本研究完成三種架構之單細胞捕捉晶片，利用微機電製程建立陣列式介電泳電極，並利用負介電泳力(Negative Dielectrophoresis force, N-DEP Force) 捕捉單一細胞於預期的位置，得以進一步進行細胞凋亡研究或是藥物篩檢的目的。本研究有別於平面式的介電泳電極設計，而是利用上、下層電極、微流管道、以及SU-8三維碗形結構層製程技術，利用電極週期性分布與三維結構幾何扭曲其電場，形成縱向不均勻電場，得以迅速捕捉懸浮於微流管道中的細胞。此外，特殊線寬設計得以符合細胞的尺寸大小 (U937, 15-20 μm) 達到單細胞解析度之需求。而三維結構層則利用準分子雷射加工機建立。理論與模擬部分，使用商用軟體模擬三種架構之介電泳力，並且利用影像處理，推算出介電泳力。實驗結果顯示，此晶片於特定的電壓與頻率下(5 Vpp, 1kHz)，可於水溶液下有效地捕捉到乳膠粒子；且經試驗在適當之細胞緩衝液下，亦可捕捉到細胞；此外，本文並且探討內含不同奈米粒子之細胞的捕捉速率；進而利用此晶片進行粒子分離。本研究提供以介電泳力捕捉細胞之設計準則與製程範例。

This study is about designing and constructing novel single-cell trapping dielectrophoretic (DEP) biochipsm, which consist of arrayed electrods and microstructures. The underlying operational principle is based on negative-delectrophoresis to trap the cells under investigation. The DEP biochip, as different from other planar electrodes, is consisted of ITO top electrode, PDMS flow chamber, bottom electrode array and SU-8 3D microstructure array. In order to achieve single-cell resolution, we fabricate a chess-type bottom electrode array and a bowl-type 3D microstructure array based on excimer laser micromachining. Such a 3D structure not only yields a non-uniform electric field for DEP trapping but also enhances the positioning and immobilization of trapped cells.
In theoretical analysis and simulation, we use Comsol Multiphysics to simulate the DEP force in these biochips. We also use image processing to derive the velocity and acceleration of beads when subjected to DEP forces and flow dragging, and therefore estimate the magnitude of DEP force.
In experiments, the results show the chip can trap beads at specific electrical voltage and frequency (5 Vpp, 1 kHz), and trap cells in properly chosen media. We also trap the cells with different nano-paticles under the chip, and fractionate the different size beads. In summary, we propose a design and its fabrication method to trap cells by DEP, which has great potentials for measuring cell-membrane impendence and gene transfer in the future.

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