Electrocatalysis, at DNA-modified electrodes

Elizabeth M. Boon, Donato M. Ceres, Thomas G. Drummond, Michael G. Hill, Jacqueline K. Barton, Mutation detection by electrocatalysis at DNA-modified electrodes. Nature Biotechnology, 18 (2000), 1096-1100. 

The chemical reduction of Fe(CN)g was identified as a reaction that would be catalyzed by electrochemically reduced MB intercalated within a DNA film. This electrocatalytic process is thermodynamically favored by 0.6 eV. Indeed, in the absence of MB, no signal is obtained for the anionic probe at a DNA-modified electrode, presumably because of electrostatic repulsion. In addition, the association of MB with the DNA film produces currents corresponding to the reduction of 1.4 molecules per immobilized duplex (Figure 8). However, when both MB and Fe(CN)g " are present in solution, irreversible electrochanical signals corresponding to multiple turnovers of the intercalated catalyst are observed. Only low levels of electrocatalysis were obtained when daunomycin was used as the intercalated species this probe binds DNA with higher affinity and may have slower exchange dynamics or solvent accessibility. 

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