Modulation of Molecular Flux Using a Graphene Nanopore Capacitor.
Modulation of Molecular Flux Using a Graphene Nanopore Capacitor.
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DOI：
10.1021/acs.jpcb.6b10574
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发表时间：
2017-04-20
期刊：
影响因子：
--
通讯作者：
Aksimentiev A
中科院分区：
文献类型：
--
作者：
Shankla M;Aksimentiev A
调节流经纳米级孔隙的离子电流是基本的生物过程之一。受大自然的启发，合成固态膜中的纳米孔正在开发中，以实现生物大分子的快速分析并作为纳米流体回路的元件。在这里，我们从理论上研究了离子和水通过含有单个充满电解质的纳米孔的石墨烯-绝缘体-石墨烯膜的传输。通过全原子分子动力学模拟，我们表明这种石墨烯纳米孔电容器的电荷状态可以调节纳米孔离子电流的选择性和大小。在固定的跨膜偏压下，离子电流可以从由阳离子和阴离子的等量混合物承载切换为几乎完全由阳离子或阴离子物质承载，具体取决于分配给电容器两个极板的电荷符号。将电容器的极板分配相反符号的电荷可以增加纳米孔电流或显着减少纳米孔电流，具体取决于驱动跨膜电流的偏压的极性。通过纳米孔表面电荷的动态反转，尽管纳米孔的物理尺寸比电解质的屏蔽长度大一个数量级，但发现这种离子电流调制仍然发生。离子电流整流伴随着明显的电渗效应，可以将中性分子（例如蛋白质和药物）穿过固态膜，从而充当电子和化学信号之间的界面。
Modulation of ionic current flowing through nanoscale pores is one of the fundamental biological processes. Inspired by nature, nanopores in synthetic solid-state membranes are being developed to enable rapid analysis of biological macromolecules and to serve as elements of nanofludic circuits. Here, we theoretically investigate ion and water transport through a graphene-insulator-graphene membrane containing a single, electrolyte-filled nanopore. By means of all-atom molecular dynamics simulations we show that the charge state of such a graphene nanopore capacitor can regulate both the selectivity and the magnitude of the nanopore ionic current. At a fixed transmembrane bias, the ionic current can be switched from being carried by an equal mixture of cations and anions to being carried almost exclusively by either cationic or anionic species, depending on the the sign of the charge assigned to both plates of the capacitor. Assigning the plates of the capacitor opposite sign charges can either increase the nanopore current or reduce it substantially, depending on the polarity of the bias driving the transmembrane current. Facilitated by dynamic inversion of the nanopore surface charge, such ionic current modulations are found to occur despite the physical dimensions of the nanopore being an order of magnitude larger than the screening length of the electrolyte. The ionic current rectification is accompanied by a pronounced electro-osmotic effect that can transport neutral molecules such as proteins and drugs across the solid-state membrane and thereby serve as an interface between electronic and chemical signals.
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影响因子：
56.9
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对 Na 和 K 具有电压可调离子选择性的仿生石墨烯纳米孔
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