AbstractThe polycation conducting polymers, oxidized polypyrrole and polyalkylthiophene, possess the ability to form complexes with polyanionic DNA molecules through largely electrostatic interactions. This study demonstrated the solution uptake and binding of 32p radiolabeled DNA by conducting polymer thick films (50–100μm). Polypyrrole (PPy) was synthesized by electrochemical methods and poly(3-hexylthiophene) (PHT) and poly(3-undecylthiophene) (PUT) were synthesized by chemical methods. The DNA binding rates on PPy films were affected by DNA concentration and the oxidation state (measured as conductivity). The DNA kinetics support a diffusion limited model for binding. We measured DNA binding levels onto all three polymer films; PUT, PHT, and PPy. The binding levels increased in the same order as the conductivities of the polymer films. DNA binding onto oxidized PPy film was diminished upon electrochemical reduction. These observations showed, therefore, the binding may be linked with the positive charge sites responsible for conduction in the polymer films.
