开源工具包：用于神经记录的台式碳纤维微电极阵列
1Department of Biomedical Engineering,University of Michigan, Ann Arbor, 2Department of Mechanical Engineering,University of Michigan, Ann Arbor, 3Department of Mechanical Engineering,University of Massachusetts Lowell, 4Department of Electrical Engineering and Computer Science,University of Michigan, Ann Arbor, 5Neuroscience Graduate Program,University of Michigan, Ann Arbor, 6Robotics Graduate Program,University of Michigan, Ann Arbor
Summary
在这里，我们描述了用于记录神经和大脑 体内 的可定制碳纤维电极阵列的制造方法。
Abstract
传统的周围神经探头主要在洁净室中制造，需要使用多种昂贵且高度专业化的工具。本文介绍了一种碳纤维神经电极阵列的洁净室”轻”制造工艺，经验不足的洁净室用户可以快速学习。这种碳纤维电极阵列制造工艺只需要一个洁净室工具，一台Parylene C沉积机，可以快速学习或以边际成本外包给商业加工设施。该制造工艺还包括手工填充印刷电路板，绝缘和尖端优化。
这里探讨的三种不同的烙铁头优化（Nd：YAG激光器、喷灯和紫外激光器）产生了一系列尖端几何形状和1 kHz阻抗，喷灯光纤产生了最低的阻抗。虽然先前的实验已经证明了激光和喷灯电极的功效，但本文还表明，紫外激光切割光纤可以在 体内记录神经信号。现有的碳纤维阵列要么没有单独的电极，而有利于束，要么需要洁净室制造的填充和绝缘导轨。建议的阵列仅使用可在台式设备上用于光纤群体的工具。这种碳纤维电极阵列制造工艺允许以比市售探头更低的价格快速定制体阵列制造。
Introduction
许多神经科学研究依赖于使用电生理学（ePhys）记录神经信号。这些神经信号对于理解神经网络和新型医学治疗（如脑机和周围神经接口）的功能至关重要1，2，3，4，5，6。围绕周围神经的研究需要定制或市售的神经记录电极。神经记录电极 – 具有微米级尺寸和易碎材料的独特工具和 – 需要一套专门的技能和设备来制造。已经为特定的最终用途开发了各种专用探头;然而，这意味着实验必须围绕当前可用的商业探针进行设计，或者实验室必须投资开发专用探针，这是一个漫长的过程。由于周围神经研究种类繁多，因此对多功能ePhys探针的需求很高4，7，8。理想的 ePhys 探头应具有小型记录站点、低阻抗9 和财务上切合实际的价格点，以便在系统中实施3。
目前的商业电极往往是位于神经外的神经外或袖带电极（神经袖带10，MicroProbes神经袖带电极11），其位于神经外，或囊内，穿透神经并位于感兴趣的分册内。然而，当袖带电极离纤维更远时，它们会从附近的肌肉和其他可能不是目标的束中拾取更多的噪音。这些探针还倾向于收缩神经，这可能导致生物污染 – 神经胶质细胞和疤痕组织的积聚 – 在电极界面处，而组织愈合。囊内电极（如 LIFE12、TIME13 和 Utah Arrays14）增加了分形选择性的优势，并具有良好的信噪比，这对于区分机器接口的信号非常重要。然而，这些探针确实存在生物相容性问题，神经会随着时间的推移而变形3，15，16。当以商业方式购买时，这两种探头都具有静态设计，没有特定于实验的定制选项，并且对于较新的实验室来说成本很高。
为了应对其他探针带来的高成本和生物相容性问题，碳纤维电极可以为神经科学实验室提供一条无需专用设备即可构建自己的探针的途径。碳纤维是一种替代记录材料，外形小巧，可以低损伤插入。碳纤维具有更好的生物相容性，并且比硅的疤痕反应要低得多17，18，19 ，而无需密集的洁净室处理5，13，14。碳纤维具有柔韧性、耐用性，易于与其他生物材料集成19，并且可以穿透和记录神经7，20。尽管碳纤维具有许多优点，但许多实验室发现手动制造这些阵列非常艰巨。一些group21 将碳纤维组合成束，共同产生更大的（约200μm）直径;然而，据我们所知，这些束尚未在神经中得到验证。其他人已经制造了个性化的碳纤维电极阵列，尽管他们的方法需要洁净室制造的碳纤维导轨22，23，24 和设备来填充其阵列17，23，24。为了解决这个问题，我们提出了一种制造碳纤维阵列的方法，该阵列可以在实验室台面上进行，允许即兴修改。由此产生的阵列保持个性化电极头，无需专门的光纤填充工具。此外，还提供了多种几何形状，以满足研究实验的需求。本文以先前的工作为基础8，17，22，25，提供了详细的方法，以最少的洁净室培训时间手动构建和修改多种样式的阵列。
Protocol
所有动物程序均由密歇根大学机构动物护理和使用委员会批准。 1. 选择碳纤维阵列 从 图1所示的三种设计之一中选择印刷电路板（PCB）。注意：对于此协议，Flex 阵列将是重点。 请参阅 Chestek Lab 网站 （https://chestekresearch.engin.umich.edu） 上的 PCB 设计，免费，可随时寄往 PCB 印刷厂订购印刷。 有关每个板的连接器及其?…
