Shandhi Md Mobashir Hasan, Negi Sandeep
School of Electrical and Computer Engineering. University of Utah, Salt Lake City, UT, USA.
J Microelectromech Syst. 2020 Aug;29(4):522-531. doi: 10.1109/jmems.2020.3004847. Epub 2020 Jul 2.
The Utah Electrode Array (UEA) and its different variants have become a gold standard in penetrating high channel count neural electrode for bi-directional neuroprostheses (simultaneous recording and stimulation). However, despite its usage in numerous applications, it has one major drawback of having only one active site per shaft, which is at the tip of the shaft. In this work, we are demonstrating a next-generation device, the Utah Multisite Electrode Array (UMEA), which is capable of having multiple sites around the shaft and also retaining the site at the tip. The UMEA can have up to 9 sites per shaft (hence can accommodate 900 active sites) while retaining the form factor of the conventional UEA with 100 sites. However, in this work and to show the proof of concept, the UMEA was fabricated with one active site at the tip and two around the shaft at different heights; thus, three active sites per shaft. The UMEA device is fabricated using a 3D shadow mask patterning technology, which is suitable for a batch fabrication process for these out-of-plane structures. The UMEA was characterized by in-vitro tests to showcase the electrochemical properties of the shaft sites for bi-directional neuroprostheses in contrast to the traditional tip sites of the standard UEA. The UMEA not only improves the channel density of conventional UEAs and hence can access a larger population of neurons, but also enhances the recording and stimulation capabilities from different layers of the human cortex without further increasing the risk of neuronal damage.
犹他电极阵列（UEA）及其不同变体已成为用于双向神经假体（同时记录和刺激）的高通道数穿透式神经电极的黄金标准。然而，尽管它在众多应用中得到了使用，但它有一个主要缺点，即每个轴只有一个活性位点，位于轴的尖端。在这项工作中，我们展示了一种下一代设备，即犹他多位点电极阵列（UMEA），它能够在轴周围有多个位点，同时在尖端也保留位点。UMEA每个轴最多可拥有9个位点（因此可容纳900个活性位点），同时保持具有100个位点的传统UEA的外形尺寸。然而，在这项工作中，为了展示概念验证，UMEA制作成在尖端有一个活性位点，在轴周围不同高度有两个活性位点；因此，每个轴有三个活性位点。UMEA设备采用3D荫罩图案化技术制造，该技术适用于这些平面外结构的批量制造工艺。通过体外测试对UMEA进行了表征，以展示与标准UEA的传统尖端位点相比，轴位点用于双向神经假体的电化学特性。UMEA不仅提高了传统UEA的通道密度，从而可以接触到更多的神经元群体，而且还增强了从人类皮质不同层进行记录和刺激的能力，同时不会进一步增加神经元损伤的风险。
