Synthetic cation-selective nanotube: Permeant cations chaperoned by anions
Synthetic cation-selective nanotube: Permeant cations chaperoned by anions
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DOI：
10.1063/1.3524310
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发表时间：
2011-01-28
影响因子：
4.4
通讯作者：
Chung, Shin-Ho
中科院分区：
文献类型：
--
作者：
Hilder, Tamsyn A.;Gordon, Dan;Chung, Shin-Ho
设计离子选择性合成纳米管模仿生物离子通道的能力可能对未来治疗细菌，疾病和作为超灵敏生物传感器具有重要意义。我们提出了一种由碳原子制成的合成纳米管的设计，该纳米管选择性地允许一价阳离子移动并拒绝所有阴离子。阳离子选择性纳米管模仿了生物离子通道的一些显著特性。在实际的纳米器件成功制造之前，进行概念验证计算研究是至关重要的。考虑到这一点，我们使用分子和随机动力学模拟来表征离子渗透穿过单壁（10，10），36埃长，碳纳米管终止与羧酸的有效半径为5.08埃的动态。虽然阳离子遇到了7 kT的高能势垒，但其高度被纳米管中的氯离子大幅降低。因此，孔入口附近氯离子的存在使得阳离子能够进入孔，并且一旦在孔中，它就被驻留的阳离子陪伴穿过窄孔。伴随的阳离子通过孔的那一刻，阳离子移回入口以运送另一个离子。合成的纳米管具有124 pS的高钠电导率，并显示出线性的电流-电压和电流-浓度曲线。阳离子-阴离子选择性比范围为8至25，取决于储层中的离子浓度。(C)2011年美国物理学会。[doi：10.1063/1.3524310]
The ability to design ion-selective, synthetic nanotubes which mimic biological ion channels may have significant implications for the future treatment of bacteria, diseases, and as ultrasensitive biosensors. We present the design of a synthetic nanotube made from carbon atoms that selectively allows monovalent cations to move across and rejects all anions. The cation-selective nanotube mimics some of the salient properties of biological ion channels. Before practical nanodevices are successfully fabricated it is vital that proof-of-concept computational studies are performed. With this in mind we use molecular and stochastic dynamics simulations to characterize the dynamics of ion permeation across a single-walled (10, 10), 36 angstrom long, carbon nanotube terminated with carboxylic acid with an effective radius of 5.08 angstrom. Although cations encounter a high energy barrier of 7 kT, its height is drastically reduced by a chloride ion in the nanotube. The presence of a chloride ion near the pore entrance thus enables a cation to enter the pore and, once in the pore, it is chaperoned by the resident counterion across the narrow pore. The moment the chaperoned cation transits the pore, the counterion moves back to the entrance to ferry another ion. The synthetic nanotube has a high sodium conductance of 124 pS and shows linear current-voltage and current-concentration profiles. The cation-anion selectivity ratio ranges from 8 to 25, depending on the ionic concentrations in the reservoirs. (C) 2011 American Institute of Physics. [doi:10.1063/1.3524310]