隨著微機電產業的蓬勃發展，實驗室晶片技術已變成近期的熱門領域。由於微機電元件符合生物分子尺度，因此在過去數十年間，吸引了許多工程與生物研究者的興趣，投入許多心血與努力，促成跨領域的結合。人工肝臟的建立是近年來在組織工程上一個重要的趨勢，但是希望大量且快速的建立出具有功能性的人工肝組織，以取代人體受傷的組織是非常難的。因此，有個新方向，在體外建構一個具有功能性的仿肝組織藉此觀察肝臟細胞在不同環境下，活性會如何的變化，也是一個被重視的議題。本論文希望重建肝小葉組織，並研究肝小葉結構在不同濃度藥物下的活性反應行為。
本研究為設計一實驗室晶片，透過晶片上電極的設計，藉由施予適當頻率的交流電壓，使細胞表面被極化成電偶極的基礎下，利用介電泳概念排列細胞，建立肝小葉的圖形。在肝小葉結構排列完成後，再經由微流道設計以及流阻的概念，產生一個持續灌流且藥物濃度梯度可以達到大幅差異的系統，最後流至四個生物反應器，產生對數分佈濃度的藥物，並觀察肝臟細胞活性反應。以上所有功能皆以簡單的製程整合於一晶片上。

With the development of Micro-Electro-Mechanical Systems (MEMS) industry, the Lab-on-a-chip technology becomes a popular field in recent days. Because the scale of micro-device matches with cellular molecule, the interdisciplinary combinations of biological and engineering fields have been attracting a significant attention in the past few decades. The establishment of artificial liver is a trend in tissue engineering. However, it is so hard and slow to arrive the final goal --replace the damaged tissue of human. For this reason, there is a new approach to use engineered tissue to study human tissue physiology and pathophysiology in vitro. In vitro studies could control the environmental factors in experiments to observe the molecular processes between cell to cell. In this thesis, rebuilding hepatic lobule and observing the reactions of liver cells under various environments are the main targets. This research presents a Lab-on-a-chip device to achieve the cell-patterning function. Based on the polarity difference within cells caused by applying suitable frequency of the input voltage, we could use the dielectrophoresis (DEP) to manipulate cells and form the pattern of the hepatic lobule. After the cell-patterning is finished, stable and continuous logarithmically-varying concentrations of drug is generated via designing the flow resistance of micro channels. Then, different concentrations of drug with culture media are injected into four bioreactors. Finally, we could observe the effect for liver cells under different concentrations of drug by using this Lab-on-a-chip device.

1. Introduction - 1 -
1.1 Background and Motivation - 1 -
1.2 Survey of Literature - 3 -
1.2.1 Steady state gradient generators in cell culture systems - 3 -
1.2.2 Cell Micropatterning - 8 -
1.2.3 Hepatic Tissue Engineering - 13 -
2. Device Development - 16 -
2.1 Domain Knowledge - 16 -
2.1.1 Dielectrophoresis - 16 -
2.1.3 Mass Transport on Microscale - 21 -
2.2Design Concept - 23 -
2.2.1Design of Microchannel - 23 -
2.2.2 Simulation of Microchannel - 25 -
2.2.3 Design and Simulation of Lobule-Mimetic-Stellate Electrode – Manipulation of Cells - 26 -
3. Micro Fabrication Process - 29 -
3.1 Process Flow - 29 -
3.2 Process Result - 30 -
4. Experimental Results - 31 -
4.1 Experimental Setup - 31 -
4.1.1 Instrument Setup - 31 -
4.1.2 Cell Culture - 33 -
4.1.3 Cell Preparation for DEP Manipulation - 33 -
4.1.4 Surface Treatment for Cell Adhesion Enhancement - 34 -
4.2 Experiment Results - 34 -
4.2.1 The Parameter Setup for DEP Operation - 34 -
4.2.2 DEP Manipulation of heterogeneous cells - 35 -
4.2.2.1 On-chip Cell-patterning Demonstration of HMEC-1 Cells - 35 -
4.2.2.2 On-chip Cell-patterning Demonstration of HepG2 Cells - 36 -
4.2.3 Gradient Experiment - 37 -
4.2.3.1 Preliminary Test - 37 -
4.2.3.2 The Parameter Setup and Material Preparation for Drug Test - 40 -
4.2.3.3 The Result of HepG2 Activity Test - 44 -
5. Discussion and Future Work - 46 -
References - 48 -

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