In-vivo tissue response to polyaniline

Polyaniline (PANi) powders and films of the emeraldine (EM), nigraniline (NA) and leucoemeraldine (LM) states, as well as surface-modified EM base films from graft copolymerization with acrylic acid (AAc) and the subsequent covalent immobilization of collagen were implanted into male Sprague Dawley rats beneath the dorsal skin, for a period ranging from 19 to 50 weeks to evaluate the in vivo tissue response. It was observed that inflammation associated with the various forms of PANi was minimal after 50 weeks. Histological examinations of tissues, 24 weeks after the implantation, revealed that the pristine EM film was encapsulated by several loosely arranged fibrous tissue. The collagen-immobilized EM film, on the other hand, showed no features resulting from tissue incompatibility near the implant.