Bioinspired Graphene Nanopores with Voltage-Tunable Ion Selectivity for Na+ and K+
Bioinspired Graphene Nanopores with Voltage-Tunable Ion Selectivity for Na+ and K+
复制标题
对 Na 和 K 具有电压可调离子选择性的仿生石墨烯纳米孔
DOI：
10.1021/nn4043628
复制
发表时间：
2013-11-01
期刊：
影响因子：
17.1
通讯作者：
Corry, Ben
中科院分区：
文献类型：
--
作者：
He, Zhongjin;Zhou, Jian;Corry, Ben
生物蛋白质通道具有门控性、高渗透性和选择性等特点，这促使研究者们不断地模拟其功能以用于实际应用。在此，使用分子动力学模拟，我们在石墨烯片中设计了生物启发的纳米孔，可以区分Na+和K+，这两种离子具有非常相似的特性。模拟结果表明，在跨膜电压偏置下，含有四个羰基的纳米孔模拟KcsA K+通道的选择性过滤器优先传导K+而不是Na+。由四个带负电荷的羧酸酯基团官能化以模拟NavAb Na+通道的选择性过滤器的纳米孔选择性地结合Na+，但相对于Na+转运K+。令人惊讶的是，含有三个羧酸根基团的较小直径孔的离子选择性可以通过改变所施加的偏压的大小来调节。在较低的电压偏置下，它以单列方式传输离子，并表现出Na+选择性，这取决于敲击离子传导和Na+的选择性阻断。在更高的电压偏压下，纳米孔是K+选择性的，因为Na+的阻断是不稳定的，并且与K+相比，对羧酸根基团的更强亲和力减缓了Na+的通过。仿生离子选择性纳米孔的计算设计有助于理解生物离子通道的选择性机制，也可能导致广泛的潜在应用，如敏感的离子传感器，用于Na+/K+分离的纳滤膜，和电压可调的纳米流体装置。
Biological protein channels have many remarkable properties such as gating, high permeability, and selectivity, which have motivated researchers to mimic their functions for practical applications. Herein, using molecular dynamics simulations, we design bioinspired nanopores in graphene sheets that can discriminate between Na+ and K+, two ions with very similar properties. The simulation results show that, under transmembrane voltage bias, a nanopore containing four carbonyl groups to mimic the selectivity filter of the KcsA K+ channel preferentially conducts K+ over Na+. A nanopore functionalized by four negatively charged carboxylate groups to mimic the selectivity filter of the NavAb Na+ channel selectively binds Na+ but transports K+ over Na+. Surprisingly, the ion selectivity of the smaller diameter pore containing three carboxylate groups can be tuned by changing the magnitude of the applied voltage bias. Under lower voltage bias, it transports ions in a single-file manner and exhibits Na+ selectivity, dictated by the knock-on ion conduction and selective blockage by Na+. Under higher voltage bias, the nanopore is K+-selective, as the blockage by Na+ is destabilized and the stronger affinity for carboxylate groups slows the passage of Na+ compared with K+. The computational design of biomimetic ion-selective nanopores helps to understand the mechanisms of selectivity in biological ion channels and may also lead to a wide range of potential applications such as sensitive ion sensors, nanofiltration membranes for Na+/K+ separation, and voltage-tunable nanofluidic devices.