A flexible Ag/AgCl micro reference electrode based on a parylene tube structure

SENSORS AND ACTUATORS B-CHEMICAL

卷:247

Article

Zhao, Zhiguo¹  Tu, Hongen¹  Kim, Eric G. R.^1,2  Sloane, Bonnie F.³  Xu, Yong¹ 

[1] Wayne State Univ, Dept Elect & Comp Engn, Detroit, MI 48202 USA

[2] Wayne State Univ, Dept Biomed Engn, Detroit, MI USA

[3] Wayne State Univ, Dept Pharmacol, Detroit, MI 48201 USA

关键词: MEMS;    Reference electrode;    Parylene tube;    pH sensor;    Iridium oxide;   

DOI  :  10.1016/j.snb.2017.02.135

来源: Elsevier

【 摘 要 】

In the effort of developing micro-electrochemical sensors, the miniaturization of reference electrodes has been a challenging task. In this paper, a flexible micro reference electrode with an internal electrolyte reservoir is reported. This new device is based on a unique microfabricated parylene tube structure, which is filled with Cl-rich electrolyte, into which a 50 mu m diameter silver (Ag) wire covered with a 7.4 mu m thick silver chloride (AgCl) layer is inserted. The distal end of the tube is filled with potassium chloride (KCl) saturated agarose gel. The Ag wire, thick AgCl layer, and internal electrolyte reservoir lead to a long operation time and a stable reference voltage. The drift over a 10-h period has been found to be less than 2 mV. The total operation time of the device has exceeded 100 h. Furthermore, the compatibility with microfabrication allows the integration of other components, leading to truly miniaturized electrochemical sensors or sensing systems. To prove this, we demonstrated a pH sensor by combining the reference electrode and an iridium oxide electrode monolithically integrated on the surface of the parylene tube. (C) 2017 Elsevier B.V. All rights reserved.

【 授权许可】

Free