Recognition tunneling.
Single molecules in a tunnel junction can now be interrogated reliably using chemically functionalized electrodes. Monitoring stochastic bonding fluctuations between a ligand bound to one electrode and its target bound to a second electrode ('tethered molecule-pair' configuration) gives insight into the nature of the intermolecular bonding at a single molecule-pair level, and defines the requirements for reproducible tunneling data. Simulations show that there is an instability in the tunnel gap at large currents, and this results in a multiplicity of contacts with a corresponding spread in the measured currents. At small currents (i.e. large gaps) the gap is stable, and functionalizing a pair of electrodes with recognition reagents (the 'free-analyte' configuration) can generate a distinct tunneling signal when an analyte molecule is trapped in the gap. This opens up a new interface between chemistry and electronics with immediate implications for rapid sequencing of single DNA molecules.
Lindsay
Stuart
S
Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA.
He
Jin
J
Sankey
Otto
O
Hapala
Prokop
P
Jelinek
Pavel
P
Zhang
Peiming
P
Chang
Shuai
S
Huang
Shuo
S
D004247:DNA / Q000032:analysis / Q000235:genetics; D006860:Hydrogen Bonding; D016252:Microscopy, Scanning Tunneling
D004247:DNA