Conductivity of a single DNA duplex bridging a carbon nanotube gap
We describe a general method to integrate DNA strands between single-walled carbon nanotube electrodes and to measure their electrical properties. We modified DNA sequences with amines on either the 5' terminus or both the 3' and 5' termini and coupled these to the single-walled carbon nanotube electrodes through amide linkages, enabling the electrical properties of complementary and mismatched strands to be measured. Well-matched duplex DNA in the gap between the electrodes exhibits a resistance on the order of 1 MΩ. A single GT or CA mismatch in a DNA 15-mer increases the resistance of the duplex approx300-fold relative to a well-matched one. Certain DNA sequences oriented within this gap are substrates for Alu I, a blunt end restriction enzyme. This enzyme cuts the DNA and eliminates the conductive path, supporting the supposition that the DNA is in its native conformation when bridging the ends of the single-walled carbon nanotubes.
© 2008 Macmillan Publishers Limited. Received 22 October 2007; accepted 3 January 2008; published 10 February 2008. We acknowledge primary financial support from the Nanoscale Science and Engineering Initiative of the National Science Foundation (NSF) under NSF award number (CHE-0117752 and CHE-0641523) and by the New York State Office of Science, Technology, and Academic Research (NYSTAR) and the NSF NIRT Award (ECCS-0707748). C.N. acknowledges a NSF CAREER award (no. DMR-02-37860). J.K.B. thanks the National Institutes of Health (NIH) (JKB-GM61077) for their financial support of this work. Author Contributions: X.G. and A.G. performed the experiments and wrote the manuscript. J.H., J.K.B. and C.N. designed the research and wrote the manuscript.
Accepted Version - nihms97811.pdf