Albumin and heparin multilayer coatings for blood-contacting medical devices

Abstract

Three types of covalently crosslinked assemblies consisting of multiple (1) molecular layers of human serum albumin (HSA); (2) alternating layers of HSA and unfractionated heparin; and (3) alternating layers of HSA and partly depolymerized heparin fixed with one end to HSA were prepared on various surfaces. Adsorption of fibrinogen, IgG, and antithrombin (ATIII) from human citrated plasma on coated surfaces was evaluated by ELISA. Fibrinogen adsorption on coated ELISA plates was lower than that on bare polystyrene. There was no IgG adsorption on the HSA coating alone, but considerably high IgG adsorption was detected on the heparin-containing surface. The adsorption of ATIII increased with increasing heparin on the surface. The effect of multilayer coatings on platelets was tested by incubation of modified vascular prostheses with citrated blood. The most favorable interaction with platelets was observed on the HSA assembly. The interaction of platelets with the surface bearing unfractionated heparin was higher than that of the surface covered with partly depolymerized heparin. The long-term durability of the HSA-heparin coating was proven by a 21-day implantation of coated polyurethane plates in goat heart.