Towards Enhanced Bioactivity: Calcium Ion-Doped Polypyrrole

Abstract

Based on the unique redox property of electrically conductive polymers, Ca2+ was incorporated into polypyrrole (PPy) film that previously doped with polyelectrolyte heparin. Then the apatite-forming ability of the Ca2+-doped PPy was examined by a biomimetic method using stimulated body fluid (SBF), which has ion concentration nearly equal to those of human blood plasma. It was found that the Ca2+-doped PPy successfully formed bonelike apatite deposition on its surface after soaking in SBF for only 3 days, whereas the similar apatite deposition was formed on Ca2+-free PPy after soaking in SBF for 7 days. These indicated that the entrapment of Ca2+ into PPy could accelerate the formation of apatite deposition and the Ca2+-doped PPy was possessed of enhanced bioactivity. It is expected that the Ca2+-doped PPy would be a useful bioactive coating material of metallic medical devices or tissue engineering scaffolds to promote the bone tissue regeneration.