植入式神经微电极的设计及神经电信号提取的实验研究

Experimental study of the design of implantable neural microelectrode and the collection of neural electric signal

目的利用神经可塑性原理,应用微制造加工技术设计并制作植入式神经微电极,以探索神经电信号提取与应用的可行性。方法以硅片为电极底板,以铂铱合金丝为导线,用微制造加工技术在硅片上开孔,制作成植入式神经微电极。通过显微外科技术将电极植入大鼠坐骨神经内,经放大电路放大后,用示波器观察所提取之电信号。结果电极实物为一1 mm×1 mm的八角形物体,电极一侧为通孔,内径约300 mm,通孔周围镀有铂金,两侧各有1根导线。植入试验提示,植入后3个月,示波器观察到具有神经电信号特征的静息电位、自发电活动及动作电位。结论自行设计与制作的植入式神经微电极可提取神经电信号,该电极在实用性上明显优于目前常用的纵行神经束内电极,为神经假肢的研究提供了电极基础。

Objective To design and manufacture the implantable neural microelectrode by utilizing the principle of nerve plasticity and the technology of micmfabrication, and to discuss the possibility of collecting and applying the neural electric signals. Methods The implantable neural microelectrode was made from silicon wafer as base and Pt-Ir wire as lead. Holes were drilled on the silicon wafer by utilizing process technology of micmfabrication. The electrode was then implanted microsurgically into the sciatic nerve of the rat. The electric signal was enhanced by the amplifier circuit and collected by oscilloscope. Results The electrode was an octagon with 1.0 mm diameter and a through-hole on the side. The inner diameter of the through-hole with Pt around was about 300 nun. There was a lead on each side of the electrode. The experiment showed that the resting, spontaneous and action potential which had the character of neural electric signal was collected by oscilloscope 3 months after the electrode was implanted. Conclusion The self-designed-and-made implantable neural microelectrode can collect neural electric signal. It is much more practicable than the longitudinal intrafascicular electrode that is mostly used nowadays. It provides the electrode basis for research of the neural limb prosthesis.