Design, Simulation and Experiments of apparatus for electrorotation

電旋轉現為成功的生醫檢測工具，特別是在細胞的檢測應用更為廣泛。本研究目的，為設計最佳化電旋轉設備，其一設備可以提供最大抓取微粒的區域內，同時擁有穩定介電力距。文中，我們計算電場，總介電泳力(包括傳統介電泳力與旅波式介電泳力)、介電力矩與粒子群二維與三維設備中的運動軌跡。在考慮介電泳抓取微粒的穩定性 (穩定的將微粒抓取於流道中間)，與介電力距的等值性的情形下，我們得知在改變電極的特徵長度( 電極長度/裝備長度)，可得到最佳化電旋轉設備。借由數值分析後，本研究得知當 ，可擁有極佳的電旋轉設備，因此我們得知改變電極的特徵長度，來改善電旋轉設備是可行的。就三維電旋轉設備，文中引入實驗常使用的，上下四片電極組來進行模擬。在實驗與模擬結果的相互驗證下，可得知本研究所建立之模擬結果的正確性，並對往後電旋轉裝備，對於細胞檢測的應用，提供更穩定與擴大其應用範圍。Electrorotation is a successful tool for the characterization of particles, in particular, the biological particles. Here we propose a design of the chamber which might have better performance for electrorotation. An optimal chamber is the one that possesses a maximized trapping region of essentially constant and maximized torque on the particles. We have calculated the electric field, the total dielectrophoretic force (including both the conventional and traveling wave dielectrophoretic forces), the dielectrophoretic torque, and trajectories of many particles inside various 2D/3D chambers. By considering both the trapping ability of the particles and the variation of the across the chamber, we found that the ratio of the electrode width to channel width is a crucial parameter. Numerical results for different 2D/3D cases indicate that is the optimize range for the design. A 3D rectangular chamber with four electrodes on both the upper and lower walls is a promising candidate for particle application. Our method is validated by comparing with the analytic solution of a 2D model problem and with experiment in a 3D chamber.CONTENTSCKNOWLEDGMENTS I文摘要 IIBSTRACT IIIHAPTER 1 INTRODUCTION 1 1.1 BACKGROUND 1 1.2 LITERATURES SURVEY 3 1.3 MOTIVATION AND OBJECTIVE 5HAPTER 2 THEORY 7 2.1 ELECTROSTATICS 7 2.2 GENERAL DIELECTROPHORESIS 8 2.3 VISCOUS FORCE AND TORQUE ON SPHERICAL PARTICLES 12HAPTER 3 NUMERICAL METHOD 17 3.1 ELECTRIC FIELD SIMULATION 17 3.2 PARTICLE MOTION 18 3.3 INITIAL CONDITIONS AND BOUNDARY CONDITIONS 19HAPTER 4 RESULT AND DISCUSSION 21 4.1 GRID DEPENDENCE TEST 21 4.2 MODEL PROBLEM FOR PROGRAM VALIDATION 23 4.3 REAL PROBLEM FOR THE 2D ELECTROROTATION CHAMBER 26 4.3.1 Square electrode array 27 4.4 2D CHAMBER WITH POLYNOMIAL ELECTRODE 29 4.5 3D ELECTROROTATION CHAMBER 31 4.5.1 Grid dependence test 31 4.5.2 Levitation height calculation 32 4.6 THREE DIMENSIONAL CHAMBER WITH 4 RECTANGULAR ELECTRODES AT THE BOTTOM WALL 33 4.7 THREE DIMENSIONAL CHAMBER WITH ON BOTH THE LOWER AND UPPER WALLS 34HAPTER 5 EXPERIMENTS 36 5.1 SYSTEM FABRICATION 36 5.1.1 Electrodes 36 5.1.2 Channel 37 5.2 Experiment process 38 5.3 ROTATION SPEED MEASUREMENT 38 5.4 COMPARISON BETWEEN EXPERIMENT AND CALCULATION 39HAPTER 6 CONCLUSION AND FUTURE WORKS 40 6.1 CONCLUSIONS 40 6.2 FUTURE WORKS 40EFERENCE 4