Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 W4-11 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan.
Department of Biophysics, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo, Kyoto, 606-8502, Japan.
Nat Commun. 2021 Oct 1;12(1):5762. doi: 10.1038/s41467-021-25943-3.
The electrical properties of DNA have been extensively investigated within the field of molecular electronics. Previous studies on this topic primarily focused on the transport phenomena in the static structure at thermodynamic equilibria. Consequently, the properties of higher-order structures of DNA and their structural changes associated with the design of single-molecule electronic devices have not been fully studied so far. This stems from the limitation that only extremely short DNA is available for electrical measurements, since the single-molecule conductance decreases sharply with the increase in the molecular length. Here, we report a DNA zipper configuration to form a single-molecule junction. The duplex is accommodated in a nanogap between metal electrodes in a configuration where the duplex is perpendicular to the nanogap axis. Electrical measurements reveal that the single-molecule junction of the 90-mer DNA zipper exhibits high conductance due to the delocalized π system. Moreover, we find an attractive self-restoring capability that the single-molecule junction can be repeatedly formed without full structural breakdown even after electrical failure. The DNA zipping strategy presented here provides a basis for novel designs of single-molecule junctions.
DNA 的电学性质在分子电子学领域得到了广泛的研究。过去在这个主题上的研究主要集中在热力学平衡时静态结构中的输运现象。因此，到目前为止，还没有充分研究 DNA 的更高阶结构及其与单分子电子器件设计相关的结构变化。这源于一个限制，即只有极短的 DNA 可用于电测量，因为随着分子长度的增加，单分子电导率急剧下降。在这里，我们报告了一种 DNA 拉链构型，用于形成单分子结。双链体被容纳在金属电极之间的纳米间隙中，其构型为双链体垂直于纳米间隙轴。电测量表明，由于离域的π体系，90 个碱基对 DNA 拉链的单分子结表现出高电导。此外，我们发现了一种吸引人的自修复能力，即即使在电故障后，单分子结也可以在不发生完全结构破坏的情况下反复形成。这里提出的 DNA 拉链策略为单分子结的新设计提供了基础。
