Particle Trajectory-Dependent Ionic Current Blockade in Low-Aspect-Ratio Pores
Particle Trajectory-Dependent Ionic Current Blockade in Low-Aspect-Ratio Pores
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DOI：
10.1021/acsnano.5b05906
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发表时间：
2016-01-01
期刊：
影响因子：
17.1
通讯作者：
Kawai, Tomoji
中科院分区：
文献类型：
--
作者：
Tsutsui, Makusu;He, Yuhui;Kawai, Tomoji
使用具有低厚度与直径纵横比结构的纳米孔的电阻脉冲感测有望能够对液体中的纳米级物体进行高空间分辨率分析。在这里，我们通过监测聚合物纳米珠易位过程中的离子电流封锁来研究低纵横比孔隙传感器的传感能力。我们检测到许多小电流尖峰，这是由于孔口被扩散到其中的颗粒部分堵塞，反映了低纵横比孔的扩展电感应区。我们还发现粒子捕获阶段的离子流线形状存在很大变化，这表明吸入孔中的粒子具有随机入射角。与此形成鲜明对比的是，由于孔隙中的空间限制有效地将随机捕获动力学限制为明确的弹道运动，因此离子分布在后易位状态下具有高度可重复性。这些结果与多物理场模拟一起表明，电阻脉冲高度高度依赖于超薄孔隙传感器中涉及的纳米级单粒子轨迹。目前的发现表明调节低纵横比孔隙中分析物的易位途径对于提高液体中单生物粒子断层扫描的辨别能力非常重要。
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.