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    Switched-on DNA: Sparking Nano-Electronic Applications

    February 21, 2017, Categories  Physics, Technology/Electronics, Biology/Biotechnology

    EC gate control of DNA conductance. (a) Illustration of the experiment, where the source and drain electrodes are the STM tip and substrate, and EC gate is a silver electrode inserted in the solution. A DNA molecule bridged between the source and drain electrodes via the thiolate linker groups, where charge hops from one base to the next (red arrows) via overlapping π-orbitals. The source-drain bias (Vds), and the EC gate voltage (Vg) are controlled independently. (b) From left to right: redox modified DNA (Aq-DNA), where a base was replaced with an anthraquinone (Aq) moiety (highlighted in blue) at the 3′-end of a DNA strand (see chemical structure in Supplementary Fig. 1a); three-dimensional structure (PDB ID: 2KK5, results are from nuclear magnetic resonance study17) shows that the Aq moiety intercalated in between the two Guanine bases on the other strand acts as a hopping site (red arrows) with its π-orbital overlapping with those from adjacent bases. Aq moiety is shown in blue. Picture is created from 2KK5 in PDB with JSmol software. DNA without the Aq moiety (u-DNA) was studied as control. Both Aq-DNA and u-DNA contain a strand terminated with thiolated linkers at the 3′- and 5′-ends for contact with the source and drain electrodes.

    EC gate control of DNA conductance.

    DNA may very well also pack quite the jolt for engineers trying to advance the development of tiny, low-cost electronic devices. Much like flipping your light switch at home – only on a scale 1,000 times smaller than a human hair – an ASU-led team has developed the first controllable DNA switch to regulate the flow of electricity within a single, atomic-sized molecule.

    “It has been established that charge transport is possible in DNA, but for a useful device, one wants to be able to turn the charge transport on and off. We achieved this goal by chemically modifying DNA,” said Tao, who directs the Biodesign Center for Bioelectronics and Biosensors and is a professor in the Fulton Schools of Engineering...

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