High Electronic Conductance through Double-Helix DNA Molecules with Fullerene Anchoring Groups

Determining the mechanism of charge transport through native DNA remains a challenge as different factors such as measuring conditions, molecule conformations, and choice of technique can significantly affect the final results. In this contribution, we have used a new approach to measure current flowing through isolated double-stranded DNA molecules, using fullerene groups to anchor the DNA to a gold substrate. Measurements were performed at room temperature in an inert environment using a conductive AFM technique. It is shown that the π-stacked B-DNA structure is conserved on depositing the DNA. As a result, currents in the nanoampere range were obtained for voltages ranging between ±1 V. These experimental results are supported by a theoretical model that suggests that a multistep hopping mechanism between delocalized domains is responsible for the long-range current flow through this specific type of DNA. This project was funded by the Special Research Funds (BOF) of Hasselt University. The authors thank Dr. Patricia Losada-Perez and Dr. Alexander Volodin for fruitful discussions and Profs. Marlies K. Van Bael and Hans-Gerd Boyen for providing access to their experimental equipment.