hexylamine)] poly(Py-<i>co</i>-PyHA), to enhance the electrostatic interaction between DNAs and polymer and increase the sensitivity of biosensors. Afterwards, probe DNA was immobilized onto the surface of polypyrrole (PPy) and its copolymer film in PBS which is ascribe to electrostatic adsorption between negative charges of DNA chain and positive charges of copolymer. There is no non-specific adsorption between the target DNA and polymer surface. And the total match target DNA can hybridize with probe DNA onto the polymer. This result will be important to study conducting polymer as potential DNA biosensors in the future.

Key words: conducting pyrrole, electrochemical cyclic voltammetry, label-free DNA immobilization, DNA hybridization