Electrochemical Detection of a Dengue-related Oligonucleotide Sequence Using Ferrocenium as a Hybridization Indicator

A simple method for electrochemical detection of a synthetic 20-bp oligonucleotide sequence related with dengue virus genome was developed. A complimentary DNA probe sequence was electrostatically immobilized onto a glassy carbon electrode modified with chitosan. Electrochemical detection of hybridization between probe and target was performed by cyclic voltammetry, using ferrocene (Fc(+)) as a hybridization label. After hybridization, the peak current response of Fc(+) oxidation increased around 26%. A higher voltammetric decay rate constant (k(d)) and a lower half-life period (t(1/2)) for the interaction of Fc(+) with dsDNA compared to those with ssDNA quantitatively characterize the different strengths of interaction with both types of DNA. By combining the simplicity of DNA immobilization onto a chitosan film and suitable voltammetric detection of hybridization concomitant with ferrocene attachment, a good discrimination between ssDNA and dsDNA was obtained.