陽極氧化鋁基板製作侷限型表面電漿共振感測器進行表面電漿子耦合效應之研究

Abstract

近幾年，表面電漿共振由於其免標定性、即時量測性以及增強光學訊號的特色，使其具有使用在生醫檢測領域的潛力。但目前遭遇的困難是表面電漿共振的感測器靈敏度不夠大，無法量測低濃度的生物分子。因此為了提升此感測器的靈敏度。我們利用電漿子耦合的原理，調整奈米金屬粒子的大小及間距，藉以研究電漿子耦合對於提升靈敏度的關係。為達成此項目的，本文提出了利用陽極氧化鋁製作表面電漿共振感測器的方法，利用陽極氧化鋁易於控制間距與孔徑大小的特性，製作各種間距/粒徑(G/D)比例不同的結構。而為了有效預測實驗結果，我們先模擬了 36 種不同參數的奈米金粒子，分為週期為 125nm、100nm、75nm、60nm 四組，並觀察其電場與光譜。透過模擬結果，我們成功應證了波峰位置與感測器的奈米金粒子G/D 比例呈現指數遞減的趨勢，且週期最大者(125nm)的組別在相同 G/D 比值中普遍擁有較好的性能表現。並進一步利用此一特性提升剝離式感測器靈敏度，成功量測樣品中濃度在 1.1~30μg/mL 之間的 C 反應蛋白(CRP)。並且，我們提出另一非剝離式的感測器架構，利用，期望可以有效解決陽極氧化鋁製程中，蒸鍍無法應用在大深寬比結構的限制。

The localized surface plasmon resonance (LSPR) sensing technique has recently drawn great attention in biosensing fields due to its label-free, real time and optical-enhanced features. However, the LSPR sensor still suffer from its relatively low sensitivity. To solve this problem, we aim to utilize the plasmonic coupling effect to increase sensitivity of the LSPR sensor by adjusting the period and the diameter of nanoparticles. We utilized anodic aluminum oxide (AAO), which can better control period and diameter and fabricate structures with various gap/diameter (G/D) radios. To predict the experimental result accurately, we simulate 36 structures, which are divided into 4 groups (period=125nm, 100nm, 75nm, 60nm), and observe the electric field and spectrum. Through simulation, we confirm that sensitivity exponentially decay with G/D radio of nanoparticles. Generally, the max period group (114nm) has better Performance at same G/D radio. Finally, we successfully use plasmonic coupling effect to increase the sensitivity of LSPR sensor which is fabricated by lift off AAO, and we detect C-Reactive protein (CRP) with concentration from 1.1 to 30µg/mL. In lift off AAO sensor fabrication, evaporation cannot be applied to the high height/weight radio structure. To overcome this fabrication limitation, we propose another non-lift off AAO fabrication to solve this problem.