Charge transfer and stability of implantable electrodes on flexible substrate

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• 作者：M.M.R. Howlader^a ; ^{mrhowlader@ece.mcmaster.ca}Author Vitae ; T.E. Doyle^aAuthor Vitae ; S. Mohtashami^aAuthor Vitae ; J.R. Kish^bAuthor Vitae
• 关键词：Electrochemical impedance ; Surface roughness ; Liquid crystal polymer ; Charge transfer ; Implantable electrodes ; Neuromuscular stimulation
• 刊名：Sensors and Actuators B: Chemical
• 出版年：2013
• 出版时间：1 March, 2013
• 年：2013
• 卷：178
• 期：Complete
• 页码：132-139
• 全文大小：1138 K

文摘

Beyond their biocompatibility, implanted electrodes for neuromuscular stimulation require careful consideration of conductivity, stability, and charge delivery capacity (CDC) to avoid irreversible faradaic reactions. To study these requirements, metal electrodes of platinum (Pt), gold (Au), and titanium (Ti) on flexible liquid crystal polymer are fabricated using electron-beam evaporation, and investigated by electrochemical impedance spectroscopy, cyclic voltammetry and atomic force microscopy. A theoretical model is used to explain the physical functionalities. Frequency dependent electrochemical interfacial impedance is observed. The impedance as well as long-term electrochemical stability is influenced by the surface roughness, reactivity and capacitance of the electrodes. Pt electrode offers lower impedance in the neuromuscular stimulation frequencies and higher CDC than that of Ti and Au, but is not as stable as Au electrode.