- 學位論文
微流體振盪器研發與生物螢光法檢測
Design of Microfluidic Oscillators and Diagnosis with Fluorescence Methods
摘要
本文主旨在研發微流體振盪器，目標是埋入微全分析系統中作為微流量感測元件或是微流體混合反應器。首先以流場可視化實驗法觀測並歸納流場結構，包括主噴流、回饋流與渦流區，其中渦流區又可分為主渦流、次渦流與小渦流，深入了解流場形態後得知主渦流與次渦流的輪替頻率等於主噴流的振盪頻率，小渦流在回饋流道入口形成閥門效應，時序性調控回饋流的物理量，並且小渦流閥門效應是主噴流擺盪之啟動機制與穩定振盪機制的中繼點。振盪器的幾何變數研究是透過實驗量測壓力擾動頻譜，進行傅利葉轉換，經統計振盪頻率與範圍後，歸納接觸壁面擴張角應為20-30度之間，分流器為銳角並為80-90度之間，接觸壁面形狀應為階梯型，原因是階梯型結構可調控主渦流的尺度與位置，有利於主噴流擺盪與小渦流閥門效應發生，有效縮短不穩定振盪的時間，提昇振盪頻譜的訊雜比，增廣工作範圍，但不可避免有較高的壓損。 經由巨觀流體力學實驗的累積，本研究已能掌控流體振盪器的設計概念，後續研發出一型展新的微流體振盪器作為微流量計或微反應器使用，利用微機電技術SU-8光阻黃光微影和聚二甲基矽氧烷翻製成型再接合的製程實現小量生產，實驗以微觀流場分析與雷射共軛焦技術進行，結果顯示微流體振盪器的流量感測範圍廣泛，工作範圍在雷諾數等於1-100之間，除了可整合至微全析系統中，更可朝於體內即時偵測或體內自動投藥裝置等構想發展。微流體擺盪現象在本文中進一步地被利用於增益流體混合，生物螢光法檢測流體經由振盪過程提高的混合反應效能，利用螢光共振現象(fluorescent resonance energy transfer, FRET)切入微觀混合指標的研究，驗証微流體振盪器以單一元件造成的流體擺盪運動，可提昇流體反應速率到逹80 %以上。 本文研發的微流體振盪器，經實驗與模擬分析、微機電製程和生物螢光法檢測，証實其工作範圍廣泛，並且可藉由主動式的流體擺動，大幅度提昇反應效益，有貢獻於流量感測與微混合等研究領域，研究過程中應用之研究方法-螢光共振法，也有助於微流體工程的研究。
並列摘要
To measure a micro flow rate and to accelerate the reaction between proteins by an unbalanced impingement of feedback flow, we have proposed and verified the design of a self-flapping microfluidic oscillator. Three specific features – the large aspect ratio of the micro-nozzle, the structure of the sudden-expansion inlet and the asymmetric feedback channels – are developed to induce stable oscillation. The large aspect ratio of the micro-nozzle diminishes the influence of viscous force, and the inlet structure triggers flow instability. The conjunction of both factors promotes the occurrence of the Coanda effect, and initiates oscillation. The asymmetric feedback channels produce an unbalanced impingement of the inlet flow, thus reinforcing the initial oscillation to become stably periodic. Beyond the function of a micro flowmeter, the oscillatory characteristics are applicable to accelerate the biochemical reaction between two fluorescent proteins, B-phycoerythrin (BPE) and an Allophycocyanin alpha subunit (ApcA). With fluorescence induced with a laser, we detected the proteins at a specific wavelength to define the region of interaction caused by the oscillatory motions, which clearly enhances the rate of reaction of these fluids. To focus on the reaction phenomenon of twin fluids, we demonstrated biotin-streptavidin binding that was detected via a fluorescence-resonance-energy-transfer (FRET) pair of fluorescent proteins. The FRET signal demonstrated conclusively that that biochemical reaction was promoted through the oscillatory function.