Effects of access resistance on the resistive-pulse caused by translocating of a nanoparticle through a nanopore
Effects of access resistance on the resistive-pulse caused by translocating of a nanoparticle through a nanopore
复制标题
访问电阻对纳米粒子通过纳米孔移位引起的电阻脉冲的影响
DOI：
10.1039/c3ra46032k
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发表时间：
2014-01-01
期刊：
影响因子：
3.9
通讯作者：
Hu, Guoqing
中科院分区：
文献类型：
--
作者：
Wang, Junrong;Ma, Jian;Hu, Guoqing
最近的实验研究表明，具有低厚度与直径纵横比的纳米孔的进入阻力（AR）在颗粒移位中起重要作用。现有的理论通常只考虑孔隙系统中的AR而不考虑颗粒的存在。基于连续介质模型，我们系统地研究了纳米颗粒在不同纳米孔结构中移位引起的电流变化。根据数值结果，提出了一个分析模型来估计AR对连续脉冲幅度的影响，即，AR与孔隙阻力的比值。电流的变化是第一次预测我们的模型的纳米粒子和纳米孔具有广泛的尺寸范围内的中性表面电荷。随后，表面电荷的影响进行了研究。结果表明，连续脉冲的幅度随着纳米颗粒或纳米孔表面电荷的增加而减小。我们还发现，由于浓度极化，在低体相浓度下，位置相关的连续脉冲的形状可能会发生显著的畸变。这项研究提供了一个深刻的洞察AR在颗粒孔系统，并可能是有用的设计纳米孔为基础的检测设备。
Recent experimental studies showed that the access resistance (AR) of a nanopore with a low thickness-to-diameter aspect ratio plays an important role in particle translocation. The existing theories usually only consider the AR without the presence of particles in the pore systems. Based on the continuum model, we systematically investigate the current change caused by nanoparticle translocation in different nanopore configurations. From numerical results, an analytical model is proposed to estimate the influence of the AR on the resistive-pulse amplitude, i.e., the ratio of the AR to the pore resistance. The current change is first predicted by our model for nanoparticles and nanopores with a wide range of sizes at the neutral surface charge. Subsequently, the effect of surface charges is studied. The results show that resistive-pulse amplitude decreases with the increasing surface charge of the nanoparticle or the nanopore. We also find that the shape of the position-dependent resistive-pulse might be distorted significantly at low bulk concentration due to concentration polarization. This study provides a deep insight into the AR in particle-pore systems and could be useful in designing nanopore-based detection devices.