本研究主要發展用於周邊神經系統感測與刺激的植入式無線生醫微系統，外部模組主要藉由高效率的Class-E 放大器與振幅移鍵控 (ASK) 調變技術將電源與指令傳送到植入式模組內，擷取的訊號經過取樣及類比數位轉換後並透過負載移鍵控 (LSK) 的方式將此數位訊號傳送到外部模組。透過外部模組的傳輸線圈，外部模組接收的調變訊號會經過解調變及濾波而形成一串列的二進位訊號，最後透過LabVIEW所設計的使用者介面將此擷取的訊號加以顯示。
此雙向無線傳輸首先藉由可接收外部模組傳送來的刺激指令參數 (振幅、工作週期、頻率) 與感測指令參數(接收通道、解析度、取樣頻率)的刺激感測系統來加以驗證，在感測的驗證方面，此系統被用於擷取坐骨神經的神經訊號，之後，此雙向傳輸系統被用於量測環型電極與周邊神經之間的阻抗，在體外模擬的實驗中，利用了我們所設計的阻抗量測系統與商業用的LCR量測儀來對電極表面的阻抗加以量測，實驗結果表示血漿中蛋白質的逐漸沉澱則造成了此表面阻抗的上升，在動物實驗方面，此電極被植入在老鼠背部的皮膚層跟肌肉層之間並用於觀察電極與組織間的阻抗變化，此系統經過生物相容性的包裝後，將可應用在各種的神經擷取與刺激的研究上。

This study aims to develop an implantable wireless biomicrosystem for sensing and stimulating peripheral neural system through inductive link. Power and command were transmitted into implantable module by using high efficient class-E power transmitter and amplitude-shift keying (ASK) modulation technique. The measured signals were sampled and converted into digital signal which can be transmitted outwards through the same radio frequency (RF) link by using the load shift key (LSK) modulation method. From the transceiver coil of external module, the received wave was demodulated and filtered out as the serial binary data which were displayed in a graphics user interface (GUI) designed in LabVIEW.
The bi-directional wireless transmission protocol was first verified in a microstimulation/sensing system which received commands for adjusting the waveform parameters (amplitude, pulse width, frequency) and sensing parameters (channels, resolution and sampling rate) from the external controller. For validation purpose, the electroneurogram of sciatic nerve was recorded. The bi-directional transmission schemes were later applied for measuring the electrode-tissue contact impedance between nerve cuff electrodes and peripheral nerves. For in-vitro test, the increase in impedance was mainly due to the gradual adhesion of protein of blood plasma to microelectrode surface. The impedance measurements of our designed module were comparable to those obtained from the commercial LCR meter. For in-vivo monitoring the electrode-tissue impedance, the microelectrode was implanted between the skin and muscle of Wistar rat’s dorsum. Current system can be extended for various neural sensing and stimulation studies after biocompatible package.

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