Electrodeposition of polypyrrole-heparin and polypyrrole-hydroxyapatite films

Composite films containing heparin and hydroxyapatite in a polypyrrole (PPY) matrix were electrochemically deposited as monolayers or bi-layers on conductive substrates. The deposition on stainless steel substrates was achieved using a thin prime layer of PPY deposited by anodic electropolymerization in the presence of salicylate anions, which passivated the substrate surface. The deposition mechanism, film composition and morphology were investigated. The films containing heparin may have improved anticoagulant activity as suggested by their ability to bind antithrombin from plasma.