Electrochemical gene detection based on supramolecular complex formation by ferrocenyl-β-cyclodextrin and adamantylnaphthalene diimide bound to double stranded DNA

Adamantylnaphthalene diimide 1 was synthesized as a highly selective double stranded DNA (dsDNA) binding reagent. The binding studies with sonicated calf thymus DNA as a model of dsDNA revealed that 1 can bind to dsDNA by the threading mode, where the two adamantyl moieties are located in the major and minor grooves of dsDNA separately and the complex of 1 with DNA duplex was stabilized by capping of the adamantyl moieties of 1 bound to dsDNA by β-cyclodextrin. The adamantyl moieties of 1 could be incorporated also into the cavity of ferrocenyl-β-cyclodextrin (Fc-β-CD), resulting in the formation of a supramolecular complex. When this complex is formed on the DNA probe-immobilized electrode, electrochemical DNA detection was feasible: the electrode hybridized with target DNA gave rise to a current peak corresponding to the ferrocene oxidation upon treatment with 1 and Fc-β-CD.