交流電動力應用於石英晶體微天平及微混合器之數值模擬

Abstract

微混合器與石英晶體微天平為生化、生醫領域常見的微流體系統，主要用來進行不同種類的藥品混合與生物分子檢測。在微奈米尺度下，流體為層流狀態，自然擴散為其主要的藥品輸送方式。然而，此種機制需要耗費很長的時間才能達到良好的傳輸效果，在混合與生化反應之使用上效果有限。本研究引入交流電動力，以期能提升混合效能並縮短反應所需之時間。 交流電動力主要的機制有：操縱微小粒子與擾動微流體流場。此外，不同的流體導電度、電壓、交流電訊號頻率、操作尺度等條件能產生不同作用方式的交流電動力，其大致可分為介電泳、電熱效應以及交流電滲三種。 本論文以有限元素分析軟體COMSOL Multiphysics針對電熱效應式石英晶體微天平 (ETE-QCM) 與交流電動式微混合器 (ACEK micromixer) 之實驗架構，進行數值模擬分析，以達到預測實驗走向之效果，並結合相關理論解釋實驗之現象。

Microfluidic devices such as quartz crystal microbalances (QCM) and micromixers are often applied in Biochemistry and Biomedicine to mix different samples and biomolecular detection. At a micro- or nano-scale level, fluid flow is constantly in the state of laminar flow where pure diffusion is its primary mechanism of transporting specimens. However, the transportation through such mechanism consumes considerable time before reaching a point where transportation gets efficient. Thus it poses a restriction on the application of microfluidic devices to both medical mixing and bio-detecting. In this thesis, AC-electrokinetics is adopted to be integrated into microfluidic systems to enhance the mixing efficiency and reduce the detection time. AC-electrokinetics (ACEK) is used to manipulate micro-scale particles and disturb the fluid field in microfluidic systems. On the basis of different conductivities, applied voltages, AC-signal frequencies, and scales etc. AC-electrokinetics can be classified into Dielectrophoresis (DEP), Electrothermal effect (ETE) and AC-electroosmosis (ACEO). In this paper, we conduct the numerical simulations of the experiments on an Electrothermal-QCM chip and an ACEK-micromixer by commercial software “COMSOL Multiphysics”. In the end, the simulated results are compared with the experimental ones done by other students in our research group.