School of Electrical and Computer Engineering, University of Seoul , Seoul 130-743, South Korea.
Department of Electrical Engineering and Computer Science, University of Wisconsin-Milwaukee , Milwaukee, Wisconsin 53706, United States.
ACS Nano. 2018 Jan 23;12(1):148-157. doi: 10.1021/acsnano.7b04321. Epub 2018 Jan 8.
Electrical stimulation using implantable electrodes is widely used to treat various neuronal disorders such as Parkinson's disease and epilepsy and is a widely used research tool in neuroscience studies. However, to date, devices that help better understand the mechanisms of electrical stimulation in neural tissues have been limited to opaque neural electrodes. Imaging spatiotemporal neural responses to electrical stimulation with minimal artifact could allow for various studies that are impossible with existing opaque electrodes. Here, we demonstrate electrical brain stimulation and simultaneous optical monitoring of the underlying neural tissues using carbon-based, fully transparent graphene electrodes implanted in GCaMP6f mice. Fluorescence imaging of neural activity for varying electrical stimulation parameters was conducted with minimal image artifact through transparent graphene electrodes. In addition, full-field imaging of electrical stimulation verified more efficient neural activation with cathode leading stimulation compared to anode leading stimulation. We have characterized the charge density limitation of capacitive four-layer graphene electrodes as 116.07-174.10 μC/cm based on electrochemical impedance spectroscopy, cyclic voltammetry, failure bench testing, and in vivo testing. This study demonstrates the transparent ability of graphene neural electrodes and provides a method to further increase understanding and potentially improve therapeutic electrical stimulation in the central and peripheral nervous systems.
利用植入式电极进行电刺激被广泛用于治疗各种神经元疾病，如帕金森病和癫痫，并且是神经科学研究中广泛使用的研究工具。然而，迄今为止，有助于更好地理解神经组织中电刺激机制的设备仅限于不透明的神经电极。用最小的伪影对电刺激的时空神经反应进行成像，可以进行各种用现有不透明电极无法进行的研究。在这里，我们使用植入 GCaMP6f 小鼠的基于碳的全透明石墨烯电极展示了电脑刺激和对底层神经组织的同步光学监测。通过透明石墨烯电极进行了不同电刺激参数的神经活动荧光成像，具有最小的图像伪影。此外，全场电刺激成像验证了与阳极引导刺激相比，阴极引导刺激更有效地激活神经。我们通过电化学阻抗谱、循环伏安法、失效台测试和体内测试，将四层电容石墨烯电极的电荷密度限制表征为 116.07-174.10 μC/cm。这项研究展示了石墨烯神经电极的透明能力，并提供了一种进一步增加理解和潜在改善中枢和周围神经系统治疗性电刺激的方法。