Representative Results
提示验证：扫描电镜图像先前的工作20 表明，剪刀切割导致不可靠的阻抗，因为Parylene C在记录站点上折叠。剪刀式切割在这里仅用于在使用额外的精加工方法进行加工之前将纤维切割到所需的长度。使用吸头的扫描电镜图像来确定暴露的碳长度和吸头几何形状（图8）。 Scissor和Nd：YAG激光切割光纤之前已经过审查<sup clas…
Discussion
材料替代
虽然所有使用的材料都在 材料表中进行了总结，但很少有材料需要来自特定的供应商。Flex 阵列板必须来自列出的供应商，因为他们是唯一可以打印柔性板的公司。Flex 阵列连接器也必须从列出的供应商处订购，因为它是专有连接器。强烈建议将Parylene C作为纤维的绝缘材料，因为它在室温下以可靠的方式提供保形涂层，然后可以承受 体内 环境。聚酰亚…
Divulgations
The authors have nothing to disclose.
Acknowledgements
这项工作得到了美国国家神经疾病和中风研究所（UF1NS107659和UF1NS115817）和美国国家科学基金会（1707316）的财政支持。作者感谢密歇根大学工程学院的财政支持以及密歇根材料表征中心和范弗拉克本科实验室的技术支持。作者感谢Khalil Najafi博士使用他的Nd：YAG激光器和Lurie纳米制造设施使用他们的Parylene C沉积机。我们还要感谢特种涂料系统公司（印第安纳州印第安纳波利斯）在商业涂料比较研究中的帮助。
Materials
| 3 prong clams | 05-769-6Q | Fisher | Qty: 2 Unit Cost (USD): 20 |
| 3,4-ethylenedioxythiophene (25 g) (PEDOT) |
96618 | Sigma-Aldrich | Qty: 1 Unit Cost (USD): 102 |
| 353ND-T Epoxy (8oz)++ (ZIF and Wide Board Only) |
353ND-T/8OZ | Epoxy Technology | Qty: 1 Unit Cost (USD): 48 |
| Ag/AgCl (3M NaCl) Reference Electrode (pack of 3) | 50-854-570 | Fisher | Qty: 1 Unit Cost (USD): 100 |
| Autolab | PGSTAT12 | Metrohm | |
| Blowtorch | 1WG61 | Grainger | Qty: 1 Unit Cost (USD): 36 |
| Carbon Fibers | T-650/35 3K | Cytec Thornel | Qty: 1 Unit Cost (USD): n/a |
| Carbon tape | NC1784521 | Fisher | Qty: 1 Unit Cost (USD): 27 |
| Cotton Tipped Applicator | WOD1002 | MediChoice | Qty: 1 Unit Cost (USD): 0.57 |
| Delayed Set Epoxy++ | 1FBG8 | Grainger | Qty: 1 Unit Cost (USD): 3 |
| DI Water | n/a | n/a | Qty: n/a Unit Cost (USD): n/a |
| Dumont Tweezers #5 | 50-822-409 | Fisher | Qty: 1 Unit Cost (USD): 73 |
| Flex Array** | n/a | MicroConnex | Qty: 1 Unit Cost (USD): 68 |
| Flux | SMD291ST8CC | DigiKey | Qty: 1 Unit Cost (USD): 13 |
| Glass Capillaries (pack of 350) | 50-821-986 | Fisher | Qty: 1 Unit Cost (USD): 60 |
| Glass Dish | n/a | n/a | Qty: 1 Unit Cost (USD): n/a |
| Hirose Connector (ZIF Only) |
H3859CT-ND | DigiKey | Qty: 2 Unit Cost (USD): 2 |
| Light-resistant Glass Bottle | n/a | Fisher | Qty: 1 Unit Cost (USD): n/a |
| Micropipette Heating Filiment | FB315B | Sutter Instrument Co | Qty: 1 Unit Cost (USD): n/a |
| Micropipette Puller | P-97 | Sutter Instrument Co | Qty: 1 Unit Cost (USD): n/a |
| Nitrile Gloves (pack of 200) | 19-041-171C | Fisher | Qty: 1 Unit Cost (USD): 47 |
