Wang Kevin, Liu Chung-Chiun, Durand Dominique M
Department of Biomedical Engineering and the Neural Engineering Center, Case Western Reserve University, Cleveland, OH 44106, USA.
IEEE Trans Biomed Eng. 2009 Jan;56(1):6-14. doi: 10.1109/TBME.2008.926691.
Current electrode designs require flexible substrates that absorb little moisture and provide large charge injection capability. Sputtered iridium oxide films have superior charge injection capabilities versus noble metals and can adhere to various substrates. Liquid crystal polymers (LCPs) have very little water absorption compared to other flexible substrates. Therefore, the combination of sputtered iridium oxide film on LCP substrate was studied using 50 Hz, 100 micros duration, and 10 mA biphasic current waveforms for 700 h at 67 degrees C in bicarbonate buffer saline. Scanning electron micrograph analysis showed no delamination and approximately 1% of electrode material was lost to the bicarbonate buffer. The charge injection limit and the cathodic charge storage capacity within the water window were 4.6 +/- 1.0 and 31.5 +/-6.6 mC/cm2, respectively. Additional electrochemical analysis revealed significant charge imbalance attributed to oxygen reduction within the water window. These results, along with the flexible, chemically inert, and biocompatible substrate, indicate that sputtered iridium oxide films on LCP could become the method of choice for flexible substrate nerve electrodes.
当前的电极设计需要吸水性小且具备大电荷注入能力的柔性基板。与贵金属相比，溅射氧化铱薄膜具有卓越的电荷注入能力，并且能够附着于各种基板上。与其他柔性基板相比，液晶聚合物（LCP）的吸水性非常小。因此，研究了在LCP基板上溅射氧化铱薄膜的组合，在碳酸氢盐缓冲盐水中于67摄氏度下使用50赫兹、100微秒持续时间和10毫安双相电流波形进行700小时的实验。扫描电子显微镜分析显示没有分层现象，并且约1%的电极材料损失到碳酸氢盐缓冲液中。在水窗口内的电荷注入极限和阴极电荷存储容量分别为4.6±1.0和31.5±6.6毫库仑/平方厘米。额外的电化学分析揭示了在水窗口内由于氧还原导致的显著电荷不平衡。这些结果，连同柔性、化学惰性和生物相容性基板，表明LCP上的溅射氧化铱薄膜可能成为柔性基板神经电极的首选方法。
