Kishimoto Shohei, Murayama Sanae, Tsutsui Makusu, Taniguchi Masateru
The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan.
ACS Sens. 2020 Jun 26;5(6):1597-1603. doi: 10.1021/acssensors.0c00014. Epub 2020 Mar 18.
We investigated the temporal resolution of ionic current in solid-state nanopore sensors. Resistive pulses observed upon translocation of single-nanoparticles were found to become blunter as we imposed larger external resistance in series to the pore via the integrated microfluidic channels on the membrane. This was found to occur even when the out-of-pore resistance is more than an order of magnitude smaller than that at the nanopore, which can be understood as a predominant contribution of charging/discharging at the water-touching thin dielectrics to retard the response of the ionic current against ion blockage by a fast-moving object through the sensing zone. Most importantly, our results predict a time resolution of better than 12 ns, irrespective of the nanopore size, by optimizing the membrane capacitance and the external resistance that promises high-speed single-molecule sequencing by the ionic current at 10 base/s.
我们研究了固态纳米孔传感器中离子电流的时间分辨率。当我们通过膜上集成的微流控通道在纳米孔上串联施加更大的外部电阻时，发现单纳米颗粒转运时观察到的电阻脉冲变得更钝。即使孔外电阻比纳米孔处的电阻小一个数量级以上，也会出现这种情况，这可以理解为与水接触的薄电介质处的充电/放电起主要作用，从而延迟了离子电流对快速移动物体通过传感区造成的离子阻塞的响应。最重要的是，我们的结果预测，通过优化膜电容和外部电阻，无论纳米孔大小如何，时间分辨率都能优于12纳秒，这有望实现每秒10个碱基的离子电流高速单分子测序。
