於介電泳形成之虛擬螺旋微流道內/間進行微液滴混合

Abstract

於實驗室晶片中，由於微小尺度下之流體均以層流的方式流動，試劑間只能經由擴散進行混合，不僅必須花費大量時間等待，亦不符合經濟效益。本論文提出以液體介電泳作為驅動力，首先對於液體介電泳之基本性質做一系列的研究，藉由調整實驗元件之各種參數，完成微閥門與微幫浦之設計。由於在實驗室晶片中兩液滴之接觸面積小，但需擴散之距離長，因此設計了一組電極，將前述設計好之微閥門與微幫浦元件與微混合器整合於同一晶片當中。經介電濕潤傳送使兩顆等體積之液滴相接觸，再以液體介電泳產生細長的液柱，目的是為了有效的縮短液滴之擴散長度。由於此現象發生於介電泳形成之虛擬流道，因此混合完畢時即為一顆均勻的液滴，且可再供進一步的分析。本論文成功地將微幫浦、微閥門及微混合器整合於同一晶片當中，由於製程簡易，因此在應用上具有其方便性。

Mixing of analytes and reagents is a critical step in realizing a lab-on-a-chip. However, due to laminar flow, mixing of liquid is very difficult in micro-scale. In this thesis, we demonstrate fundamental studies of liquid dielectrophoresis (LDEP), and then applied to a micromixer by pumping liquid in/between a dielectrophoresis-formed virtual spiral microchannel. We introduce a spiral-shaped LDEP electrode to increase the contact area at the interface of the merged droplet and decrease the diffusion distance. Two droplets were first created, transported and then merged together by LDEP and electrowetting (EWOD) actuation, by drawing a thin liquid column from the merged droplet, diffusion length can be reduced dramatically. Since this is a dielectrophoresis-formed virtual channel, no channel walls are existed, liquid column can merge together again to form a new droplet for further analyses. Finally, we successfully integrate micropump, microvalve and micromixer on a simple chip without complicated device structure.