介電泳應用於紅、白血球分離之研究

Abstract

本論文主要著眼於發展生物晶片中的介電泳晶片運用的原理即為介電泳。利用微流體中負介電泳力與史托克力的平衡，來完成人類全血中的紅、白血球分離及分類晶片。 利用介電泳力牆來阻擋血球的流動是本實驗的關鍵。依據血球中獨特的介電性質，可在不同血球上施予不同的介電泳力，因此每種血球都有自己的臨界阻擋速度。在某一個設計的流速中，白血球順利的被阻擋於平行電極之間隙前，而紅血球卻不被阻擋的繼續流入下游達成分離。分離電極旁設計側向流道，用來收集被阻擋之白血球，達成血球分離分類器的目標。經由數值計算來比較實驗的臨界速度，發現計算的估計是接近實驗結果的，驗證了實驗前初步分析的重要性。結果顯示，本裝置可達到每秒800顆血球分離分類的效率。 因實驗用之樣品是活體的細胞，細胞的介電性質會隨著樣品保存的時間而變化。因此，吾人記錄了各個保存時間和臨界速度的變化，來求得最佳的分離效率。本晶片不僅可分離血球，也具有裂解血球的能力，所以本晶片與其他微流體晶片具有高度之整合性，可輕易整合成一個完整的微分析系統。

This thesis presents a cell sorter that can be integrated into a lab-on-a-chip device for micro total analysis system. Erythrocytes and leukocytes are separated in a microchannel using dielectrophoresis (DEP). Different types of cells/particles have distinct dielectric properties in a particular medium, thus resulting different DEP force. We use the relationship between DEP and drag force to separate and sort the cells. This study shows that a DEP wall can be induced to block large number of leukocytes while letting the erythrocytes pass. Comparison of maximum flow velocity that DEP force is effective in blocking the leukocyte agrees well between experiment and simulation. Results show a sorting rate of about 800 cells per second is achieved. The sorting device is designed with side channels to draw leukocytes out and approaches the sorting goal. We also obtain the relationship between storage time of blood cell and maximum flow velocity, in order to find the best opportune time for separation. This device not only can sort and separate different cells, but also have ability to lyse cells. Therefore, it is a well-integrated microchip with other devices, such as cell counter, PCR chip, and etc.