Single-molecule junction spontaneously restored by DNA zipper

Abstract

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.

Characterization and Application of Supramolecular Junctions

“…The studies of individual DNA junctions bonded through hydrogen bond, π‐π stacking interactions have also revealed a wealth of information on electron transport, [24, 60] thermoelectric effects [61] hybridization dynamics [62] et al. Moreover, recent studies have shown that DNA zipper structure not only has excellent electrical conductivity but more importantly exhibits self‐restoring capability, which is valuable for the constriction of feasible and reproducible molecular junctions [44b] …”

Chemical Sensors using Single‐Molecule Electrical Measurements

“…Schematic illustration of the scanning tunneling microscopy break junction (STM‐BJ) measurements. Reproduced with permission [107] . Copyright 2021, The Author(s).…”

Recent Advances in Single-Molecule Sensors Based on STM Break Junction Measurements

“…Since the inventions of break junction techniques, the electrical properties of oligonucleotides, including DNA [ 89 , 90 ], RNA [ 91 ] and RNA: DNA Hybrids [ 92 ], have been explored in the molecular junctions. It was found that the single-molecule conductance of these oligonucleotides is very sensitive to the molecular length [ 93 ], the helical conformation [ 94 ], the base sequence [ 95 ], and the environmental surroundings [ 96 ]. For instance, a single base pair mismatch in the short double stranded DNA (dsDNA) can cause the single-molecule conductance changing up by one order of magnitude [ 97 ].…”