Development of a novel genosensor based on ferrocenyl oligonucleotides.

Two types of ferrocenyl oligonucleotides, Fc1-ODN and Fc2-ODN, carrying a 5'-ATT GCT CAG GGG TAA GGT CAT TAG TTG GAA-3' sequence were allowed to hybridize with the DNA probe carrying a complementary sequence immobilized on the gold electrode to give rise to a redox signal deriving from their ferrocenyl moieties. When a mixture of these oligonucleotides in a proper ratio was used as a model of DNA samples, two redox peaks were observed in one differential pulse voltammogram. The peak currents varied depending on the initial ratio of the two oligonucleotides, suggesting a possibility that this technique may be applied to electrochemical monitoring of gene expression by, for example, the electrochemical differential hybridization, EDH.