到目前為止，在生命科學方面上微型化是近期內的主要趨勢。隨著微機電技術的發展，使得在過去幾十年裡發展出許多微流體元件，如：微混和器、微閥門和樣品的檢測器。隨著實驗室晶片技術的進步，使得微機電元件符合生物分子尺度，因此在過去幾十年裡，吸引了許多研究者在生物領域上應用的興趣，並且投入許多心血與努力。細胞許多的行為並非單靠單一刺激，而是結合許多複雜的化學刺激反應而有的生物反應。因此化學濃度梯度產生器在研究許多生物行為過程是一個很重要的工具，此論文即研究細胞受到不同化學濃度環境下的反應行為。
本研究為設計一實驗室晶片以觀察與分析細胞在趨化因子(chemotactic)濃度梯度環境上的相關遷移情形。利用一些複雜的流道結構設計來提升擴散效率以快速產生穩定且連續的趨化因子濃度梯度。藉由施予不同頻率的交流電壓，使細胞表面被極化成電偶極的基礎下，利用介電泳的概念去操控細胞群，使其在趨化因子濃度梯度下能快速精確分佈在特定位置以利研究其生物行為。以上所有功能皆以簡單的製程整合於一晶片上。

Up to now, miniaturization is the recent trend in life sciences. With the emergence of MEMS technologies, many microfluidic components, such as micromixers, microvalves and sample dispensers were developed over the past decade. With the advancement of lab-on-a-chip technology, the applications in biological field have been attracting a significant attention in the past few decades. Complex cellular responses do not only depend on one stimulus but on the integrated information from several stimulus. The concentration gradient generator is an important tool in many biological processes. One of the biological processes is chemotaxis that this thesis wants to study.
This research presents a Lab-on-a chip device to achieve and study cells migration in chemotactic concentration gradient. Used the channel geometry complicated enough to fast produce the stable and continued chemotatic concentration gradient. Based on the polarity difference within cells caused by applying different frequencies of the input voltage, we could use the concept of dielectrophoresis (DEP) to control cells to distribute uniformly on a horizontal line in chemotactic concentration gradient for studying the behavior of cells. These functions could be all integrated on a chip and achieved with easy fabrication process.

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