DNA charge transport over 34 nm
Molecular wires show promise in nanoscale electronics but the synthesis of uniform, long conductive molecules is a significant challenge. DNA of precise length, by contrast, is easily synthesized, but its conductivity has not been explored over the distances required for nanoscale devices. Here we demonstrate DNA charge transport (CT) over 34 nm in 100-mer monolayers on gold. Multiplexed gold electrodes modified with 100-mer DNA yield sizable electrochemical signals from a distal, covalent Nile Blue redox probe. Significant signal attenuation upon incorporation of a single base pair mismatch demonstrates that CT is DNA-mediated. Efficient cleavage of these 100-mers by a restriction enzyme indicates that the DNA adopts a native conformation that is accessible to protein binding. Similar electron transfer rates are measured through 100-mer and 17-mer monolayers, consistent with rate-limiting electron tunneling through the saturated carbon linker. This DNA-mediated CT distance of 34 nm surpasses most reports of molecular wires.
© 2011 Macmillan Publishers Limited. Received 8 October 2010; accepted 17 December 2010; published online 30 January 2011. This research was supported by the National Institutes of Health (GM61077). J.D.S. also thanks the National Institute of Biomedical Imaging and Bioengineering for a postdoctoral fellowship (F32EB007900). The authors thank J. Genereux, A. Gorodetsky and M. Buzzeo for discussions, and K. Kan for assistance with the fabrication of the silicon chips. This work was completed in part in the Caltech Micro Nano Fabrication Laboratory. Contributions: J.K.B., J.D.S. and N.B.M. conceived and designed the experiments. J.D.S., N.B.M. and S.E.R. carried out the experiments. J.D.S., N.B.M. and J.K.B. analysed the results and co-wrote the paper. The authors declare no competing financial interests.
Accepted Version - nihms277095.pdf
Supplemental Material - nchem.982-s1.pdf