Center for Neurotrauma, Neurodegeneration, and Restoration , Corporal Michael J. Crescenz Veterans Affairs Medical Center , Philadelphia , Pennsylvania 19104 , United States.
School of Chemical and Biomolecular Engineering , Cornell University , Ithaca , New York 14853 , United States.
ACS Nano. 2018 Oct 23;12(10):10419-10429. doi: 10.1021/acsnano.8b06014. Epub 2018 Sep 12.
High-resolution neural interfaces are essential tools for studying and modulating neural circuits underlying brain function and disease. Because electrodes are miniaturized to achieve higher spatial resolution and channel count, maintaining low impedance and high signal quality becomes a significant challenge. Nanostructured materials can address this challenge because they combine high electrical conductivity with mechanical flexibility and can interact with biological systems on a molecular scale. Unfortunately, fabricating high-resolution neural interfaces from nanostructured materials is typically expensive and time-consuming and does not scale, which precludes translation beyond the benchtop. Two-dimensional (2D) TiC MXene possesses a combination of remarkably high volumetric capacitance, electrical conductivity, surface functionality, and processability in aqueous dispersions distinct among carbon-based nanomaterials. Here, we present a high-throughput microfabrication process for constructing TiC neuroelectronic devices and demonstrate their superior impedance and in vivo neural recording performance in comparison with standard metal microelectrodes. Specifically, when compared to gold microelectrodes of the same size, TiC electrodes exhibit a 4-fold reduction in interface impedance. Furthermore, intraoperative in vivo recordings from the brains of anesthetized rats at multiple spatial and temporal scales demonstrate that TiC electrodes exhibit lower baseline noise, higher signal-to-noise ratio, and reduced susceptibility to 60 Hz interference than gold electrodes. Finally, in neuronal biocompatibility studies, neurons cultured on TiC are as viable as those in control cultures, and they can adhere, grow axonal processes, and form functional networks. Overall, our results indicate that TiC MXene microelectrodes have the potential to become a powerful platform technology for high-resolution biological interfaces.
高分辨率神经接口是研究和调节大脑功能和疾病相关神经回路的重要工具。由于电极被小型化以实现更高的空间分辨率和通道数，因此保持低阻抗和高信号质量成为一个重大挑战。纳米结构材料可以解决这一挑战，因为它们结合了高导电性、机械柔韧性，并可以在分子尺度上与生物系统相互作用。不幸的是，用纳米结构材料制造高分辨率神经接口通常既昂贵又耗时，而且不具有扩展性，这使得它们无法超越实验室台架。二维（2D）TiC MXene 具有在水溶液中分散体中非常高的体积电容、电导率、表面功能和可加工性的组合，这在碳基纳米材料中是独特的。在这里，我们提出了一种用于构建 TiC 神经电子器件的高通量微制造工艺，并展示了与标准金属微电极相比，其优越的阻抗和体内神经记录性能。具体来说，与相同尺寸的金微电极相比，TiC 电极的界面阻抗降低了 4 倍。此外，在麻醉大鼠大脑的多个时空尺度上进行的术中体内记录表明，TiC 电极的基线噪声更低、信噪比更高，并且对 60 Hz 干扰的敏感性降低，优于金电极。最后，在神经元生物相容性研究中，在 TiC 上培养的神经元与对照培养物中的神经元一样具有活力，并且它们可以附着、生长轴突过程并形成功能性网络。总体而言，我们的结果表明，TiC MXene 微电极有可能成为高分辨率生物接口的强大平台技术。
