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)×10 M and (2.02±0.02)×10 M, 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.