Zhu Junliang, Qiu Hu, Guo Wanlin
Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education, State Key Laboratory of Mechanics and Control for Aerospace Structures, Institute for Frontier Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
Natl Sci Rev. 2024 Jul 13;11(8):nwae242. doi: 10.1093/nsr/nwae242. eCollection 2024 Aug.
Reproducing the outstanding selectivity achieved by biological ion channels in artificial channel systems can revolutionize applications ranging from membrane filtration to single-molecule sensing technologies, but achieving this goal remains a challenge. Herein, inspired by the selectivity filter structure of the KcsA potassium channel, we propose a design of biomimetic potassium nanochannels by functionalizing the wall of carbon nanotubes with an array of arranged carbonyl oxygen atoms. Our extensive molecular dynamics simulations show that the biomimetic nanochannel exhibits a high K permeation rate along with a high K/Na selectivity ratio. The free energy calculations suggest that the low Na permeability is the result of the higher energy barrier for Na than K at the channel entrance and ion binding sites. In addition, reducing the number of ion binding sites leads to an increase in the permeation rate but a decrease in selectivity. These findings not only hold promise for the design of high-performance membranes but also help understand the mechanism of selective ion transport in biological ion channels.
在人工通道系统中重现生物离子通道所实现的卓越选择性，可彻底改变从膜过滤到单分子传感技术等一系列应用，但实现这一目标仍然是一项挑战。在此，受KcsA钾通道选择性过滤器结构的启发，我们提出了一种通过用排列有序的羰基氧原子阵列对碳纳米管壁进行功能化来设计仿生钾纳米通道的方法。我们广泛的分子动力学模拟表明，该仿生纳米通道具有高钾渗透速率以及高钾/钠选择性比。自由能计算表明，低钠渗透性是由于通道入口和离子结合位点处钠的能垒高于钾。此外，减少离子结合位点的数量会导致渗透速率增加，但选择性降低。这些发现不仅为高性能膜的设计带来了希望，也有助于理解生物离子通道中选择性离子传输的机制。
