Supermolecular Interaction of Ferrocenium with Yeast DNA and Application in Electrochemical Sensing for Hybridization Recognition of Yeast DNA

The supermolecular interactions of single-stranded yeast DNA (ssDNA) and double-stranded DNA (dsDNA) with ferrocenium (Fc+) both in solution and at the electrode/solution interface were studied with UV spectroscopy and electrochemical method. The interaction of covalently immobilized dsDNA with Fc+ resulted in a change of the electrode behavior from diffusion-controlled to surface-controlled and an increase in the current response of Fc+ reduction, which has been used to develop a novel electrochemical yeast DNA sensor for hybridization recognition of immobilized yeast ssDNA to its complementary ssDNA (cDNA). The adsorption constants of Fc+ on ssDNA and dsDNA modified gold electrode surface were (3.38±0.04)×103 M-1 and (2.02±0.02)×104 M-1, respectively, indicating a higher affinity of dsDNA to Fc+. UV spectra and the influence of ion strength showed that the interaction mode between Fc+ and dsDNA in solution might be a groove binding. The interaction between Fc+ and immobilized DNA was mainly an electrostatic model.