Ion Gating in Nanopore Electrode Arrays with Hierarchically Organized pH-Responsive Block Copolymer Membranes
Ion Gating in Nanopore Electrode Arrays with Hierarchically Organized pH-Responsive Block Copolymer Membranes
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DOI：
10.1021/acsami.0c12926
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发表时间：
2020-12-09
影响因子：
9.5
通讯作者：
Bohn, Paul W.
中科院分区：
文献类型：
--
作者：
Baek, Seol;Kwon, Seung-Ryong;Bohn, Paul W.
受生物离子通道的启发，基于纳米孔的人工结构被开发用于智能离子/分子传输控制，在电子电子学和能量转换方面具有潜在的应用前景。纳米制造技术的进步使简单、通用的构建方法成为可能，而制造后的功能化使纳米通道具有独特的离子传输控制属性。在这里，我们表征了由聚苯乙烯-b-聚（4-乙烯基吡啶）（PS48400-b-P4VP(21300)）组成的ph响应，电荷选择双门控嵌段共聚物（BCP）膜，能够自组织成高度有序的纳米圆柱形结构域。由于PS-b-P4VP膜表现出pH依赖的结构转变，因此适合设计智能pH门控仿生通道，例如，在pH值接近P4VP的pK(a)时表现出开关传输切换，在pH < pK(a)时表现出优异的阴离子选择性。将BCP膜引入纳米孔电极阵列（BCP@NEAs）允许BCP作为ph响应门控制离子转移到NEA纳米孔。通过使用100 nm间隙双环纳米电极结构检测这种选择性传输和受限离子，该结构能够通过有效的氧化还原循环增强电流输出，放大系数为bbb10(2)。此外，BCP@NEAs表现出非凡的pH门控离子选择性，导致阴离子和阳离子探针在pH 3.0下的电流差异为3380倍。这种分层组织的bcp门控NEA系统可以作为开发其他刺激响应离子门的模板，例如基于温度和配体门控的离子门，从而利用NEAs的固有优势，例如基于氧化还原循环的增强灵敏度，这可能导致工程生物传感器和离子电子器件等技术应用。
Inspired by biological ion channels, artificial nanopore-based architectures have been developed for smart ion/molecular transport control with potential applications to iontronics and energy conversion. Advances in nanofabrication technology enable simple, versatile construction methods, and post-fabrication functionalization delivers nanochannels with unique ion transportcontrol attributes. Here, we characterize a pH-responsive, charge-selective dual-gating block copolymer (BCP) membrane composed of polystyrene-b-poly(4-vinylpyridine) (PS48400-b-P4VP(21300)), capable of self-organizing into highly ordered nanocylindrical domains. Because the PS-b-P4VP membrane exhibits pH-dependent structural transitions, it is suitable for designing intelligent pH-gated biomimetic channels, for example, exhibiting on-off transport switching at pH values near the pK(a) of P4VP with excellent anion permselectivity at pH < pK(a). Introducing the BCP membrane onto nanopore electrode arrays (BCP@NEAs) allows the BCP to serve as a pH-responsive gate controlling ion transfer into the NEA nanopores. Such selectively transported and confined ions are detected by using a 100 nm gap dual-ring nanoelectrode structure capable of enhancing current output by efficient redox cycling with an amplification factor >10(2). In addition, BCP@NEAs exhibit extraordinary pH-gated ion selectivity, resulting in a 3380-fold current difference between anion and cation probes at pH 3.0. This hierarchically organized BCP-gated NEA system can serve as a template for the development of other stimulus-responsive ion gates, for example, those based on temperature and ligand gating, thus exploiting the intrinsic advantages of NEAs, such as enhanced sensitivity based on redox cycling, which may lead to technological applications such as engineered biosensors and iontronic devices.