Biospecific properties of lysine-containing polyelectrolyte coatings for blood contacting devices

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 an affinity ligand towards plasminogen, α-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 layer of the lysine-containing affinity polymer exhibited affinity towards plasminogen. However, multilayer polyelectrolyte coatings were more efficient than the bilayer coatings with a single layer application and the affinity polymer coatings without interlayer. The decrease in the degree of thrombogenicity of the materials modified by polyelectrolyte coatings has been demonstrated in vitro and ex vivo. Employment of the proposed modification of surfaces will improve hemocompatibility of medical devices.