title: Particle Trajectory-Dependent Ionic Current Blockade in Low-Aspect-Ratio Pores.
abstract: Resistive pulse sensing with nanopores having a low thickness-to-diameter aspect-ratio structure is expected to enable high-spatial-resolution analysis of nanoscale objects in a liquid. Here we investigated the sensing capability of low-aspect-ratio pore sensors by monitoring the ionic current blockades during translocation of polymeric nanobeads. We detected numerous small current spikes due to partial occlusion of the pore orifice by particles diffusing therein reflecting the expansive electrical sensing zone of the low-aspect-ratio pores. We also found wide variations in the ion current line-shapes in the particle capture stage suggesting random incident angle of the particles drawn into the pore. In sharp contrast, the ionic profiles were highly reproducible in the post-translocation regime by virtue of the spatial confinement in the pore that effectively constricts the stochastic capture dynamics into a well-defined ballistic motion. These results, together with multiphysics simulations, indicate that the resistive pulse height is highly dependent on the nanoscopic single-particle trajectories involved in ultrathin pore sensors. The present finding indicates the importance of regulating the translocation pathways of analytes in low-aspect-ratio pores for improving the discriminability toward single-bioparticle tomography in liquid.
authors.affiliation: The Institute of Scientific and Industrial Research, Osaka University , 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
authors.forename: Makusu
authors.initials: M
authors.lastname: Tsutsui
authors.affiliation: School of Optical and Electronic Information, Huazhong University of Science and Technology , LuoYu Road, Wuhan 430074, China.
authors.forename: Yuhui
authors.initials: Y
authors.lastname: He
authors.affiliation: The Institute of Scientific and Industrial Research, Osaka University , 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
authors.forename: Kazumichi
authors.initials: K
authors.lastname: Yokota
authors.affiliation: The Institute of Scientific and Industrial Research, Osaka University , 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
authors.forename: Akihide
authors.initials: A
authors.lastname: Arima
authors.affiliation: Corporate Research & Development Center, Toshiba Corporation, Kawasaki, Kanagawa 212-8582, Japan.
authors.forename: Sadato
authors.initials: S
authors.lastname: Hongo
authors.affiliation: The Institute of Scientific and Industrial Research, Osaka University , 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
authors.forename: Masateru
authors.initials: M
authors.lastname: Taniguchi
authors.affiliation: The Institute of Scientific and Industrial Research, Osaka University , 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Washio
authors.affiliation: The Institute of Scientific and Industrial Research, Osaka University , 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan.
authors.forename: Tomoji
authors.initials: T
authors.lastname: Kawai
keywords: access resistance; ion transport; low aspect ratio; nanopore; single particle detection