化学学报 ›› 2017, Vol. 75 ›› Issue (9): 873-877.DOI: 10.6023/A17050216 上一篇    下一篇

研究论文

纳米多孔金的单分子层门控离子输运性质研究

闫娜娜, 肖天亮, 刘兆阅   

  1. 北京航空航天大学化学学院 北京 100191
  • 收稿日期:2017-05-17 出版日期:2017-09-15 发布日期:2017-09-04
  • 通讯作者: 刘兆阅 E-mail:liuzy@buaa.edu.cn
  • 基金资助:

    国家自然科学基金(No.21571011)和国家重点基础研究发展计划(No.2014CB931803)资助.

Monolayer-gated Ion Transport in Artificial Ion Channels Based on A Nanoporous Gold Membrane

Yan Nana, Xiao Tianliang, Liu Zhaoyue   

  1. School of Chemistry, Beihang University, Beijing 100191
  • Received:2017-05-17 Online:2017-09-15 Published:2017-09-04
  • Contact: 10.6023/A17050216 E-mail:liuzy@buaa.edu.cn
  • Supported by:

    Project supported by the National Natural Science Foundation of China (No. 21571011) and the National Basic Research Program of China (No. 2014CB931803).

生物离子通道能够对环境刺激作出响应,有效地调节细胞内外的物质平衡,保证体内的正常生命活动.研究具有生物离子通道功能的人工离子通道对发展离子开关具有重要的意义.本工作利用电化学去合金法制备了具有三维通道结构的纳米多孔金膜,并将其应用于离子通道,研究其离子输运性质.在电场作用下,纳米多孔金由于发生极化而使通道表现出离子整流性质.在纳米多孔金表面修饰十二烷基硫醇单分子层,利用其疏水效应,通道能够阻止离子的传输,使其处于“关闭”态.溶液中的化学刺激如表面活性剂能够增强电解质溶液在通道表面的浸润,有利于离子的传输,使通道处于“打开”态.这种单分子层修饰的纳米多孔金表现出表面活性剂响应的离子开关特性.

关键词: 离子通道, 去合金法, 纳米多孔金, 表面活性剂, 离子开关

Biological ion channels that intelligently control the transport of ions or molecules through the cell membrane in response to external stimuli can maintain the balance between the extracellular and intracellular substances, which ensures the normal life activities of the organism. The development of artificial ion channels with analogous function to the biological counterparts is of great significance because of their possible applications as ion switches and sensors. In this paper, we describe a new type of artificial ion channels based on de-alloyed nanoporous gold membrane with three-dimensional nanochannels. The nanochannels were built by electrochemical etching of gold-silver alloy in concentrated nitric acid. The surface morphology and component of nanoporous gold membrane were characterized by scanning electron microscope (SEM) and energy dispersive X-ray spectrum (EDX). The ion transport properties of artificial ion channels were characterized with current-voltage curves which was measured by a picoammeter. Our results indicate that this nanoporous gold membrane demonstrates an ion rectification phenomenon because of the electrochemical polarization of gold under an electric field. Subsequently, a layer of hydrophobic molecules was assembled on the surface of nanoporous gold membrane by strong Au-thiol bonds after immersed in the solution of 1-dodecanethiol. The measurements of water contact angles (CAs) indicated that the modification of 1-dodecanethiol molecules converted the surface water CA of nanoporous gold membrane from 36.5° to 120.6°. This hydrophobic monolayer prevents the transport of water-soluble ions, which makes the channels exist in an "off" state. The stimulus of surfactant in the electrolyte is favorable for the wetting of channel surface by aqueous electrolyte, which makes the channels exist in an "on" state for water-soluble ions. Therefore, the monolayer-modified nanoporous gold membrane can serve as a surfactant-gated ion switch. Our work provides a new idea for the preparation of artificial ion channels, which can be applied for intelligently responsive artificial system.

Key words: ion channel, de-alloying, nanoporous gold, surfactant, ion switch