Sodium alginate/heparin composites on PVC surfaces inhibit the thrombosis and platelet adhesion: applications in cardiac surgery.

Thrombosis and hemocyte damage are the main problems of applied non-coated biomaterials to cardiac surgery that remain unsolved. The present study is aimed at the chemical modification of polyvinyl chloride (PVC) for applications in cardiac surgery and the biological property assessment of modified PVC. Sodium alginate (SA)/heparin (HEP) composites were covalently immobilized onto the surface of the PVC pipeline. The surface grafting density and protein adsorption were determined by ultraviolet spectrophotometry. The surface contact angles were evaluated by contact-angle measurement, whereas the surface characteristics were evaluated by Fouriertransform infrared spectroscopy. Blood coagulation time and platelet adhesion were measured using an automated blood coagulation analyzer and a hemocytometer, respectively. Surface morphologies of the thrombus and platelets were evaluated by scanning electron microscopy. The immobilization of SA/HEP reduced the contact angles of the coated surface. Protein adsorption was reduced by the immobilization of SA. The activated partial thrombin time and thrombin time of the coated PVC were significantly prolonged as compared with the non-coated PVC. Platelet adhesion and thrombus formation were all reduced by the immobilization of HEP. The results revealed that the SA/HEP coating can improve the antithrombogenicity of the PVC pipeline, as well as improve its biocompatibility and hemocompatibility, which are essential for cardiac pulmonary bypass surgery.