Cruttenden Corey E, Taylor Jennifer M, Hu Shan, Zhang Yi, Zhu Xiao-Hong, Chen Wei, Rajamani Rajesh
Department of Mechanical Engineering, University of Minnesota, 111 Church St. SE, Minneapolis, MN.
Department of Biomedical Engineering, University of Minnesota, 312 Church St. SE, Minneapolis, MN.
Biomed Phys Eng Express. 2017;4(1). doi: 10.1088/2057-1976/aa948d. Epub 2017 Nov 27.
Previous animal studies have demonstrated that carbon nanotube (CNT) electrodes provide several advantages of preferential cell growth and better signal-to-noise ratio when interfacing with brain neural tissue. This work explores another advantage of CNT electrodes, namely their MRI compatibility. MRI-compatible neural electrodes that do not produce image artifacts will allow simultaneous co-located functional MRI and neural signal recordings, which will help improve our understanding of the brain.
Prototype CNT electrodes on polyimide substrates are fabricated and tested and in rat brain at 9.4T. To understand the results of the and studies, a simulation model based on numerical computation of the magnetic field around a two-dimensional object in a tissue substrate is developed.
The prototype electrodes are found to introduce negligible image artifacts in structural and functional imaging sequences and . Simulation results confirm that CNT prototype electrodes produce less magnetic field distortion than traditional metallic electrodes due to a combination of both superior material properties and geometry. By using CNT films, image artifacts can be nearly eliminated at magnetic fields of strength up to 9.4T. At the same time, the high surface area of a CNT film provides high charge transfer and enables neural local field potential (LFP) recordings with an equal or better signal-to-noise ratio (SNR) than traditional electrodes.
CNT film electrodes can be used for simultaneous MRI and electrophysiology in animal models to investigate fundamental neuroscience questions and clinically relevant topics such as epilepsy.
先前的动物研究表明，碳纳米管（CNT）电极在与脑神经网络组织连接时具有促进细胞优先生长和更好的信噪比等多个优势。本研究探索了CNT电极的另一个优势，即其磁共振成像（MRI）兼容性。具有MRI兼容性且不产生图像伪影的神经电极将能够同时进行共定位的功能MRI和神经信号记录，这将有助于增进我们对大脑的理解。
在聚酰亚胺基板上制备了CNT电极原型，并在9.4T磁场下于大鼠脑中进行测试。为了理解测试和研究结果，开发了一个基于组织基板中二维物体周围磁场数值计算的模拟模型。
在结构和功能成像序列中，发现该电极原型产生的图像伪影可忽略不计。模拟结果证实，由于材料特性和几何形状均优越，CNT电极原型产生的磁场畸变比传统金属电极小。通过使用CNT薄膜，在高达9.4T的磁场下几乎可以消除图像伪影。同时，CNT薄膜的高表面积提供了高电荷转移能力，并能够进行神经局部场电位（LFP）记录，其信噪比（SNR）与传统电极相当或更好。
CNT薄膜电极可用于动物模型中的同步MRI和电生理学研究，以探讨基础神经科学问题以及癫痫等临床相关课题。
