Single-Molecule Analysis Methods Using Nanogap Electrodes and Their Application to DNA Sequencing Technologies

Single-molecule analysis methods facilitate the investigation of the properties of single-molecule junctions (SMJs), in which single molecules are connected between a pair of nanoelectrodes that use nanogap electrodes having a spacing of less than several nanometers. Various methods have been developed to investigate numerous useful parameters for SMJs; for example, the number of molecules connected between a pair of nanoelectrodes can be determined, the types and structures of single molecules can be revealed, localized temperatures within SMJs can be evaluated, and the Seebeck coefficient and the bond strength between single molecules and electrodes can be ascertained. Single-molecule analysis methods have also been used to analyze biopolymers in solutions, and this has resulted in single-molecule sequencing technologies being developed that can determine sequences of base molecules in DNA and RNA along with sequences of amino acids in peptides. Single-molecule analysis methods are expected to develop into digital analysis techniques that can be used to investigate the physical and chemical properties of molecules at single-molecule resolutions.