Carbon fiber on polyimide ultra-microelectrodes
Carbon fiber on polyimide ultra-microelectrodes
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DOI：
10.1088/1741-2552/aa8c88
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发表时间：
2018-02-01
影响因子：
4
通讯作者：
Gardner, Timothy J.
中科院分区：
文献类型：
--
作者：
Gillis, Winthrop F.;Lissandrello, Charles A.;Gardner, Timothy J.
目标。大多数神经记录的准备工作随着时间的推移而退化，最终由于插入创伤和组织反应而失败。这些反应的大小被认为与电极的大小(具体地说，横截面积)、电极的相对硬度和组织对材料的耐受程度有关。柔性碳纤维超微电极比传统电极的横截面小得多，组织反应性低，因此可以提高中枢和周围神经系统的神经记录的寿命。先前仅描述了两种碳纤维阵列设计，由于制造工艺或互连策略的限制，每一种都具有有限的沟道密度。在这里，我们描述了一种在柔性聚酰亚胺衬底上组装碳纤维电极的方法，该方法有望促进高密度记录和刺激阵列的构建。接近。单个碳纤维使用对准工具进行对准，该对准工具使用直接激光写入以亚微米分辨率进行3D打印。在碳纤维上沉积铟，然后进行低温微钎焊，为聚酰亚胺互连提供了一种坚固可靠的电连接方法。主要结果。用SNR>；10和>；120分别记录到小的(125微米)周围神经的自发多单位活动和刺激诱发的复合反应。我们还通过电沉积100 nm厚的氧化Ir薄膜改善了小直径碳纤维通常较差的电荷注入能力，使碳纤维阵列既可用于电刺激，也可用于记录。意义重大。我们在制造技术上的创新为碳纤维超微电极阵列的进一步小型化铺平了道路。我们相信，这些进展将是实现从劳动密集型手动组装向更自动化的制造过程转变的关键步骤。
Objective. Most preparations for making neural recordings degrade over time and eventually fail due to insertion trauma and reactive tissue response. The magnitudes of these responses are thought to be related to the electrode size (specifically, the cross-sectional area), the relative stiffness of the electrode, and the degree of tissue tolerance for the material. Flexible carbon fiber ultra-microelectrodes have a much smaller cross-section than traditional electrodes and low tissue reactivity, and thus may enable improved longevity of neural recordings in the central and peripheral nervous systems. Only two carbon fiber array designs have been described previously, each with limited channel densities due to limitations of the fabrication processes or interconnect strategies. Here, we describe a method for assembling carbon fiber electrodes on a flexible polyimide substrate that is expected to facilitate the construction of high-density recording and stimulating arrays. Approach. Individual carbon fibers were aligned using an alignment tool that was 3D-printed with sub-micron resolution using direct laser writing. Indium deposition on the carbon fibers, followed by low-temperature microsoldering, provided a robust and reliable method of electrical connection to the polyimide interconnect. Main results. Spontaneous multiunit activity and stimulation-evoked compound responses with SNR > 10 and > 120, respectively, were recorded from a small (125 mu m) peripheral nerve. We also improved the typically poor charge injection capacity of small diameter carbon fibers by electrodepositing 100 nm-thick iridium oxide films, making the carbon fiber arrays usable for electrical stimulation as well as recording. Significance. Our innovations in fabrication technique pave the way for further miniaturization of carbon fiber ultra-microelectrode arrays. We believe these advances to be key steps to enable a shift from labor intensive, manual assembly to a more automated manufacturing process.