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(3) M(-1) and (2.02±0.02)×10(4) 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.