In order to exploit the applications ofpolypyrrole （PPy） derivatives in biosensors and bioelectronics, the different immobilization mechanisms of biomolecules onto differently functionalized conducting PPy films are investigated. Pyrrole and pyrrole derivatives with carboxyl and amino groups were copolymerized with ω-（N-pyrrolyl）-octylthiol self-assembled on Au surface by the method of the chemical polymerization to form a layer of the copolymer film, i.e., poly[pyrrole-co-（N-pyrrolyl）-caproic acid] （poly（Py-co-PyCA）） and poly[pyrrole-co-（N-pyrrolyl）-hexylamine] （poly（Py-co-PyHA））, in which the carboxyl groups in poly（Py-co-PyCA） were activated to the ester groups. Based on the structure characteristics, the immobilization/hybridization of DNA molecules on PPy, poly（Py-co-PyCA） and poly（Py-co-PyHA） were surveyed by cyclic voltammograms measurements. For differently functionalized copolymers, the immobilization mechanisms of DNA are various. Besides the electrochemical properties of the composite electrodes of PPy and its copolymers being detected before and after bovine serum albumin （BSA） adsorption, the kinetic process of protein binding was determined by surface plasmon resonance of spectroscopy. Since few BSA molecules could anchor onto the PPy and its copolymers surfaces, it suggests this kind of conducting polymers can be applied as the protein-resistant material.
