以全反射螢光顯微技術結合粒子追蹤測速儀量測高濃度粒子於邊界附近之布朗運動

Abstract

近年來由於科技的進步，結合微機電與生醫技術的生醫感測元件因應而生，而由布朗運動為理論基礎，所建立的新式檢測技術則為本實驗室近年來之目標，此類元件具有操作簡易、製作簡單且價格便宜之優點。於本研究中，針對布朗運動於微流道中運動現象作完整探討，包括布朗運動與邊界距離之討論、邊界表面性質與布朗運動之影響、濃度變化對布朗運動的影響以及環境溶液對於布朗運動之影響，希望可藉由本研究對此新式感測技術進行最佳化設計。本研究進行方式是藉由使用非螢光奈米粒子模擬高濃度情況，再以低濃度螢光粒子置入樣品中以便以粒子追蹤測速儀(PTV)作分析，並且搭配不同環境溶液、表面性質模擬可能遇到之情況。 從實驗中可以看出粒子靠近邊界時受到邊界的影響，布朗運動擴散係數會下降；當樣本中的粒子濃度提高時，直觀來看粒子間的碰撞機率增加導致能量消散更多，造成布朗運動速度下降。此外，表面性質的改變也會使布朗運動擴散係數發生變化，在未來可將此結果應用於建立在布朗運動理論下之新式生醫檢測中，有助於增加其準確度。

In recent years, due to advances in technology, combined with MEMS and biomedical sensing element appeared. Base on the theory of Brownian motion, we established new bio-sensing technology in recent years. Such element has advantages that it’s simple to use, make and low price. In this study, we discuss the phenomena for the Brownian motion in micro-flow channel, including studies on the near-wall Brownian behaviors of particles, high volume fraction effect, how surface modification effects Brownian motion and how environmental solution effects Brownian motion, hope that by this study, we can improve this new sensing technology for optimal design. We use non-fluorescent nanoparticles to simulated high concentrations and use fluorescent particles in low volume fraction to trace the fluid, then use micro-Particle Tracking Velocimetry (PTV) for analysis. Then we change the environmental solutions, do surface modification and mixing different size of particles to simulate the conditions that may be encountered. From the study, we know that the diffusion coefficient of Brownian motion decreases as the particles near the boundary and high volume fraction. Furthermore, surface modification and sample made by different particles size also change particles Brownian behavior, hope that the results of the study can be used in the Brownian motion-based bio-sensing technology and increasing its accuracy.