以二氧化錫電極為基礎應用電流/電壓式雙模原理研製葡萄糖及尿酸生物感測器之研究

A Study on the Fabrication of SnO2 Electrode-Based Glucose and Uric Acid Biosensors Using Amperometric/Potentiometric Dual Mode Principles

廖承威(Cheng-Wei Liao)

指導教授 ： 謝瑞香 ； 熊慎幹

中原大學/工學院/生物醫學工程學系/博士(2008年)

https://doi.org/10.6840/cycu200900043

摘要

本論文係以二氧化錫(Tin oxide, SnO2)材料為基礎分別濺鍍於氧化銦錫玻璃(Indium tin oxide glass, ITO glass)及碳電極，藉由二氧化錫/氧化銦錫及二氧化錫/碳電極，分為作為電壓式及電流式生物感測器之基礎電極，以完成電壓式及電流式之葡萄糖及尿酸生物感測器的研製。
電壓式葡萄糖生物感測器於pH 7.5之環境下量測，可達葡萄糖濃度360 mg/dl之偵測極限；研究結果顯示，葡萄糖氧化酵素(Glucose oxidase, GOD)與電子傳遞物(Ferrocenecarboxylic acid, FcA)之最佳化重量比例為1:1。
電壓式尿酸生物感測器之偵測範圍，於pH 7.5之量測環境下為2 mg/dl至7 mg/dl；尿酸酵素、電子傳遞物及過氧化氫催化酵素之最佳化重量比例為4:1:2。
本論文中藉由聚丙烯胺(Polyacrylamide)將葡萄糖氧化酵素與電子傳遞物固定於電極表面，以完成二氧化錫/碳電極電流式葡萄糖生物感測器之備製。當外加電壓設定於300 mV之條件下，二氧化錫/碳電極及碳電流式葡萄糖生物感測器之偵測極限分別為520及240 mg/dl。另當採用聚乙烯醇光聚合物(Poly vinyl alcohols bearing styrylpyridinium groups, PVA-SbQ)作為固定介質時，藉由二氧化錫薄膜修飾後之碳電極作為電流式葡萄糖生物感測器基礎電極時，其外加電壓由452 mV降至236 mV，電流密度由320 μAcm−2提升至508 μAcm−2，且偵測極限增高至葡萄糖濃度600 mg/dl。此外，本論文分別利用掃描式電子顯微鏡(Scanning electron microscopy, SEM)、掃描式原子探針顯微鏡(Scanning probe microscope, SPM)、X射線光電子能譜儀(X-ray photoelectron spectroscopy, XPS) 及半導體參數分析儀，分析二氧化錫薄膜之特性。
最後，本研究亦設計一可適用於電壓式及電流式訊號偵測之雙模電路，藉由一開關元件將此電流式與電壓式生物感測器結合於同一系統，以完成一小尺寸、低成本之電流/電壓式雙模生物感測器。電流式生物感測器具快速偵測之特點，然電壓式生物感測器則有偵測電路簡單及省電之優點；本論文藉雙模電路將電流式與電壓式生物感測器整合於同一系統，以完成電流/電壓式雙模生物感測器之研製，藉此提供使用者多重互補式之使用選擇。

關鍵字

葡萄糖生物感測器 ； 尿酸生物感測器 ； 電子傳遞物 ； 雙模生物感測器 ； 二氧化錫 ； 酸鹼感測器

並列摘要

In this study, a potentiometric base electrode is fabricated on a tin oxide (SnO2) /indium tin oxide (ITO) glass pH sensor by sputtering SnO2 thin film on an ITO glass. Furthermore, a SnO2 thin film is sputtered onto a carbon electrode to develop a SnO2/carbon electrode as an amperometric base electrode. Accordingly, the glucose and uric acid biosensors based on the potentiometric and amperometric base electrodes are realized.
Then, enzymes and electron mediator are coimmobilized on the sensing window of the SnO2/ITO glass pH sensor by covalent bonding method to fabricate glucose and uric acid potentiometric biosensors. The detection limit of the SnO2/ITO potentiometric glucose biosensor is up to a glucose concentration of 360 mg/dl. The experimental result indicates that the optimal weight ratio of glucose oxidase (GOD) to ferrocenecarboxylic acid (FcA) is 1:1. The output signal is associated with the pH of the measurement environment and the optimal pH value is pH 7.5. On the other hand, the SnO2/ITO potentiometric uric acid biosensor responds linearly between 2 mg/dl and 7 mg/dl at pH 7.5, in 20mM of test solution. The optimal weight ratio of uricase, FcA to catalase is 4:1:2.
In this study, polyacrylamide is applied to coimmobilize the enzyme and electron mediator on the base electrode, SnO2/carbon electrode, to develop a SnO2/carbon amperometric glucose biosensor. As the applied potential is set at 300 mV, the detection limits of the SnO2/carbon amperometric glucose biosensor and carbon amperometric glucose biosensor are 520 mg/dl and 240 mg/dl, respectively. For the amperometric glucose biosensor, after the SnO2 thin film is sputtered on the carbon electrode, the applied potential is reduced from 452 mV to 236 mV, the current response is raised from 320 μAcm−2 to 508 μAcm−2 and the detection limit is extended to 600 mg/dl based on the poly vinyl alcohols bearing styrylpyridinium groups (PVA-SbQ) immobilization method. Additionally, to investigate the reasons of reducing applied potential and raising current response after the SnO2 thin film sputtered on the carbon electrode, the SnO2 thin film characteristic is analyzed by scanning electron microscopy (SEM), scanning probe microscope (SPM) and X-ray photoelectron spectroscopy (XPS). Additionally, the Semiconductor Parameter Analyzer and Electrochemical Instrument are applied to analyze the electrical property of the SnO2 thin film sputtered on the carbon electrode.
Finally, a dual mode technique is proposed. The amperometric and potentiometric modes are linked in one system by a 9-pin switch to establish a dual mode biosensor. The homemade dual mode circuit is designed for detecting amperometric and potentiometric signals to realize the small dimension and low cost advantages for portable and home-care purposes. According to the experimental results, the merit for the amperometric glucose biosensor is rapid detection. Conversely, the potentiometric glucose biosensor can be operated under a simple circuit and power consumption saving. Obviously, amperometric and potentiometric glucose biosensors possess their own specific advantages. Consequently, the measurement determined upon the dual mode system will achieve the merits of amperometric and potentiometric methods simultaneously.

並列關鍵字

Uric acid biosensor ； Potentiometric ； Amperometric ； Glucose biosensor ； Dual mode biosensor ； pH sensor ； Tin oxide (SnO2)

參考文獻

[1] G. A. Evtugyn, H. C. Budnikov, and E. B. Nikolskaya, “Sensitivity and selectivity of electrochemical enzyme sensors for inhibitor determination,” Talanta, vol. 46, pp. 465-484, 1998.

[2] P. T. Kissinger, “Biosensors – a perspective,” Biosensors and Bioelectronics, vol. 20, pp. 2512-2516, 2005.

[3] J. D. Newman and A. P. F. Turner, “Home blood glucose biosensors: a commercial perspective,” Biosensors and Bioelectronics, vol. 20, pp. 2435-2453, 2005.

[4] E. Wilkins and P. Atanasov, “Glucose monitoring: state of the art and future possibilities,” Medical Engineering and Physics, vol.18, no.4, pp.273-288, 1996.

[5] H. Patel, X. Li, and H. I. Karan, “Amperometric glucose sensors based on ferrocene containing polymeric electron transfer systems-a preliminary report,” Biosensors and Bioelectronics, vol.18, pp. 1073-1076, 2003.