- 學位論文
一種以奈米碳管電極材料製作之新穎神經探針
Carbon Nanotubes as an Electrode Material for Novel Neural Probes
摘要
傳統的神經探針已被廣泛應用於研究腦神經的電生理功能，然而目前發展的多種傳統微電極探針，仍無法長期可靠地偵測神經細胞活動，及區域性、選擇性地刺激神經組織，其主要歸因於下列缺點: (1)電極尺寸仍過大，易傷害細胞，(2)目前電極多用金屬材質電極，在低頻區段具高阻抗，(3)長期植入後會引發局部發炎或免疫相關反應。為解決上述問題，本研究將利用奈米碳管(carbon nanotubes)當作探針來取代傳統的神經探針。 本論文主要研究一種新穎的三維錐狀奈米碳管探針(cone-shaped 3D carbon nanotube probe)，以運用於神經訊號之記錄。奈米碳管是利用催化化學氣相沉積法(catalytic thermal chemical vapor deposition)合成於矽尖錐上，此三維結構探針和一般二維探針在同樣投影面積相比下，具有較大的奈米碳管表面積，在神經訊號量測上更具有較高的空間解析度。此外本論文也利用水電漿(H2O plasma)和氧電漿(O2 plasma)處理，來修飾奈米碳管的表面特性。及以微波(microwave)處理，來增進奈米碳管和其基板的附著性。由電化學量測結果顯示，經由氧電漿處理過後的奈米碳管具有較低的介面阻抗(~ 64.5 mm-2)和較高的介面電容(~ 2.5 mF cm-2)。本論文更進一步利用經氧電漿處理的奈米碳管探針來偵測螯蝦的神經訊號，結果顯示本研究所研發的經氧電漿處理的奈米碳管探針，具有較佳的量測空間解析度和極佳的電化學特性，對於神經訊號記錄應用具有極大的潛力。
並列摘要
Traditional neural electrodes have been employed widely to investigate the physiological functions of the brain. However, various micro-electrode probes currently developed still cannot reliably detect the activity of the neural cell for a long term, and cannot stimulate the neural tissues regionally and selectively. This is mainly due to that the probe size is still too large, the impedance is too high for metallic electrodes at low frequency region, and the long time implantation will induce tissue inflammation. To resolve above issues, this research is to study carbon nanotubes (CNTs) as an neural electrode material to replace traditional neural electrodes. A novel cone-shaped 3D carbon nanotube (CNT) probe is proposed as an electrode for the applications in neural recording in this work. The electrode consists of CNTs synthesized on the cone-shaped Si (cs-Si) tip by catalytic thermal chemical vapor deposition (CVD). This probe exhibits a larger CNT surface area with the same footprint area and higher spatial resolution of neural recording compared to planar-type CNT electrodes. An approach of improving the CNT characteristics by H2O or O2 plasma treatment to modify the CNT surface will be also presented. In addition, the effect of microwave (MW) treatment to improve the adhesion of carbon nanotubes (CNTs) to a substrate is examined. According to electrochemical characterization, O2 plasma-treated 3D CNT (OT-CNT) probes revealed low impedance per unit area (~ 64.5 mm-2) at 1 kHz and high specific capacitance per unit area (~ 2.5 mF cm-2). Furthermore, the OT-CNT probes were employed to record the neural signals of a crayfish nerve cord. The findings in this work suggest that OT-CNT probes exhibit potential advantages of high spatial resolution and superb electrochemical properties which are suitable for neural recording applications.