Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Republic of Korea.
Department of Medical Assistant Robot, Korea Institute of Machinery and Materials (KIMM), Daegu, Republic of Korea.
J Neural Eng. 2021 Nov 19;18(6). doi: 10.1088/1741-2552/ac3656.
. Neural interfaces are an essential tool to enable the human body to directly communicate with machines such as computers or prosthetic robotic arms. Since invasive electrodes can be located closer to target neurons, they have advantages such as precision in stimulation and high signal-to-noise ratio (SNR) in recording, while they often exhibit unstable performance in long-termimplantation because of the tissue damage caused by the electrodes insertion. In the present study, we investigated the electrical functionality of flexible penetrating microelectrode arrays (FPMAs) up to 3 months inconditions.. Theexperiment was performed by implanting FPMAs in five rats. Theimpedance as well as the action potential (AP) amplitude and SNR were analyzed over weeks. Additionally, APs were tracked over time to investigate the possibility of single neuron recording.. It was observed that the FPMAs exhibited dramatic increases in impedance for the first 4 weeks after implantation, accompanied by decreases in AP amplitude. However, the increase/decrease in AP amplitude was always accompanied by the increase/decrease in background noise, resulting in quite consistently maintained SNRs. After 4 weeks of implantation, we observed two distinctive issues regarding long-term implantation, each caused by chronic tissue responses or by the delamination of insulation layer. The results demonstrate that the FPMAs successfully recorded neuronal signals up to 12 weeks, with very stably maintained SNRs, reduced by only 16.1% on average compared to the first recordings, although biological tissue reactions or physical degradation of the FPMA were present.. The fabricated FPMAs successfully recorded intracortical signals for 3 months. The SNR was maintained up to 3 months and the chronic function of FPMA was comparable with other silicon based implantable electrodes.
. 神经接口是使人体能够直接与计算机或假肢机械臂等机器进行通信的重要工具。由于侵入性电极可以更接近目标神经元，因此它们具有刺激精度高和记录信噪比（SNR）高等优点，而由于电极插入引起的组织损伤，它们在长期植入时往往表现出不稳定的性能。在本研究中，我们研究了柔性穿透微电极阵列（FPMAs）在条件下长达 3 个月的电功能。实验通过将 FPMAs 植入 5 只大鼠中进行。在数周内分析了阻抗以及动作电位（AP）幅度和 SNR。此外，还跟踪了 AP 随时间的变化，以研究单个神经元记录的可能性。观察到 FPMAs 在植入后的前 4 周内阻抗急剧增加，同时 AP 幅度降低。然而，AP 幅度的增加/减少总是伴随着背景噪声的增加/减少，导致 SNR 相当稳定地保持。植入 4 周后，我们观察到两种与长期植入相关的独特问题，每种问题都是由慢性组织反应或绝缘层分层引起的。结果表明，FPMAs 成功地记录了神经元信号长达 12 周，SNR 非常稳定，与首次记录相比仅平均降低了 16.1%，尽管存在生物组织反应或 FPMA 的物理降解。所制造的 FPMAs 成功地记录了皮质内信号长达 3 个月。SNR 保持了 3 个月，FPMA 的慢性功能与其他基于硅的可植入电极相当。