| Offline Sorter software | n/a | Plexon | Qty: 1 Unit Cost (USD): n/a |
| Omnetics Connector* (Flex Array Only) |
A79025-001 | Omnetics Inc | Qty: 1 Unit Cost (USD): 35 |
| Omnetics Connector* (Flex Array Only) |
A79024-001 | Omnetics Inc | Qty: 1 Unit Cost (USD): 35 |
| Omnetics to ZIF connector | ZCA-OMN16 | Tucker-Davis Technologies | Qty: 1 Unit Cost (USD): n/a |
| Pin Terminal Connector (Wide Board Only) |
ED11523-ND | DigiKey | Qty: 16 Unit Cost (USD): 10 |
| Probe storage box | G2085 | Melmat | Qty: 1 Unit Cost (USD): 2 |
| Razor Blade | 4A807 | Grainger | Qty: 1 Unit Cost (USD): 2 |
| SEM post | 16327 | lnf | Qty: 1 Unit Cost (USD): 3 |
| Silver Epoxy (1oz)++ | H20E/1OZ | Epoxy Technology | Qty: 1 Unit Cost (USD): 125 |
| Silver GND REF wires | 50-822-122 | Fisher | Qty: 1 Unit Cost (USD): 423.2 |
| Sodium p-toulenesulphonate(pTS)- 100g | 152536 | Sigma-Aldrich | Qty: 1 Unit Cost (USD): 59 |
| Solder | 24-6337-9703 | DigiKey | Qty: 1 Unit Cost (USD): 60 |
| Soldering Iron Tip | T0054449899N-ND | Digikey | Qty: 1 Unit Cost (USD): 13 |
| Soldering Station | WD1002N-ND | Digikey | Qty: 1 Unit Cost (USD): 374 |
| SpotCure-B UV LED Cure System | n/a | FusionNet LLC | Qty: 1 Unit Cost (USD): 895 |
| Stainless steel rod | n/a | n/a | Qty: 1 Unit Cost (USD): n/a |
| Stir Plate | n/a | Fisher | Qty: 1 Unit Cost (USD): n/a |
| Surgical Scissors | 08-953-1B | Fisher | Qty: 1 Unit Cost (USD): 100 |
| TDT Shroud (ZIF Only) |
Z3_ZC16SHRD_RSN | TDT | Qty: 1 Unit Cost (USD): 3.5 |
| Teflon Tweezers | 50-380-043 | Fisher | Qty: 1 Unit Cost (USD): 47 |
| UV & Visible Light Safety Glassees | 92522 | Loctite | Qty: 1 Unit Cost (USD): 45 |
| UV Epoxy (8oz)++ (Flex Array Only) |
OG142-87/8OZ | Epoxy Technology | Qty: 1 Unit Cost (USD): 83 |
| UV Laser | n/a | WER | Qty: 1 Unit Cost (USD): 30 |
| Weigh boat (pack of 500) |
08-732-112 | Fisher | Qty: 1 Unit Cost (USD): 58 |
| Wide Board+ | n/a | Advanced Circuits | Qty: 1 Unit Cost (USD): 3 |
| ZIF Active Headstage | ZC16 | Tucker-Davis Technologies | Qty: 1 Unit Cost (USD): 925 |
| ZIF Passive Headstage | ZC16-P | Tucker-Davis Technologies | Qty: 1 Unit Cost (USD): 625 |
| ZIF* | n/a | Coast to Coast Circuits | Qty: 1 Unit Cost (USD): 9 |
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