立體光學透鏡設計用於提升微流道系統中的螢光光譜偵測

Abstract

微流道系統應用在許多領域，如 DNA 和 RNA 蛋白質， 高輸送量病毒篩查和環境測試的需要。由於在微流道樣品皆屬微量，誘發的螢光可能微弱。因此，大多數的微流道系統部署許多光學元件或光譜設備來提高螢光檢測效率，而導致整體系統體積笨重。光譜分析法應用於科學領域中基本的分析工具。近幾年來，螢光測量使用微型的光譜儀與許多透鏡陣列來提高測量的效率。然而，這些技術遇到高複雜度分析與儀器體積及昂貴光學元件成本的共同問題。在本篇論文的研究中，利用聚二甲基矽氧烷材料來製作立體光學透鏡，此立體透鏡被合併使用在一具有多波長照明的微流體光譜系統，目的為增強低濃度樣品所產生的螢光光譜偵測。結果確認了立體透鏡的聚焦最佳效能在雷射入射角度為15o，也增強了樣品激發及螢光收集的敏感度，並且在收集螢光信號的總量上提升幅度達到210%的倍率放大。這也使得Rhodamine6G 和Pacific Orange兩種染劑的螢光信號檢測極限降至0.1 μg/ml。

Microfluidic systems have been required in many fields, such like analysis of DNA and RNA protein, high throughput virus screening ,and environment testing. Because of the tiny amount of sample in the microfluidics, the induced fluorescence can be weak. Therefore, most of microfluidic systems deploy multiple optical components or spectroscopy equipment to enhance the efficiency of fluorescence detection, causing the system to be bulky. Spectroscopy is a fundamental analytical tool utilized throughout all of the sciences. In recent years, the fluorescence measurements using a miniaturized spectrometers with many lens array to enhance the efficiency of measurement. However, these strategies encounter common issues of complex analyzer volume and expensive optics costs. In this paper, a stereoscopic lens (SL) made of polydimethylsiloxane (PDMS) incorporated in a multi-wavelength-illuminated spectro-microfluidic system is designed, fabricated and characterized for the enhancement of the fluorescence spectral detection with low concentration specimens. Our results confirmed SL’s optimal capabilities of laser beam focusing at incident angle of 15o for sample excitation and fluorescence collection with much enhanced fluorescent sensitivity, and demonstrated an overall increment in efficiency of photon collection as high as 210% of that without implementation of the lens, which allows detection limit down as low as 0.01 μg/ml for both Rhodamine 6G and Pacific Orange.