[Biospecific properties of lysine-contained polyelectrolyte coatings for devices contacting blood]

Biospecific properties of thromboresistant bilayer and multilayer coatings based on polyelectrolyte complexes of modified copolymer of N-vinylpyrrolidone and maleic acid (VPMA) with chitosan, amphiphilic chitosan or albumin were investigated. VPMA contained affinity ligand towards plasminogen--alpha-amino coupled lysine residues. Polyethylene and polystyrene surfaces were investigated before and after their covering by protective polyelectrolyte coatings. The specific adsorption of plasminogen (precursor of the fibrinolytic enzyme plasmin) from its solutions and from human plasma was investigated using these model systems. It was found that all coatings with the outer contact lay of lysine-contained affinity polymer had affinity to plasminogen. But multilayer polyelectrolyte coatings were more efficient than bilayer coatings with single application of layers and the affinity polymer coatings without interlayer. The decrease in trombogenicity degree of the materials modified by polyelectrolyte coatings was shown in vitro and ex vivo. Emplyment of proposed modification of surfaces will improve hemocompatibility of medical devices.