DNA sensor based on functionalized polypyrrole

A novel DNA sensor based on a functionalized polypyrrole was prepared. The sensor film was obtained by electrocopolymerizing poly(pyrrole-co-4-(3-pyrrolyl) butanoic acid) onto which an NH2-ODN probe was grafted. The obtained sensor is a simple, label-free DNA sensor with direct electrical read-out. Hybridisation with complementary ODN was investigated by observing changes in the cyclic voltammogram and the AC impedance spectrum. Significant modifications of both the voltammogram and AC impedance spectrum were observed when the sensor was incubated in the presence of complementary ODN. The AC impedance spectra show an increased charge transfer resistance of the film after hybridisation.