Morikawa Takanori, Yokota Kazumichi, Tanimoto Sachie, Tsutsui Makusu, Taniguchi Masateru
The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki 567-0047, Japan.
Sensors (Basel). 2017 Apr 18;17(4):885. doi: 10.3390/s17040885.
Label-free detection of single-nucleotides was performed by fast tunneling current measurements in a polar solvent at 1 MHz sampling rate using SiO₂-protected Au nanoprobes. Short current spikes were observed, suggestive of trapping/detrapping of individual nucleotides between the nanoelectrodes. The fall and rise features of the electrical signatures indicated signal retardation by capacitance effects with a time constant of about 10 microseconds. The high temporal resolution revealed current fluctuations, reflecting the molecular conformation degrees of freedom in the electrode gap. The method presented in this work may enable direct characterizations of dynamic changes in single-molecule conformations in an electrode gap in liquid.
使用二氧化硅保护的金纳米探针，通过在极性溶剂中以1 MHz采样率进行快速隧穿电流测量，实现了单核苷酸的无标记检测。观察到短电流尖峰，表明单个核苷酸在纳米电极之间的捕获/去捕获。电信号的下降和上升特征表明电容效应导致信号延迟，时间常数约为10微秒。高时间分辨率揭示了电流波动，反映了电极间隙中分子构象的自由度。这项工作中提出的方法可能使人们能够直接表征液体中电极间隙中单分子构象的动态变化。
