結合金屬孔陣列與交流電動力快速檢測C反應蛋白之表面電漿子共振與電化學反應

Rapid Detection of C-Reactive Proteins Using Surface Plasmon Resonance and Electrochemistry Combined with Au Nanohole Array and AC-Electrokinetic

馬旭慶(Syu-Cing Ma)

指導教授 ： 黃建璋

國立臺灣大學/電機資訊學院/光電工程學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202202815

摘要

本篇論文介紹了一設計元件，結合了金屬奈米孔陣列與交流電動力，可快速檢測C反應蛋白之表面電漿子共振與電化學反應，本篇分為兩部分:
在第一部分中我們介紹此元件，其結合了金屬奈米孔陣列和交流電動力，奈米孔陣列的設計可以使特定波長的光侷限在金屬表面，可在反射光的頻譜上觀察到特定波段的光強度下降，此為滿足動量方程式的結果，因此現象對周遭折射率的變化相當敏感，可以拿來當作生物感測器。在電化學部分裡用量測表面的阻抗值可量測金屬表面與生物分子的結合，進而觀察到待測物的組成和濃度。交流電動力裝置可透過施加交流電將待測物集中到工作區域，其原因為在正負電極會聚集不同的正負離子，造成液體的導電度不同進而產生流動，交流電動力可在即時檢測(POCT)中達到快速檢測的效果。實驗結果呈現此元件的高靈敏度及快速檢測，在C反應蛋白1 mg/L ~ 1000 mg/L檢測中量測極限可達到30 µg/L，且在過往的研究當中，C反應蛋白需要15分鐘以上才能和適體結合，使用交流電動力裝置可以使時間縮短為60秒，在電化學方面此元件可達到更低的檢測極限，達到8 ng/L，遠低於在人體當中的正常值，顯示此設計與分析非常具有潛力應用於生物感測器中。
第二部分討論了當同時量測光譜訊號及電化學訊號的同時，光譜是否會受到電壓或者頻率上的影響，觀察到光譜不只受到代測物濃度的影響，同時也受到電壓和頻率的影響，原因為在施加電壓或是頻率的同時，溶液中的離子會因吸附作用在金屬表面產生雙電層電容，這些離子吸附會改變金屬表面的離子濃度，導致折射率的不同進而在光譜上看到變化。觀察到施加的電壓越強則觀察到的波長變化越大，而當表面綁定更多的生物分子時，施加相同的電壓差所觀察到的波長變化越小。而在頻率變化上我們觀察到當頻率越高時波長的變化越小，因在低頻時較能吸引離子到金屬表面。此方面的研究探討和得出的結果可以作為未來生物界面科學應用設計，例如基於組合電化學和表面電漿子共振的傳感技術。

關鍵字

表面電漿子共振 ； 電化學阻抗譜 ； 伏安法 ； 生物感測器 ； 交流電動力 ； C反應蛋白 ； 金屬奈米孔陣列

並列摘要

This paper introduces a design element that combines Au nanohole arrays and AC-electrokinetic to rapidly detect surface plasmon resonance and electrochemical reactions of C-reactive protein. This paper is divided into two parts:
In the first part, we introduce this element, which combines Au nanohole arrays and AC-electrokinetic. The design of the nanohole arrays can confine light of a specific wavelength to the metal surface, and the reflection spectrum can be observed in a wavelength deep. The decrease in light intensity is the result of satisfying the wave vector equation, so the phenomenon is quite sensitive to changes in the surrounding refractive index and can be used as a biosensor. In the electrochemical part, the impedance value can be used to measure the binding of the biomolecules to the metal surface, from which the composition and concentration of the analyte can be observed. The AC-electrokinetic device can collect the biomolecules to the working area by applying alternating current. The reason is that negative and positive ions will accumulate in the positive and negative electrodes, resulting in different conductivity of the liquid and make flow. The AC-electrokinetic can be used in point-of-care-testing (POCT), which can achieve the effect of rapid detection. The experimental results show the high sensitivity and rapid detection. The detection limit of C-reactive protein from 1 mg/L to 1000 mg/L can reach 30 µg/L. In previous studies, C-reactive protein required 15 minutes to combine with the aptamer, but AC-electrokinetic device in this paper can shorten the time to 60 seconds. In terms of electrochemistry, this element can reach a lower detection limit in 8 ng/L, which is much lower than the normal value in the human body. It shows that our design and analysis have great potential for application in biosensors.
In the second part, we discussed whether the spectrum is affected by voltage or frequency when we measure the spectrum and the electrochemical at the same time. We observed that the spectrum is not only affected by the concentration of the analyte, but also by the voltage and frequency. When a voltage or frequency is applied, the ions in the solution will generate electric double layer capacitance on the metal surface due to adsorption, and the adsorption of ions will change the ion concentration on the metal surface, resulting in a difference in refractive index. It can be observed that applied voltage increase, wavelength shift increase. While the smaller wavelength shift observed when the same voltage difference is applied when more biomolecules are bound to the surface. In terms of frequency change, we discovered that as frequency increases, the wavelength shift becomes smaller because ions are more attracted to the metal surface at low frequencies. The results explored and derived from this research can be designed for future applications in biointerface science, such as sensing techniques based on combined electrochemistry and surface plasmon resonance.

並列關鍵字

Surface Plasmon Resonance ； Electrochemical Impedance Spectroscopy ； Voltammetry ； Biosensors ； AC-electrokinetic ； C-Reactive Protein ； Au nanohole arrays

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