Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA 94720, USA.
IEEE Trans Neural Syst Rehabil Eng. 2011 Jun;19(3):307-16. doi: 10.1109/TNSRE.2011.2109399. Epub 2011 Jan 31.
Cortical neural prostheses require chronically implanted small-area microelectrode arrays that simultaneously record and stimulate neural activity. It is necessary to develop new materials with low interface impedance and large charge transfer capacity for this application and we explore the use of conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) for the same. We subjected PEDOT coated electrodes to voltage cycling between -0.6 and 0.8 V, 24 h continuous biphasic stimulation at 3 mC/cm² and accelerated aging for four weeks. Characterization was performed using cyclic voltammetry, electrochemical impedance spectroscopy, and voltage transient measurements. We found that PEDOT coated electrodes showed a charge injection limit 15 times higher than Platinum Iridium (PtIr) electrodes and electroplated Iridium Oxide (IrOx) electrodes when using constant current stimulation at zero voltage bias. In vivo chronic testing of microelectrode arrays implanted in rat cortex revealed that PEDOT coated electrodes show higher signal-to-noise recordings and superior charge injection compared to PtIr electrodes.
皮质神经假体需要长期植入的小面积微电极阵列，以同时记录和刺激神经活动。为此，有必要开发具有低界面阻抗和大电荷转移能力的新材料，我们探索了使用导电聚合物聚（3,4-乙二氧基噻吩）（PEDOT）来实现这一目标。我们将 PEDOT 涂层电极在 -0.6 到 0.8 V 之间进行电压循环，以 3 mC/cm² 的 24 小时连续双相刺激和为期四周的加速老化。使用循环伏安法、电化学阻抗谱和电压瞬态测量进行了表征。我们发现，在使用零电压偏置的恒流刺激时，PEDOT 涂层电极的电荷注入极限比铂铱（PtIr）电极和电镀氧化铱（IrOx）电极高 15 倍。在大鼠皮质中植入微电极阵列的体内慢性测试表明，与 PtIr 电极相比，PEDOT 涂层电极具有更高的信噪比记录和更高的电荷注入能力。
