollow fiber membranes (PMP HFMs) were prepared by the thermally induced phase separation (TIPS) method, the redox method was adopted for the surface hydroxylation of PMP HFMs, and then, heparin (Hep) and 2-(methacryloyloxy)ethyl(2-(trimethylammonio)ethyl) phosphate (MPC) were grafted to the surface of PMP HFMs to prepare anticoagulant coatings. The gas permeability and hemo-compatibility of the coatings were investigated by various characterization methods, such as gas flow meter, scanning electron microscope, extracorporeal circulation experiment, etc. The results show that PMP HFMs possess a bicontinuous pore structure with a dense surface layer, which could maintain good gas permeability with an oxygen permeance of 0.8 mL/bar•cm 2 •min and stable gas selectivity. Furthermore, the whole blood circulation of rabbit indicated that a composite surface of bioactive Hep and biopassive MPC might be used as artificial lung membranes without the formation of thrombosis within 21 days.

Anticoagulation Strategies During ECMO Application

“…To prevent ECMO thrombosis without the use of systemic anticoagulant drugs, coating ECMO membranes with anticoagulant drugs is being considered. Hydrogel coating with bivalirudin, which is still in the experimental stage, does not affect coagulation levels and reduces the risk of complications such as systemic bleeding compared to intravenous injection [52]. Phosphorylcholine/heparin composite and polycarboxybetaine coatings are still in the experimental stage [53].…”

Immobilization of carbonic anhydrase on modified PES membranes for artificial lungs

“…Therefore, adverse effects such as plasma protein adsorption may occur quickly during ECMO treatment, which would affect the efficiency of the ECMO membrane, and even lead to platelet adhesion and further clotting. 6–8 Due to the limitations of the preparation methods of the traditional ECMO commercial materials, PMP and PP, many studies focus on preparing anticoagulant coatings with heparin, 9 albumin, 10 silicone 11 and cross-linked polyvinyl alcohol 12 on the surface to improve the blood compatibility. However, protein adsorption resulting from the nature of the hydrophobic matrix would still affect the efficiency of the membrane.…”