Polyaniline nanowires were electrodynamically deposited onto the glass carbon electrode (GCE) and the diameters of the tips range from 80 to 100 nm examined by a field emission scanning electron microscope (SEM). Oligonucleotides with phosphate groups at the 5' end were covalently linked onto amido groups of polyaniline nanowires in the presence of the water-soluble coupling reagent l-ethyl-3-(3-dimethyl- aminopropy-l)-carbodiimide (EDC). The hybridization events were monitored with differential pulse voltammetry (DPV) measurement using methylene blue (MB) as the indicator and the decreases in the peak currents of MB were observed. The approach described here can effectively discriminate complementary from noncomplementary DNA sequence.

Key words: polyaniline nanowire, DNA hybridization, electrochemical detection