具離子電泳功能並可長期植入之神經探針

Abstract

在現代的電生理的研究中，常使用神經探針以記錄腦神經電位。本研究使用微機電系統技術，設計與製造新型神經探針，依據其功能的不同，本研究的神經探針可分為兩種：完全以聚-對二甲苯包覆之神經探針與具有微流道之神經探針。 對長期植入生物體內的微元件而言，生物相容性的考量是不可或缺的一項指標，為了讓以矽為基材的神經探針更適合進行長期植入的實驗，本研究成功以具有高度生物相容性的高分子材料：「聚-對二甲苯」將探針完全包覆，本研究發展創新的微元件全包覆技術，將微元件整體包覆聚-對二甲苯並且可允許特定位置開洞，突破微機電製程技術以往僅能進行微元件單面的包覆處理。 將神經探針整合微流道，使得探針不但可以傳輸微流體以刺激生物組織，還可以觀察組織受刺激前後的神經電位變化。本研究整合二條微流道於一神經探針上，相對於之前文獻上的相關的研究，本研究省去利用外接的注射幫浦驅動微流體，而改以在微流道前後端佈置電極，提供電壓下，可在微流道中產生離子電泳以驅動微流道內帶電之試劑，。 本研究成功量測兩種神經探針的電氣規格。並以完全聚-對二甲苯包覆之神經探針植入大鼠的大腦皮質中進行動物實驗，可記錄到大鼠後腳受機械刺激所誘發之大腦神經訊號。具有微流道之神經探針上經酒精與純水測試後，確定其微流道(長7釐米、寬60微米)中無任何阻塞。

Nowadays, neuroprobes are commonly used in electrophysiological studies. Novel neuroprobes are designed and implemented with Micro-Electro-Mechanical-System technology in this thesis. There are two kinds of neuroprobes designed: one is the completely parylene-coated and the other is that with micro-fluidic channels neuroprobes. Biocompatibility is essential for a device to be implanted in a living organism chronically. In order to make the silicon-based probes serve this purpose, the designed neuroprobes were completely coated with parylene a high polymer biocompatible material. The neuroprobe integrated with micro-fluidic channel can not only deliver agents to stimulate the tissues but also record the evoked neural potentials. For each neuroprobe two micro-fluidic channels were integrated. Electrodes placed at the front and the end of micro-fluidic channel were applied with a voltage that can cause iontophoresis to drive the agents. We have measured the electrical specifications of two neuroprobes. Completely parylene-coated neuroprobe was implanted in the primary sensory cortex of a living rat and mechanical stimuli were applied on the contralateral hind paw. The evoked potentials was recorded successfully. We tested micro-fluidic channel neuroprobe both by alcohol and by water, and demonstrated that the micro-fluidic channels (7mm-long and 60µm-wide) could function correctly.