Research On Polyaniline With The Nanostructure: Synthesis, Characterization And Biomedicine Application

The conducting polymers with the nanostructure are clearly advantageous over their conventional counterparts because of their huge surface area, small size and quantum effects. Conductive polymer nanomaterials have a promising application in the biomedical field on the basis of the fact that neural tissue is sensitive to the electric field and the electrical stimulation. This article reviews various methods for the synthesis of conducting polymers with nanostructure and their applications in biomedical field, such as hard-template, soft-template, template-free synthesis. The potential of the conducting polymers with the nanostructures, such as nanofiber and nanoparticles, as neural electrode and biological conduit coating materials are also summarized.This dissertation mainly consisted of two parts:synthesis and applications of polyaniline (PANi) with the nanostructures. This paper was comprised of four chapters:Chapter one: the synthetic methods, the mechanism and the biomedical applications of the conducting polymers with the nanostructures were reviewed.Chapter two: the polyaniline with the nanostructures were successfully synthesized by the interfacial polymerization method in which the polymerization is performed in an immiscible organic/aqueous biphasic system. This paper examined the morphology of polyaniline prepared by using the different ratio of monomers to the oxidant. We found that when the ratio was 4:1, it tended to form nanofibers; when the ratio was 2:1, it tended to form nanoparticles. Reaction temperature and stiring also influenced on the morphology of polyaniline. So we summarized the best reaction conditions of the polymerization,which suggested a good reference for the use of the conducting polyaniline with the nanostructures as coating materials.Chapter three: the obtained polyaniline with the nanostructures were successfully deposited on Pt electrode via the in-situ method. The polyaniline coatings were characterized by the scanning electron microscopy (SEM), atomic force microscope (AFM), transmission electron microscopy (TEM), the conductivity measurement and water contact angle measurement. These results showed that the PANi coatings with the nanostructures were uniform and their conductivities were high enough for the biomedical application. Electrical stimulation for one month, the PANi coatings remained firmly adherent on the surface of the micro-electrode and were well-distributed, suggesting the potential of the polyaniline with the nanostructures as the electrode coatings.Chapter four: the potential of the polyaniline nanofibers as neural conduits coating was studied. Polyaniline coatings were deposited on zein tubes by a simple immersion method. We examined the in vitro degradation of zein tubes before and after the coating treatment. The results showed that polyaniline coatings not only could increase the conductivity of zein tubes, but also control the degradation of zein tubes by adjusting the coating thickness. We characterized the coating after the degradation of zein tubes, which provided the support for the future cytotoxic experiments.