15:30 〜 15:45
▲ [24p-E104-9] Single-Molecule Classification based on Intermolecular Hydrogen Bond by Modified Nano-Gap
キーワード：Single-molecule measurement
The development of detection/identification methods for amino acids is an important issue for understanding biological systems. Until now, there have been few analytical methods for amino-acid molecules because of limited selectivity and low detection limits. Single-molecule electrical measurement by nano-gap is one of the promising candidates for detection/identification of amino acid molecules. In this study, we focused on detecting L-aspartic acid (Asp), a target molecule for the diagnosis of several diseases. We utilized hydrogen-bond facilitated quantum tunneling enhancement for single-molecule electrical measurements by using mercaptoacetic acid (MAA) modified nano-gap. The measured current was investigated by machine learning based time series analysis method for accurate amino acid discrimination. Compared to measurements using bare nano-gap, it is found that MAA modification improves the difference in the conductance-time profiles between Asp and L-leucine (Leu) through the hydrogen bond facilitated tunneling phenomena for Asp, and not for Leu. We found that the accuracy of discrimination with MAA is 0.99 using over thirteen conductance signals. It is also found that this method enables determination of concentration even in the mixture of Asp and Leu. The method demonstrates the improvement of selective analysis for amino acids so that this will be potentially applicable for medical application, diagnosis and single-molecule peptide sequencer.