摘要
本文主要研究光電介電泳驅動細胞旋轉。經由分析光電介電泳系統的電場，發現可能形成旋轉電場。根據電路的概念和理論的探討更確信旋轉電場的存在。根據電旋的理論，一旋轉電場在適當頻率下可驅動酵母菌細胞旋轉。為了對電場做深入的分析，Relaxation Method被用來模擬系統中的電場。以上三種方法，都推導出光電介電泳系統中存在一旋轉的電場。
經實驗證實，在系統電壓為4伏特頻率10k赫茲下，光電介電泳成功的驅動酵母菌細胞旋轉。此時細胞的轉速每秒可達3轉左右且當細胞越靠近照光處，轉速就越快；等細胞進入照光區後轉速變慢而至停止。對此現象，本文提出兩種方法估算轉速。一種是考慮大範圍照光，而另一種考慮照光範圍近似一點時。計算的結果是，考慮大範圍照光我們能對轉速作初略的估計，而無法看出對照光位置的變化趨勢。若考慮照光範圍近似一點，則可以看出轉速對照光位置的趨勢，但是對於實際轉速範圍的估計仍然有限。
實務上，轉速的可由電壓的平方來控制，而電壓的控制是相當容易的。提出的簡單模型可以估計是否能產生旋轉，再由電壓作精確的控制對於實驗或是更進階的應用有莫大幫助。

關鍵字：介電泳、電旋

Abstract
This study investigated the electro-rotation of cells using optical dielectrophoresis (o-DEP) for the first time. The electro-rotation is the phenomenon that a rotating electric field drives particles/cells rotating. Analyzing the electric field in the o-DEP system, it is possible to produce a rotating electric field in o-DEP system. Moreover, the concept of the equivalent circuit and fundamental theory could show that a rotating electric field exists in o-DEP system. To precisely simulate the electric field, the relaxation method for electrostatic problems is applied. Above three methods can derives that there is a rotating electric field in o-DEP system.
Since simulation takes a lot of time, two models for estimating the rotation speed are proposed. One is developed for vast illuminated region in o-DEP; another is developed for locally illuminated region in o-DEP. However the first model could only used to estimate the order of the rotation speed the trends of rotation speed. Thus, it could be applied to determine whether particles/cells are able to rotate under a certain illuminated condition. The second one can depict the trend of the rotation speed after some modification but the magnitude of the rotation speed could not be estimated precisely using this model. Actually the control of rotation speed is easy in practice because it depends on the magnitude square of the electric field. These two models are able to help us estimate the rotation effect before experiment or application.
The electro-rotation using o-DEP can make both yeast cells and 3T3 cells rotating. The rotation speed of the yeast cells could reach 3rps under voltage of 4V and 10 kHz, but the rotation speed of the 3T3 cells is less than 1rps under voltage 5V and 50kHz. The rotation speed of both two kinds gets greater as yeast cells getting closer to the illuminated region and stop rotating when they are in the inner of the illuminated region.
Keyword: dielectrophoresis, electro-rotation

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