Contribution of oxygen reduction to charge injection on platinum and sputtered iridium oxide neural stimulation electrodes.
Contribution of oxygen reduction to charge injection on platinum and sputtered iridium oxide neural stimulation electrodes.
复制标题
DOI：
10.1109/tbme.2010.2050690
复制
发表时间：
2010-09
期刊：
影响因子：
--
通讯作者：
Shire DB
中科院分区：
文献类型：
--
作者：
Cogan SF;Ehrlich J;Plante TD;Gingerich MD;Shire DB
在氧饱和生理盐水中，用循环伏安法和电压瞬变测量法研究了溅射氧化铱(SIROF)电极和铂神经刺激电极上氧还原的程度。在慢扫描循环伏安法中，氧还原是铂电极上主要的电荷导纳反应，约占总电荷的88%，约为12mC/cm2。对于300 nm厚的SIROF电极，氧还原是一个很小的反应，贡献了1.3mC/cm2，约占总电荷的3%。在铂电极的电流脉冲过程中，观察到氧在总注入电荷的7%的水平上被还原。脉冲SIROF电极上没有氧还原的迹象。在穿透SIROF微电极(标称表面积为2000μm2)上观察到了氧还原对扫速的贡献，并将其解释为氧在电解液中渗透到绝缘层和电极轴之间的限速扩散。对于典型的神经刺激脉冲，在穿透SIROF微电极上不能观察到氧还原。根据体内溶解氧的浓度，估计铂微电极上的氧还原对总注入电荷的贡献不到0.5%，而在SIROF电极上的贡献要小得多。
The extent to which oxygen reduction occurs on sputtered iridium oxide (SIROF) and platinum neural stimulation electrodes was quantified by cyclic voltammetry and voltage-transient measurements in oxygen-saturated physiological saline. Oxygen reduction was the dominant charge-admittance reaction on platinum electrodes during slow-sweep-rate cyclic voltammetry, contributing ~12 mC/cm2 (88% of total charge) to overall cathodal charge capacity. For a 300-nm-thick SIROF electrode, oxygen reduction was a minor reaction contributing 1.3 mC/cm2, ~3% of total charge. During current pulsing with platinum electrodes, oxygen reduction was observed at a level of 7% of the total injected charge. There was no indication of oxygen reduction on pulsed SIROF electrodes. A sweep-rate-dependent contribution of oxygen reduction was observed on penetrating SIROF microelectrodes (nominal surface area 2000 μm2) and is interpreted in terms of rate-limited diffusion of oxygen in electrolyte that penetrates the junction between the insulation and electrode shaft. For typical neural stimulation pulses, no oxygen reduction could be observed on penetrating SIROF microelectrodes. Based on the in vivo concentration of dissolved oxygen, it is estimated that oxygen reduction on platinum microelectrodes will contribute less than 0.5% of the total injected charge and considerably less on SIROF electrodes.