樹狀奈米金與rGO複合材料合成與其電化學感測之研究

Abstract

本研究利用葡萄糖氧化酶(GOx)和血紅蛋白(Hb)兩種酵素分別偵測葡萄糖與過氧化氫，本實驗製作了還原態氧化石墨烯(rGO)與樹狀金電極(GD)的複合材料(GD/rGO)並搭配酵素的薄膜修飾進而製備高靈敏度之生物感測器。應用循環伏安技術和計時電流安培法研究此電極電化學特性。由電化學阻抗(EIS)分析酵素已成功修飾，在X射線光電子能譜(XPS)及拉曼散射光譜的鑑定下證實氧化石墨烯已完成電化學法還原並與樹狀金電極形成複合材料。並利用掃描電子顯微鏡觀察薄膜的表面型態。且根據電化學實驗計算出酵素與修飾薄膜電極表面具快速的電子轉移能力。 從計時安培法結果顯示此GD/rGO/GOx/Nf(Nafion)薄膜對於葡萄糖偵測展現出<3 s的電流響應時間，並具有0.008 mM到7.2 mM寬廣的偵測線性範圍、5 µM最小偵測極限和良好的靈敏度25.23 µAmM-1cm-2。另一方面，GD/rGO/Hb/Nf薄膜偵測過氧化氫也有<5 s的電流響應時間，寬廣的線性範圍0.003 mM到22.7 mM、與極低的偵測極限1 µM和0.623 mAmM-1cm-2的靈敏度。 GOx薄膜修飾電極在含有電子傳導媒介偵測葡萄糖時展現出好的電催化活性，而Hb對於偵測過氧化氫也有卓越的電催化還原能力，並且在製備過程中具備簡易、有效率及無環境污染等優點。

In this thesis, we report the fabrication two highly sensitive hydrogen peroxide and glucose biosensor based on immobilization of glucose oxidase (GOx) and hemoglobin (Hb) on the composites of graphene oxide (rGO) gold dendrites (GD), which are electrodeposited on the GC electrode (GCE). The electrochemical characteristics of the biosensor were studied by cyclic voltammetry (CV) and amperometry. The modified process was characterized by electrochemical impedance spectroscopy (EIS) and cyclic votammetry. The morphologies of modified film were investigated with scanning electron microscopy (SEM) and the element of film was investigated with X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. GOx and Hb were well immobilized onto the GD/rGO film on the rGO and GD composites. The experimental data demonstrate faster electron transfer between enzymes and the modified electrode surface. The results of amperometry response indicates that GD/rGO/GOx/Nf(Nafion) film displayed a fast response of less than 3 s and exhibits low detection limit of 5 µM with wide linear range of 0.008-7.2 mM and good sensitivity of 25.23 µAmM-1cm-2 for glucose detection. On the other hand, the GD/rGO/Hb/Nf film also displays a response of less than 5 s. The proposed hydrogen peroxide biosensor shows a low detection limit of 1 µM with linear range of 0.003-22.7 mM and exhibits excellent sensitivity of 0.623 mAmM-1cm-2. The modified films show high electrocatalytic activity towards glucose in the presence of mediator and exhibit a remarkable electrocatalytic activity for the reduction of hydrogen peroxide. Moreover the fabrication of these two biosensors was simple, efficient and green technique.