具超薄且表面改質介電堆疊結構之改良型電化學生物感測器應用於心肌肌鈣蛋白I檢測

Abstract

心臟疾病在全球一直是主要死因之一，約占全球每年所有死亡數量的33%。而心肌肌鈣蛋白作為評估急性心肌梗塞的重要指標，對預防心肌梗塞相關疾病相當關鍵。然而，目前仍缺乏同時擁有低廉、快速和精準的檢測手段。針對這個需求，本研究中我們開發了基于電荷敏感的微孔陣列結構的電容感測器。這個感測器擁有傳統電容式傳感器的無標記、迅速的檢測特點，同時在結構方面，它以垂直堆疊的電極設計取代了傳統電容式傳感器的平面佈局。這種架構保留了奈米級平面感測器的優勢，並將感測區域的製造複雜性從奈米光刻製程轉移到更具可擴展性的化學氣相沈積製程。此外，通過把感測層從電極表面轉移到電極之間的側壁上，解決了電容式傳感器穩定度和靈敏度相互制衡的問題。

為了探究開發的微孔陣列感測器的特性，我們利用循環伏安法和電化學阻抗譜法，對其在不同的離子濃度中進行測量電雙層電容。在這個過程中，驗證了這個感測器的感測機制。並且在隨後的化學改質步驟裡，發現了矽烷會造成元件明顯的訊號變化。我們利用感測器對電荷的靈敏性，對現有的改質方式進行了優化，並利用螢光法證實，優化後的改質方式可以帶來更好的生物分子改質效率。在改善矽烷的改質策略之後，對帶有不同淨電荷的生物素和鏈黴生物素進行了檢測。結果顯示，對帶電量更多的生物素的檢測極限達到了 120 fM，並且達到了15 fM到150 pM的廣闊的動態范圍。這個結果明顯相較利用其他方法得到的結果更出眾，證明了新型微陣列傳感器對生物分子檢測的優越性。

最後，我們嘗試了多種參數下對心肌鈣蛋白的檢測結果。這些參數包括： 電極間距、培養時間、表征方法、量測溶液的離子濃度。並使用優化過後的參數對在人血清中的心肌鈣蛋白進行了檢測。結果顯示在37攝氏度的環境下讓樣品與微孔陣列感測器進行培養之後，對人血清紅的心肌鈣蛋白可以達到272.32 fg/mL的檢測極限，並且呈現出100 fg/mL到1 ng/mL的動態范圍。這些結果凸顯了新型堆疊式微孔陣列傳感器的先進性，同時，對心肌鈣蛋白的精確、快速的檢測能力也填補了目前檢測方法的空白。我相信這種新型傳感器可以在更廣闊的生醫領域進行運用。

Cardiovascular diseases have consistently ranked among the leading causes of death worldwide, accounting for approximately 33% of all annual global fatalities. Cardiac troponin I (cTnI) serves as a critical biomarker for assessing acute myocardial infarction and plays a key role in the prevention of related conditions. However, current detection methods lack the combined advantages of low cost, rapid response, and high precision. To address this issue, we developed a capacitive sensor based on a charge-sensitive microwell array structure. This sensor retains the label-free and rapid detection characteristics of conventional capacitive sensors, while replacing the traditional planar electrode layout with a vertically stacked design. This architecture preserves the benefits of nanoscale planar sensors and shifts the complexity of sensor fabrication from nanolithography to a more scalable chemical vapor deposition process. Moreover, by relocating the sensing layer from the electrode surface to the sidewalls between electrodes, we resolved the trade-off between stability and sensitivity in capacitive sensing.

To investigate the sensor’s characteristics, cyclic voltammetry and electrochemical impedance spectroscopy were employed to measure the electrical double-layer capacitance under varying ionic concentrations, validating the sensing mechanism. During subsequent chemical modification steps, we observed significant signal changes induced by silane treatment. Leveraging the sensor’s charge sensitivity, we optimized the modification protocol, which was confirmed by fluorescence analysis to enhance biomolecular functionalization efficiency. After optimizing the modification strategy of aminosilanes, we tested biotin and streptavidin with different net charges. The sensor achieved a detection limit of 120 fM for highly charged biotin and demonstrated a broad dynamic range from 15 fM to 150 pM. These results outperform existing methods and highlight the superior performance of the novel micropore array sensor in biomolecular detection. Finally, we evaluated cTnI detection under various parameters, including electrode spacing, incubation time, characterization methods, and ionic concentration of the measurement solution. Using optimized conditions, the sensor achieved a detection limit of 272.32 fg/mL and a dynamic range from 100 fg/mL to 1 ng/mL in human serum at 37 °C.

These findings underscore the advancement of the stacked microwells array sensor and its potential for precise and rapid cTnI detection, filling a critical gap in current diagnostic technologies. We believe this novel sensor holds great promise for broader biomedical applications.