Improving impedance of implantable microwire multi-electrode arrays by ultrasonic electroplating of durable platinum black.
Improving impedance of implantable microwire multi-electrode arrays by ultrasonic electroplating of durable platinum black.
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DOI：
10.3389/fneng.2010.00005
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Potter SM
中科院分区：
文献类型：
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作者：
Desai SA;Rolston JD;Guo L;Potter SM
植入式微电极阵列（MEA）已成为神经刺激和记录实验的布恩。市售MEA由于其低表面积和小尖端直径而具有高阻抗，这适合于记录单个单元活性。降低电极阻抗但保持小直径将提供许多优点，包括降低刺激电压、降低刺激伪影和改善信噪比。阻抗降低可以通过用铂（Pt）黑电镀MEA来实现，这增加了表面积，但对电极的物理范围几乎没有影响。然而，由于铂黑电镀的耐久性低，这种方法长期使用并不流行。超声波电镀（即在超声波搅拌下电镀）已被证明可以改善用于循环伏安法的宏观电极的基底金属上的Pt黑的耐久性。这种方法以前没有被表征为用于慢性神经植入物的MEA。我们在这里表明，超声波电镀可以降低一个数量级或更多（取决于电镀的时间和电压）的微丝多电极阵列（MMEA）的阻抗，与脉冲电镀或传统的DC方法相比，具有更好的耐久性。我们还显示了与高阻抗未电镀电极相比，在体内植入研究中使用超声电镀低阻抗MMEAs可以实现更好的刺激和记录性能。
Implantable microelectrode arrays (MEAs) have been a boon for neural stimulation and recording experiments. Commercially available MEAs have high impedances, due to their low surface area and small tip diameters, which are suitable for recording single unit activity. Lowering the electrode impedance, but preserving the small diameter, would provide a number of advantages, including reduced stimulation voltages, reduced stimulation artifacts and improved signal-to-noise ratio. Impedance reductions can be achieved by electroplating the MEAs with platinum (Pt) black, which increases the surface area but has little effect on the physical extent of the electrodes. However, because of the low durability of Pt black plating, this method has not been popular for chronic use. Sonicoplating (i.e. electroplating under ultrasonic agitation) has been shown to improve the durability of Pt black on the base metals of macro-electrodes used for cyclic voltammetry. This method has not previously been characterized for MEAs used in chronic neural implants. We show here that sonicoplating can lower the impedances of microwire multi-electrode arrays (MMEA) by an order of magnitude or more (depending on the time and voltage of electroplating), with better durability compared to pulsed plating or traditional DC methods. We also show the improved stimulation and recording performance that can be achieved in an in vivo implantation study with the sonicoplated low-impedance MMEAs, compared to high-impedance unplated electrodes.