Study of charge transport mechanisms in single dsDNA molecules
Understanding charge transport in DNA molecules is a long-standing problem of fundamental importance across disciplines. It also has a great technological interest due to DNA’s ability to form versatile and complex programmable structures. Experiments so far have yielded seemingly contradictory results that range from insulating or semiconducting to metallic-like behavior. Here we report charge transport measurements through single 30 nm long double-stranded DNA (dsDNA) molecules with an experimental setup that enables us to address individual molecules repeatedly and perform source-drain-gate measurements at a wide range of temperatures. We observe surprisingly high currents and unusual temperature dependence, which contradicts the most commonly accepted transport mechanisms for DNA but might be consistent with charge transport in organic crystals. Moreover, we show that the presence of even a single discontinuity (“nick”) in both strands composing the dsDNA leads to complete suppression of the current, suggesting that the backbones mediate the long-distance conduction in dsDNA, contrary to the common wisdom in DNA electronics.
Seminar will be held via Zoom: https://umd.zoom.us/j/95710381964 and Meeting ID: 957 1038 1964