Acta Chim. Sinica ›› 2017, Vol. 75 ›› Issue (9): 873-877.DOI: 10.6023/A17050216 Previous Articles     Next Articles



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
  • 投稿日期:2017-05-17 发布日期:2017-09-04
  • 通讯作者: 刘兆阅
  • 基金资助:


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 Published:2017-09-04
  • Contact: 10.6023/A17050216
  • Supported by:

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

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