Failure Mechanisms of a Gold Microelectrode in Bioelectronics Applications

Jonghun Kim,Sang-Hee Yoon

doi:10.1155/2015/792198

Abstract

The generation, growth, and collapse of tiny bubbles are inevitable for a microelectrode working in aqueous environment, thus resulting in physical damages on the microelectrode. The failure mechanisms of a microelectrode induced by tiny bubble collapsing are investigated by generating tiny hydrogen bubbles on a gold microelectrode through deionized water electrolysis. The surface of the microelectrode is modified with a thiol-functionalized arginine-glycine-aspartic acid peptide to generate perfectly spherical bubbles in proximity of the surface. The failure of an Au microelectrode is governed by two damage mechanisms, depending on the thickness of the microelectrode: a water-hammer pressure due to the violent collapse of a single large bubble, formed through merging of small bubbles, for ultrathin Au microelectrodes of 40–60 nm in thickness, and an energy accumulation resulting from the repetitive collapse of tiny bubbles for thick Au microelectrodes of 100–120 nm.

Highlights

Bioelectronics creates innovative devices or processes for the diagnosis, treatment, prognosis, and prevention of diseases through the application of electrical engineering principles to biology or medicine
An electrolysis of DI water produced tiny hydrogen bubbles with an average radius of 19.1–38.9 μm on the Au microelectrode surface modified with a thiol-functionalized RGD by electrolyzing when applied voltage was adjusted at a range of 1.6 V to 7.0 V
Two failure mechanisms of Au microelectrodes that are commonly used in bioelectronics applications have been characterized by generating and collapsing tiny hydrogen bubbles in proximity of the surface of the Au microelectrodes through deionized water electrolysis

Summary

Introduction

Bioelectronics creates innovative devices or processes for the diagnosis, treatment, prognosis, and prevention of diseases through the application of electrical engineering principles to biology or medicine. An enormous concentration of energy resulting from bubble collapse is known to be responsible for the occurrence of microscopic damages on a microelectrode [1] and the deleterious effects on a biological system (e.g., hemolysis, renal injury, etc.) [2, 3]. This phenomenon is restricted to bioelectronics, and frequently involves a variety of macroscale engineering applications (e.g., pumps, turbines, propellers, bearings, etc.) [4, 5] to nano-/microscale ones (e.g., nano-/microelectromechanical systems (N/MEMS), semiconductors, etc.) [6, 7]. The reason is that this problem is related to unsteady two-phase flow combined with the reaction of the specific material of which a substrate is made

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Conclusion