Design of Multifunctional Nanopore Using Polyampholyte Brush with Composition Gradient
Design of Multifunctional Nanopore Using Polyampholyte Brush with Composition Gradient
复制标题
DOI：
10.1021/acsnano.1c05543
复制
发表时间：
2021-11-23
期刊：
影响因子：
17.1
通讯作者：
Szleifer, Igal
中科院分区：
文献类型：
--
作者：
Qin, Shiyi;Huang, Kai;Szleifer, Igal
生物纳米孔内的分子组织和电荷模式通过进化进行优化，以增强离子和分子的传输。受核孔复合体采用不对称排列的无序蛋白质作为其门控的启发，我们设计了一个由不对称聚两性离子刷包裹的人工纳米孔作为模型系统来研究纳米限制下的非对称质量传输。发展了一个非平衡稳态分子理论来解释弱聚两性离子的复杂电荷调节效应，并解决了聚合物构象与外加电场之间的耦合。在这种最先进的理论方法的基础上，我们对纳米孔内的刺激响应结构行为和输运性质进行了全面的理论描述，并考虑了所有的分子细节。我们的模型表明，通过在纳米孔的聚合物涂层中加入pH敏感性的梯度，可以实现各种不对称的电荷模式和功能结构，以pH响应的方式允许在所设计的系统中实现多种功能。纳米孔内部的不对称电荷模式导致了对主要载流子的静电陷阱，在优化的pH和盐浓度下，纳米孔变成了整流因子超过1000的离子整流器。我们的理论进一步预测，纳米孔设计的行为就像一个双门纳米流体设备，具有pH触发的门的打开，可以用作离子泵和pH响应的分子过滤器。这些结果加深了我们对纳米受限体系中不对称输运的理解，并为设计聚合物涂层的智能纳米孔提供了指导。
Molecular organizations and charge patterns inside biological nanopores are optimized by evolution to enhance ionic and molecular transport. Inspired by the nuclear pore complex that employs asymmetrically arranged disordered proteins for its gating, we here design an artificial nanopore coated by an asymmetric polyampholyte brush as a model system to study the asymmetric mass transport under nano-confinement. A nonequilibrium steady-state molecular theory is developed to account for the intricate charge regulation effect of the weak polyampholyte and to address the coupling between the polymer conformation and the external electric field. On the basis of this state-of-the-art theoretical method, we present a comprehensive theoretical description of the stimuli-responsive structural behaviors and transport properties inside the nanopore with all molecular details considered. Our model demonstrates that by incorporating a gradient of pH sensitivity into the polymer coatings of the nanopore, a variety of asymmetric charge patterns and functional structures can be achieved, in a pH-responsive manner that allows for multiple functions to be implemented into the designed system. The asymmetric charge pattern inside the nanopore leads to an electrostatic trap for major current carriers, which turns the nanopore into an ionic rectifier with a rectification factor above 1000 at optimized pH and salt concentration. Our theory further predicts that the nanopore design behaves like a double-gated nanofluidic device with pH-triggered opening of the gates, which can serve as an ion pump and pH-responsive molecular filter. These results deepen our understanding of asymmetric transport in nanoconfined systems and provide guidelines for designing polymer-coated smart nanopores.