Reaction of Cd(II)–Morin with dsDNA for biosensing of ssDNA oligomers with complementary, GCE-immobilized ssDNA

In this work, the complex cadmium(II)–morin was synthesized and its interaction with double-stranded salmon sperm DNA was studied by electrochemical methods on glassy carbon electrode (GCE). It was shown that Cd(II)–Morin with high electrochemical activity can intercalate into the double-helix DNA, and the binding stoichiometry and equilibrium dissociation constant according to the Hill model for cooperative binding were calculated to be 1.761 and 2.5 × 10− 5 M, respectively. Using Cd(II)–Morin as a novel hybridization indicator, the hybridization between the probe and its complementary and mismatched sequence was investigated by differential pulse voltammetry (DPV), which was to access the selectivity of the developed electrochemical DNA biosensor. The complementary target ssDNA could be quantified over the range from 2.69 × 10− 8 M to 9.16 × 10− 7 M with a linear correlation of 0.9971 and a detection limit of 9.30 × 10− 9 M. These results demonstrated that the Cd(II)–Morin indicator provides great promise for the rapid and selective measurement of the target DNA.