47th CEMS Colloquium

Title

Single-Molecule Analysis Method Using Nanogap Electrodes

Abstract

In this study, a single-molecule analysis method has been developed to investigate the structures and physical properties of molecules using single-molecule junctions wherein these molecules are bridged between nanogap electrodes. Currently, the number of molecules connected between nanogap electrodes can be detected based on electrical conductance. The structures and types of single molecules in single-molecule junctions can be identified using inelastic electron tunneling spectroscopy, which provides the vibrational spectrum of the junctions. In addition, the lifetime of the single-molecule junctions allows us to evaluate the local temperature of the junctions and strengths of the electrode–molecule bonds. Furthermore, the thermoelectric power was measured and the orbital symmetry rule for electron transport in single-molecule junctions was demonstrated.

Various single-molecule analysis methods have been applied in this study to analyze DNA, RNA, and peptides. One of our goals is to identify the sequences of base molecules in DNA and RNA and the sequences of amino acids in peptides by measuring electrical conductance of single molecules passing between nanogap electrodes. It can be noted that the proposed method can identify sequences of base molecules and amino acids at single-molecule resolutions. In addition, our method has succeeded in detecting various chemically modified base molecules and amino acids, many of which are very important diseases markers.