Electrochemical detection of single-base mismatches in DNA by a redox-active intercalator conjugated oligonucleotide.

A simple and direct electrochemical detection of DNA single-base mismatches utilizing anthraquinone-modified oligonucleotides (AQ-ODNs) bound to gold electrodes has been described. By using the redox-active oligonucleotides, the redox-active center can be positioned at the desired base-pair pocket in double-helical DNA, enabling us to measure the charge transport between the redox-active center and the electrode that sandwich mismatched and full-matched base-pairs in double helix. AQ-ODNs immobilized on gold electrodes have been found to be useful in the electrochemical discrimination of hybrids containing a single-base mismatch from the one with fully matched bases.

Probing DNA sequences by anthraquinone-modified DNA that is immobilized on gold surface.

2'-Anthraquinone-modified oligonucleotide (AQ-ODN) possessing disulfide terminus has been immobilized on the gold electrode surface. The AQ-ODN-modified electrode showed faster electron transferability in double-stranded form than that in single-stranded form.