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Direct current electrical characterization of ds-DNA in nanogap junctions

Authors
Type
Published Article
Journal
Applied Physics Letters
Publisher
American Institute of Physics
Publication Date
Apr 16, 2005
Volume
86
Issue
15
Identifiers
DOI: 10.1063/1.1900315
Source
LIBNA
License
Green

Abstract

Measurements of DNA conductivity, hybridization, and melting using electronic means can have wide applications in molecular electronics and biological sensors. We have fabricated nanogap break-junctions by electromigration through thin gold-on-titanium films. 18-mer thiolated ds-DNA molecules were covalently attached between the electrodes and dc electrical measurements were done. The conductance was measured through the molecule before and after a temperature ramp from 300 to 400 K. A dramatic decrease in conductance was observed, analogous to an electrical fuse, possibly attributed to complete or partial denaturing of the ds-DNA molecules bridging the nanogaps. We also show evidence that the dc resistance of dry DNA strands of the same length decreases with increasing guanine-cytosine content in the sequence with values ranging from 10 M Ω to 2 G Ω. These findings can have important consequences in DNA-based molecular electronics and direct label-free detection of DNA hybridization. The authors acknowledge the support of the NASA Institute for Nanoelectronics and Computing (INAC) at Purdue under Award No. NCC 2-1363 for funding the work.

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