Duncan Jonathan L, Wang Jaime J, Glusauskas Gabriele, Weagraff Gwendolyn R, Gao Yue, Hoeferlin George F, Hunter Allen H, Hess-Dunning Allison, Ereifej Evon S, Capadona Jeffrey R
Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106, USA.
Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, 10701 East Blvd, Cleveland, OH 44106, USA.
Micromachines (Basel). 2024 Feb 17;15(2):286. doi: 10.3390/mi15020286.
(1) Background: Intracortical microelectrodes (IMEs) are an important part of interfacing with the central nervous system (CNS) and recording neural signals. However, recording electrodes have shown a characteristic steady decline in recording performance owing to chronic neuroinflammation. The topography of implanted devices has been explored to mimic the nanoscale three-dimensional architecture of the extracellular matrix. Our previous work used histology to study the implant sites of non-recording probes and showed that a nanoscale topography at the probe surface mitigated the neuroinflammatory response compared to probes with smooth surfaces. Here, we hypothesized that the improvement in the neuroinflammatory response for probes with nanoscale surface topography would extend to improved recording performance. (2) Methods: A novel design modification was implemented on planar silicon-based neural probes by etching nanopatterned grooves (with a 500 nm pitch) into the probe shank. To assess the hypothesis, two groups of rats were implanted with either nanopatterned (n = 6) or smooth control (n = 6) probes, and their recording performance was evaluated over 4 weeks. Postmortem gene expression analysis was performed to compare the neuroinflammatory response from the two groups. (3) Results: Nanopatterned probes demonstrated an increased impedance and noise floor compared to controls. However, the recording performances of the nanopatterned and smooth probes were similar, with active electrode yields for control probes and nanopatterned probes being approximately 50% and 45%, respectively, by 4 weeks post-implantation. Gene expression analysis showed one gene, Sirt1, differentially expressed out of 152 in the panel. (4) Conclusions: this study provides a foundation for investigating novel nanoscale topographies on neural probes.
(1) 背景：皮层内微电极（IMEs）是与中枢神经系统（CNS）进行接口并记录神经信号的重要组成部分。然而，由于慢性神经炎症，记录电极的记录性能呈现出特征性的稳步下降。人们已经探索了植入装置的拓扑结构，以模仿细胞外基质的纳米级三维结构。我们之前的工作利用组织学研究了非记录探针的植入部位，结果表明，与表面光滑的探针相比，探针表面的纳米级拓扑结构减轻了神经炎症反应。在此，我们假设具有纳米级表面拓扑结构的探针在神经炎症反应方面的改善将延伸至记录性能的提高。(2) 方法：通过在平面硅基神经探针的探针柄上蚀刻纳米图案化凹槽（间距为500 nm），对其进行了一种新颖的设计改进。为了评估该假设，将两组大鼠分别植入纳米图案化探针（n = 6）或光滑对照探针（n = 6），并在4周内评估它们的记录性能。进行死后基因表达分析，以比较两组的神经炎症反应。(3) 结果：与对照相比，纳米图案化探针的阻抗和本底噪声增加。然而，纳米图案化探针和光滑探针的记录性能相似，植入后4周时，对照探针和纳米图案化探针的有源电极产量分别约为50%和45%。基因表达分析显示，在该组的152个基因中，有一个基因Sirt1存在差异表达。(4) 结论：本研究为研究神经探针上新型纳米级拓扑结构奠定了基础。
