Virtual Microchannels for Focusing and Guiding Fluorescent Microbeads Using Dielectrophoretic Force

運用介電泳法聚焦與導引微粒子之虛擬微流道功能

本研究完成一可程式化介電泳晶片，利用晶片內之電極設計可快速的達到聚焦與導引粒子之功能，不需要複雜的流道設計即可完成粒子之操控，此方法稱之為虛擬微流道。然而，欲了解虛擬微流道的導引率之多寡，因此，將以不同流速與導引角度去得到虛擬微流道的最佳設計參數。晶片主要包含二大部分，其一為上層ITO導電玻璃，其二為運用黃光微影製程技術製作底層電極，雙層電極間以OCA光學雙面膠(Optical Clean Adhesive)做為微流道腔體，不僅可以節省光阻之成本，也可省去製作腔體所花費的時間與製程步驟。且底層主要分為二大部份：其一為魚骨頭聚焦電極，以負介電泳力驅動使粒子聚焦；其二為導引電極，利用不同的開關控制不同角度之導引電極，使粒子可依照電極角度與形狀導引至標的區域。根據模擬與實驗結果顯示，粒子可以成功的聚焦與導引至標的區域於本介電泳晶片，且利用不同角度之導引電極 (15°, 30° 與 45°)與螢光粒子可評估粒子導引率之多寡。模擬與實驗結果證實此介電泳晶片具有粒子聚焦與導引雙功能，未來更可將此功能運用於奈米粒子操控與生物醫學檢測之研究。

In this study a programmable dielectrophoretic chip is developed, whose electrode design can be used to rapidly focus and guide microbeads, without the need of a complicated channel design to manipulate the microbeads. The method used for this chip is called ‘virtual microchannel’. The guiding ratio of microbeads depends on two important parameters: the expanding angle of the bottom electrode and the flow rate. Therefore, a series of studies on these two important parameters are conducted to achieve the optimal virtual microchannel design. The structure of a the DEP chip consists of a top electrode made of indium tin oxide (ITO), a flow chamber formed by optically clear adhesive (OCA) tape, and two kinds of bottom electrodes on a glass substrate. The bottom electrodes can be divided into two parts: the first part is for focusing the suspended microbeads by a fish-bone type electrode operated in a negative DEP range; the second part is for switching and guiding these focused microbeads along the electrode surface to the target area, like a flow passing along a virtual channel. The results of the simulation and experiment indicate that microbeads can be aligned along the gap of the fish-bone electrode and be successfully guided into the target area at various angles (15°, 30° and 45°) at a low flow rate. In the future, the virtual microchannel could be further employed for the research of nanoparticle manipulation and biomedical application.