Gate-controlled conductance switching in DNA

Abstract

Extensive evidence has shown that long-range charge transport can occur along double helical DNA, but active control (switching) of single-DNA conductance with an external field has not yet been demonstrated. Here we demonstrate conductance switching in DNA by replacing a DNA base with a redox group. By applying an electrochemical (EC) gate voltage to the molecule, we switch the redox group between the oxidized and reduced states, leading to reversible switching of the DNA conductance between two discrete levels. We further show that monitoring the individual conductance switching allows the study of redox reaction kinetics and thermodynamics at single molecular level using DNA as a probe. Our theoretical calculations suggest that the switch is due to the change in the energy level alignment of the redox states relative to the Fermi level of the electrodes.

Abstract

Thanks to its base stacking structure, DNA can behave as an electric wire, but external control of its electronic properties has not been achieved yet. Here, the authors show that DNA conductance can be switched electrochemically when a DNA base is replaced by the redox molecule anthraquinone.