PEDOT-CNT-Coated Low-Impedance, Ultra-Flexible, and Brain-Conformable Micro-ECoG Arrays
PEDOT-CNT-Coated Low-Impedance, Ultra-Flexible, and Brain-Conformable Micro-ECoG Arrays
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DOI：
10.1109/tnsre.2014.2342880
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发表时间：
2015-05-01
影响因子：
4.9
通讯作者：
Ricci, Davide
中科院分区：
文献类型：
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作者：
Castagnola, Elisa;Maiolo, Luca;Ricci, Davide
皮质电图（ECoG）正在成为临床应用的常用工具，例如为癫痫手术或定位肿瘤边界的患者做准备，因为它成功地平衡了侵入性和信息质量。临床ECoG阵列使用毫米级电极和厘米级间距，无法精确映射神经活动。更高分辨率的电极对于当前的临床应用都是感兴趣的，提供了对更精确的神经活动定位和新颖应用的访问，例如神经修复术，其中当前的信息密度和空间分辨率不足以适当地解码用于慢性脑机接口的信号。开发这样的电极并不简单，因为它们的小接触面积增加了电极阻抗，这严重影响了信噪比，并且将这样的电极粘附到大脑表面变得至关重要。最直接的方法需要增加与柔性基板的阵列一致性，同时使用具有上级电化学性质的材料来改善电极性能。在本文中，我们提出了一种超灵活和顺应性的聚酰亚胺为基础的微型ECoG阵列的亚毫米记录站点电化学涂覆高表面积导电聚合物-碳纳米管复合材料，以提高他们的脑电耦合能力。我们的特点是我们的设备电化学和记录从大鼠体感皮层在体内。涂层和未涂层电极的性能进行了直接比较，同时记录相同的神经元活动在多须偏转刺激。最后，我们评估了电极尺寸对体感诱发电位提取的影响，发现与正常的高阻抗微电极相比，我们的低阻抗微电极的记录能力在将其尺寸从0.2 mm减小到0.1 mm时有所改善。
Electrocorticography (ECoG) is becoming a common tool for clinical applications, such as preparing patients for epilepsy surgery or localizing tumor boundaries, as it successfully balances invasiveness and information quality. Clinical ECoG arrays use millimeter-scale electrodes and centimeter-scale pitch and cannot precisely map neural activity. Higher-resolution electrodes are of interest for both current clinical applications, providing access to more precise neural activity localization and novel applications, such as neural prosthetics, where current information density and spatial resolution is insufficient to suitably decode signals for a chronic brain-machine interface. Developing such electrodes is not trivial because their small contact area increases the electrode impedance, which seriously affects the signal-to-noise ratio, and adhering such an electrode to the brain surface becomes critical. The most straightforward approach requires increasing the array conformability with flexible substrates while improving the electrode performance using materials with superior electrochemical properties. In this paper, we propose an ultra-flexible and conformable polyimide-based micro-ECoG array of submillimeter recording sites electrochemically coated with high surface area conductive polymer-carbon nanotube composites to improve their brain-electrical coupling capabilities. We characterized our devices both electrochemically and by recording from rat somatosensory cortex in vivo. The performance of the coated and uncoated electrodes was directly compared by simultaneously recording the same neuronal activity during multiwhisker deflection stimulation. Finally, we assessed the effect of electrode size on the extraction of somatosensory evoked potentials and found that in contrast to the normal high-impedance microelectrodes, the recording capabilities of our low-impedance microelectrodes improved upon reducing their size from 0.2 to 0.1 mm.