This study reports on the development of vertical, partially encapsulated nanoelectrodes for electrically contacting the interior of electrogenic cells with microelectronics. Intracellular electrical stimulation and recording with single cell resolution enables new insights into the electrophysiology of cells embedded in a complex multicellular network, providing detailed understanding of fundamental processes affecting cell to cell communication and thereby paving the way for novel applications including pharmacological studies and other neuromodulation techniques like focused ultrasound and electroceuticals. In order to minimize the influence of the measurement system, an approach based on nano-sized hollow electrodes, achieving an adhesion based intracellular access, is used. The focus of the presented work is on the novel fabrication technology and the characterization of the resulting nanoelectrodes. In CMOS compatible processes, the hollow geometry is achieved using a sacrificial layer technique combining deep reactive ion etching and atomic layer deposition of Ru. For decoupling the extracellular milieu, a partial passivation of the nanoelectrodes by Ta2O5 is realized. The monolithic integration allows an application specific fine-tuning of geometry and placement of the nanoelectrodes. A discrete microelectrode array was designed to electrically and electrochemically characterize the nanoelectrodes. Resistance measurements, cyclic voltammetry and electrochemical impedance spectroscopy show the feasibility of the developed electrodes as an electronic interface to electrochemical fluids. Specifically, an electrode resistance of 2.92 $\text{k}\Omega $ and charge delivery capacitance of $748.13~\frac {\mu \text {C}}{\text {cm}^{2}}$ were observed. Confocal microscopy analyses of neural cells interfaced with the nanoelectrodes indicate an adhesion based intracellular access as well as biostability and biocompatibility. [2020-0224]

中文翻译：

---

垂直、部分封装的纳米电极阵列的单片集成和分析

这项研究报告了垂直的、部分封装的纳米电极的发展，用于将生电细胞内部与微电子进行电接触。单细胞分辨率的细胞内电刺激和记录使人们对嵌入复杂多细胞网络中的细胞的电生理有了新的认识，提供对影响细胞间通讯的基本过程的详细了解，从而为包括药理学研究和其他神经调节技术在内的新应用铺平道路像聚焦超声和电学。为了最大限度地减少测量系统的影响，使用了一种基于纳米尺寸中空电极的方法，实现了基于粘附的细胞内通路。所介绍工作的重点是新颖的制造技术和所得纳米电极的表征。在 CMOS 兼容工艺中，使用结合深度反应离子蚀刻和 Ru 原子层沉积的牺牲层技术来实现中空几何形状。为了解耦细胞外环境，实现了由 Ta2O5 对纳米电极的部分钝化。单片集成允许对纳米电极的几何形状和位置进行应用特定的微调。离散微电极阵列被设计用于电学和电化学表征纳米电极。电阻测量、循环伏安法和电化学阻抗谱表明所开发的电极作为电化学流体的电子界面的可行性。具体来说，观察到 2.92 $\text{k}\Omega $ 的电极电阻和 $748.13~\frac {\mu \text {C}}{\text {cm}^{2}}$ 的电荷传输电容。与纳米电极接口的神经细胞的共聚焦显微镜分析表明基于粘附的细胞内通路以及生物稳定性和生物相容性。[2020-0224]