Application of recognition tunneling in single molecule identification

Single molecule identification is one essential application area of nanotechnology. The application areas including DNA sequencing, peptide sequencing, early disease detection and other industrial applications such as quantitative and quantitative analysis of impurities, etc. The recognition tunneling technique we have developed shows that after functionalization of the probe and substrate of a conventional Scanning Tunneling Microscope with recognition molecules ("tethered molecule-pair" configuration), analyte molecules trapped in the gap that is formed by probe and substrate will bond with the reagent molecules. The stochastic bond formation/breakage fluctuations give insight into the nature of the intermolecular bonding at a single molecule-pair level. The distinct time domain and frequency domain features of tunneling signals were extracted from raw signals of analytes such as amino acids and their enantiomers. The Support Vector Machine (a machine-learning method) was used to do classification and predication based on the signal features generated by analytes, giving over 90% accuracy of separation of up to seven analytes. This opens up a new interface between chemistry and electronics with immediate implications for rapid Peptide/DNA sequencing and molecule identification at single molecule level.