Tunneling is greatly enhanced when specific chemical contacts are made between metal electrodes and a molecule.1 Remarkably, the effect appears to be quite significant even for weak (but specific) interactions like hydrogen bonds.2 We have measured tunnel transport in DNA molecules connected to electrodes via specific hydrogen bonds, finding a significant tunnel conductance. Thus, the combination of tunneling with specific cognate ligands might enable a new form of highly sensitive detector for mapping the chemical composition of single molecules.
1. X.D. Cui, A. Primak, X. Zarate, J. Tomfohr, O.F. Sankey, A.L. Moore, T.A. Moore, D. Gust, H. G. and S.M. Lindsay, Reproducible measurement of single-molecule conductivity, Science, 2001. 294: 571-574.
2. T. Ohshiro and Y. Umezawa, Complementary base-pair-facilitated electron tunneling for electrically pinpointing complementary nucleobases, Proc. Nat. Acad. Sci., 2006. 103: 10-14.
|