微電化學電極陣列感測平台於血糖與膽固醇量測之研發

Abstract

根據國際糖尿病協會的統計，在2001年35歲以上的糖尿病患中約有五百萬人同時亦罹患有心血管疾病，糖尿病患者比起一般人有較高的風險引起心臟病及心肌梗塞等心血管疾病的問題，而此兩種疾病的其中兩個重要的生理指標分別是血液中的血糖值及膽固醇值，因此即時監控兩種生理參數有著臨床上的重要的意義。 隨著微機電製程技術的進步，能發展出效能更好體積較小之生化感測器，因此以自行發展之電化學感測平台，發展多酵素之電化學感測器，用以即時檢測血糖及膽固醇值之功能。可感測血糖的靈敏度達1mM，線性範圍為1mM~20mM，膽固醇靈敏度達2mM，線性範圍為2~10mM，以符合臨床上的需求。為了得到較佳的反應線性度，在電極的表面改質上使用比咯高分子以循環伏安法，用電聚合的原理形成均勻孔隙之導電性高分子薄膜，以固定酵素及降低電極的介面阻抗並探討出較佳的掃描速率為30mV/Sec並分析循環次數與介面阻抗間的關係。為微小化感測系統，以TSMC 2P4M 0.35μm CMOS半導體製程，設計以安培法為基礎之轉阻前端放大電路，含Pad面積僅700μm*700μm可降低感測系統的體積節省功率的消耗小於3.34mW，用以驅動及讀取微電極所產生之氧化電流訊號，以定量溶液中的血糖及膽固醇值，再以LabVIEW撰寫信號的擷取與分析介面，可方便行動式平台的資訊轉移。

According to IDF the statistic (International Diabetes Federation) in 2001, 5 million persons aged 35 years and older with diabetes reported being diagnosed with a cardiovascular disease condition. The people have higher risks in heart attacks and strokes. The blood glucose and cholesterol levels in blood are most important biochemical indicator in human blood of the diabetes and cardiovascular disease. Using the MEMS technology, we can develop biosensor with higher performance and smaller size. In this paper, we design the micro electrochemical electrode array which can be used as multi-enzyme electrochemical biosensor. The sensing range for glucose and cholesterol are 1mM~20mM and 2mM~10mM respectively , it is suitable to clinical application. In order to improve the linearity of the sensor, we use the Cycle Voltametry(CV) to immobilize the enzyme on electrode surface and reduce interface impedance by polypyrrole thin film. We have found the best scan rate of CV is 30mV/Sec. For miniaturization of sensing system, we design a preamplifier by TSMC 2P4M CMOS 0.35μm semiconductor process. It can reduce power consumption to less than 3.34mW for driving the micro electrochemical sensor array. We have designed the LabVIEW program for data analysis and mobile platform.