Electrochemical detection of telomeric quadruplex DNA using ferrocenyl naphthalene diimide

Ferrocenylnaphthalene diimide (FND) could strongly bind to the synthetic telomere DNA, 5'-CAT GGT GGT TTG GGT TAG GGT TAG GGT TAG GGT TAC CAC-3', at 0.1 M KCl. The binding affinity of FND for the telomere DNA was ten times higher than that for calf thymus DNA under the conditions employed. Circular dichroism spectra suggested that the telomere DNA can form a tetraplex structure and FND can bind to it. Oligonucleotide extended by telomerase on the electrode could also be detected electrochemically by using FND, thereby suggesting the possibility that telomerase activity may be detected electrochemically.