Anti-thrombogenicity by layer-by-layer: Self-assembled polyelectrolyte film

Anti-thrombogenic films with high durability were fabricated in a wet process. Anti-thrombogenicity was achieved with polyelectrolyte multilayer thin film prepared from poly(vinyl alcohol)-poly(acrylic acid)(PVA-PAA) blends, deposited in alternate layers with poly(allylamine hydrochloride) (PAH). Film durability, assessed by abrasion resistance and water resistance, was enhanced by forming crosslinks via amide bonds induced by heat treatment of the film. The film was found to be resistant to protein adsorption, as measured by the amount of fibrinogen adsorbed from an aqueous solution. Anti-thrombogenic efficacy was assessed in ex vivo experiments by the ability of stainless steel mesh, coated with the polyelectrolyte and inserted into a pig blood vessel, to inhibit thrombus formation. Mesh coated with the polyelectrolyte did not reduce blood flow over a period of 15 minutes, whereas with uncoated mesh blood flow stopped within 6 minutes because of blood vessel blockage by thrombus formation.