Ultralow Impedance Graphene Microelectrodes with High Optical Transparency for Simultaneous Deep Two-Photon Imaging in Transgenic Mice
Ultralow Impedance Graphene Microelectrodes with High Optical Transparency for Simultaneous Deep Two-Photon Imaging in Transgenic Mice
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DOI：
10.1002/adfm.201800002
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发表时间：
2018-08-01
影响因子：
19
通讯作者：
Kuzum, Duygu
中科院分区：
文献类型：
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作者：
Lu, Yichen;Liu, Xin;Kuzum, Duygu
在过去的几十年里，光学技术取得了重大进展，彻底改变了我们在转基因动物模型中记录和操纵神经活动的能力。与此同时，人类研究主要依赖于皮层电位的电生理记录，这不能从光学记录中推断出来，导致我们对微尺度人群动力学和大脑尺度神经活动的理解之间存在差距。通过实现电学和光学模态的同时集成，透明石墨烯微电极可以缩小这一差距。然而，石墨烯的高阻抗对该技术的广泛应用构成了巨大挑战。在这里，实验证明石墨烯微电极的这种高阻抗从根本上受到量子电容的限制。通过使用铂纳米颗粒创建平行传导路径来克服这种量子电容限制。石墨烯电极阻抗降低了100倍，同时保持了对深度双光子显微镜至关重要的高光学透明度。使用转基因小鼠模型，同时电记录的皮质活动与高保真度被证明，而在不同的皮质深度的透明微电极下方的成像钙信号。多模态分析的Ca2+尖峰和皮层表面电位提供了独特的机会，以弥合我们的理解细胞动力学和大脑规模的神经活动。
The last decades have witnessed substantial progress in optical technologies revolutionizing our ability to record and manipulate neural activity in genetically modified animal models. Meanwhile, human studies mostly rely on electrophysiological recordings of cortical potentials, which cannot be inferred from optical recordings, leading to a gap between our understanding of dynamics of microscale populations and brain-scale neural activity. By enabling concurrent integration of electrical and optical modalities, transparent graphene microelectrodes can close this gap. However, the high impedance of graphene constitutes a big challenge toward the widespread use of this technology. Here, it is experimentally demonstrated that this high impedance of graphene microelectrodes is fundamentally limited by quantum capacitance. This quantum capacitance limit is overcome by creating a parallel conduction path using platinum nanoparticles. A 100 times reduction in graphene electrode impedance is achieved, while maintaining the high optical transparency crucial for deep two-photon microscopy. Using a transgenic mouse model, simultaneous electrical recording of cortical activity with high fidelity is demonstrated while imaging calcium signals at various cortical depths right beneath the transparent microelectrodes. Multimodal analysis of Ca2+ spikes and cortical surface potentials offers unique opportunities to bridge our understanding of cellular dynamics and brain-scale neural activity.