Covalent coating strategy for enhancing the biocompatibility and hemocompatibility of blood-contacting medical materials

Blood-contacting medical devices/materials are widely used in the diagnosis and treatment of a variety of diseases. Functional coatings of medical devices are considered one of the core functions in the future, overcoming the limitations of medical devices/materials without modification, including plasma proteins adhesion, platelet activation and coagulation cascade normally result in clotting and thrombosis in clinical use, posing a serious threat to the health and life of patients. In order to improve the anticoagulant properties of material/device surfaces, several surface modified techniques have been developed. Among them, covalent graft method has attracted much attention due to its high stability and excellent hemocompatibility. This review encompasses various covalent modification methods on the surface of blood-contacting medical materials, such as chemical polymers, metallic biomaterials, nylon net membrane, glass slide and etc. Firstly, an overview of the covalent immobilization method for coating is summarized. Secondly, surface coating methods including physical adsorption, electrostatic attachment and layer-by-layer deposition are presented. Finally, the advantages and disadvantages of covalent immobilization method and other methods are compared. Collectively, the information complied should serve as a comprehensively repository in covalent coating strategy for blood-contacting surface, expecting to provide a general retrospect and prospect on the research progress of anticoagulant surface construction and its application in medical devices.