Electron transfer processes occurring on platinum neural stimulating electrodes: calculated charge-storage capacities are inaccessible during applied stimulation.
Electron transfer processes occurring on platinum neural stimulating electrodes: calculated charge-storage capacities are inaccessible during applied stimulation.
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DOI：
10.1088/1741-2552/aa6945
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发表时间：
2017-08
影响因子：
4
通讯作者：
Mortimer JT
中科院分区：
文献类型：
--
作者：
Hudak EM;Kumsa DW;Martin HB;Mortimer JT
使用铂电极的神经假体通常受到称为香农极限的电荷/电荷密度参数的限制。在检查电荷注入和观察到的组织损伤之间的关系时，应考虑电极-组织界面处的电化学。电荷存储容量 (CSC) 通常用作电极在刺激期间可以注入多少电荷的预测指标，但根据水窗上的稳态 i-E 曲线（循环伏安图）计算电荷会错误地反映电极在刺激期间的工作方式。我们的目标是深入了解为什么经典 i-E 曲线的 CSC 预测高估了神经刺激脉冲期间可注入的电荷量。在这项研究中，我们使用标准电化学技术来研究铂电化学如何取决于电极所获得的电位和电解质成分。实验表明：1）铂电极必须经过“清洗”程序，以暴露最大数量的表面铂位点用于氢吸附； 2) 在典型的神经刺激条件下，“清洁”的铂表面可能会恢复到阻塞状态； 3）神经刺激条件下可能会发生不可逆的氧还原，因此应考虑该反应的后果； 4) 氯离子 (Cl−) 或蛋白质（牛血清白蛋白）的存在会抑制氧化物形成并改变 H 吸附。这些观察结果有助于解释为什么传统的 CSC 计算高估了神经刺激期间可以注入的电荷。结果强调了对电极-电解质界面进行仔细的电化学检查可以在施加刺激期间对电极性能进行更准确的预期。
Neural prostheses employing platinum electrodes are often constrained by a charge/charge-density parameter known as the Shannon limit. In examining the relationship between charge injection and observed tissue damage, the electrochemistry at the electrode-tissue interface should be considered. The charge-storage capacity (CSC) is often used as a predictor of how much charge an electrode can inject during stimulation, but calculating charge from a steady-state i-E curve (cyclic voltammogram) over the water window misrepresents how electrodes operate during stimulation. We aim to gain insight into why CSC predictions from classic i-E curves overestimate the amount of charge that can be injected during neural stimulation pulsing. In this study, we use a standard electrochemical technique to investigate how platinum electrochemistry depends on the potentials accessed by the electrode and on the electrolyte composition. The experiments indicate: 1) platinum electrodes must be subjected to a “cleaning” procedure in order to expose the maximum number of surface platinum sites for hydrogen adsorption; 2) the “cleaned” platinum surface will likely revert to an obstructed condition under typical neural stimulation conditions; 3) irreversible oxygen reduction may occur under neural stimulation conditions, so the consequences of this reaction should be considered; and 4) the presence of the chloride ion (Cl−) or proteins (bovine serum albumin) inhibits oxide formation and alters H adsorption. These observations help explain why traditional CSC calculations overestimate the charge that can be injected during neural stimulation. The results underscore how careful electrochemical examination of the electrode-electrolyte interface can result in more accurate expectations of electrode performance during applied stimulation.
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影响因子：
9.7
作者：
Baek, Sungchul;Green, Rylie A.;Poole-Warren, Laura A.
通讯作者：
Poole-Warren, Laura A.
影响因子：
4.5
作者：
BIEGLER, T;RAND, DAJ;WOODS, R
通讯作者：
WOODS, R
影响因子：
4.5
作者：
BAGOTZKY, VS;VASSIYEV, YB;PIRTSKHA.JN
通讯作者：
PIRTSKHA.JN
影响因子：
3
作者：
Cogan, SF;Guzelian, AA;McCreery, DB
通讯作者：
McCreery, DB
影响因子：
7.4
作者：
ANSON, FC;KING, DM
通讯作者：
KING, DM