隨著糖尿病患者人口日益攀升,糖尿病的控制與預防遂成為一個急需關注的議題。研究證實，糖化血色素濃度，可有效預防或延緩糖尿病併發症的產生，不像血糖值測定會受到運動、飲食等因素的影響，而有相當大的起伏變化。目前量測技術仍受到檢測儀器成本高、操作複雜、不易攜帶等的限制。因此近年來國內外研究，漸漸地進而轉往生物感測器方面去研究。本篇研究主要建立一個結合微流道的糖化血色素電阻抗感測器，使用平板式電極，其作用面積大，電場分布均勻，分析上更為直觀簡單，目的是透過電訊號直接量測電極間的電容變化，得到糖化血色素濃度與阻抗變化的關係。其主要可分為兩部分:以自組性單分子層達到蛋白質固定和阻抗量測。此種電阻抗感測器不須對蛋白質加以標記，也不需要加入試劑，有低成本、設備小、簡單快速以及可攜式的優點。
電性分析時，電極上固定糖化血色素使用短鏈的硫吩硼酸與糖類之間二醇亞硼酸來選擇，為達糖化血色素分析靈敏度，自組性單分子層能夠越薄越好。自組性單分子的浸泡時間對修飾情形的影響，並且利用螢光技術探討在不同酸鹼值和溫度條件下，糖化血色素與硼酸分子間的交互作用。由於蛋白質層固定於電極上之多寡會影響電場通過之情況，故使用等效電路之元件值評估特性，達成電性分析可以偵測濃度之目的。在阻抗量測部分，首先量測不同磷酸緩衝溶液與不同比例之去離子水混合溶液，成功分辨其不同濃度及其對應的等效電路元件值，證明此感測器的可行性。最後，先後通入純磷酸緩衝溶液與糖化血色素溶液，當生物分子吸附在電極表面時會造成阻抗變化，藉由附著前與附著後的比較，成功檢測濃度區間為10~100 ng/μL之糖化血色素，並證明只需使用量測電極與阻抗量測儀即可藉由電容性變化偵測生物分子的可行性。

A long-term marker of glycolic control in diabetes has made glycated hemoglobin (HbA1c) one of the most important diagnostic assays. This study presents a sensor for HbA1c detection based on impedance measurement. In the measurement process, no additional reagent is required. It is label-free, simple, low cost and low sample volume needed. The impedance biosensor is integrated with a microfluidic device by fabricating a very thin polydimethyl-siloxane (PDMS) layer sandwiched between the substrates. A pair of parallel facing electrodes is fabricated to characterize the impedance change and determine the concentration of HbA1c. Self-assembled monolayer (SAM) of thiophene-3-boronic acid (T3BA) is used for modification on the gold electrodes. When HbA1c interacts with boronic acid portion of SAM, a relatively small change in the electrical property of the surface can be resulted from the presence of HbA1c. In the non-faraidic detection with no redox indicator added, the surface-bound HbA1c is detected by utilizing the capacitive property as a sensing signal. It can be seen that HbA1c with concentrations in the range from 10 to 100 ng/μL produces an approximately logarithmic decrease in the amplitude of impedance. The proposed method for the detection of HbA1c has potential for point-of-care diagnostics and can be widely used for various biomolecules.

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