微全分析系統(micro total analysis systems, μTAS)，稱之微晶片實驗室(lab-on-a-chip)，或是微型化分析系統，可將活細胞樣品液操縱分離且可完成分解析、快速、低成本之分析，在生物學和化學有廣大前景與應用。這些操控的能力包括隔離或偵測稀少的癌細胞、從稀釋的溶液中聚集細胞、根據細胞特性分離細胞以及抓取且定位單一細胞並加以辨識細胞。因此電學、光學、磁學及力學的方法不僅被廣泛運用在操控細胞的科技上，也被整合到微晶片上用來抓取細胞。介電泳為一種中性粒子受到外加電場極化後產生的運動行為，可使微生物在沒有損害的情形下聚集起來，而作用在細胞上的介電泳力為細胞分離機制，分類過程中不會損害供研究之樣品活細胞。藉由CFD-ACE+商用軟體的模擬得知利用低導電度的四角型結構物所產生的無電極式的介電泳之設計，會將微粒子抓取在兩結構物中間的區域，使得細胞可以承受不穩定的流場作用，根據模擬分析的結果，得到結構物的間距離以及施加電壓對介電泳力的影響，由實驗更進一步得到結構物的間距、施加電壓以及微流道流速對微晶片抓取微小粒子的能力之影響。本研究的目的在於探討應用介電泳力之原理研發微抓取器，並探討結構物的間距、施加電壓、微流道流速對微晶片抓取微小粒子的能力之影響，藉以完成微抓取粒子器。

The area of micro total analysis systems(μTAS), also called “lab on a chip”, or miniaturized analysis systems, is growing rapidly, promise wide applications in biology and chemistry for manipulating samples in suspension to achieve high resolution, fast, and low-cost analysis and synthesis. For these purposes, electric, optical, magnetic, and mechanical forces have been widely used not only as conventional manipulation principles, but also as trapping methods to be integrated in microchip. Dielectrophoresis (DEP), the motion of a particle caused by an applied electric field gradient, can concentrate microorganisms non-destructively. The DEP force as trapping mechanism has the advantage of no risk to the sample. We have developed an alternative method in which a arrangement of insulating trapezoids in a channel of a microchip produce the spatially nonuniform fields for electrodeless dielectrophoretic trapping. Cells are trapped between the trapezoids structures and held against destabilizing flows by dielectrophoretic forces. We have improved the design of electrodeless DEP geometries, correlated particle acted by DEP effects with electrical-field distributions determined through insulating microstructures produce non-uniform electric fields to drive DEP in microsystems. Parameters of structure as being analyzed the effect on the magnitude of DEP force to analysis their influence on the trapping ability. This study is attempt to research on microfluidic trapping by using Dielectrophoresis (DEP) force and to investigate the relation on important parameters of microchip device for our design to comprehend the factors containing the spacing between two structures, the applied voltage and flow velocity.

[1] S. Umehara, Y. Wakamoto, I. Inoue, K. Yasuda. (2003) On-chip single-cell microcultivation assay for monitoring environmental effects on isolated cells. Biochem. Biophys. Res. Commun. Vol. 305, pp. 534-540.
[2] J. Enger, M. Goks¨or, K. Ramser, P. Hagberg, D. Hanstorp. (2004) Optical tweezers applied to a microfluidic system, Lab on a Chip, Vol. 4, pp. 196-200.
[3] R.A. Flynn, A.L. Birkbeck, M. Gross, M. Ozkan, B. Shao, M.M. Wang, S.C. Esener. (2002) Parallel transport of biological cells using individually addressable VCSEL arrays as optical tweezers. Sens. Actuators B, Vol. 87, pp. 239-243.
[4] A.L. Birkbeck, R.A. Flynn, M. Ozkan, D.Q. Song, M. Gross, S.C. Esener. (2003) VCSEL arrays as micromanipulators in chip-based biosystems. Biomed. Microdevices, Vol. 5, pp. 47-54.
[5] P.Y. Chiou, A.T. Ohta, M.C. Wu. (2005) Massively parallel manipulation of single cells and microparticles using optical images. Nature. Vol. 436, pp. 370-372.
[6] M.P. MacDonald, G.C. Spalding, K. Dholakia. (2003) Microfluidic sorting in an optical lattice. Nature, Vol. 426, pp. 421-430.
[7] M. Toner, and D. Irimia. (2005) Blood on a chip. Annu. Rev. Biomed. Eng. Vol. 7, pp. 77-103.
[8] M. Berger, J. Castelino, R. Huang, M. Shah, R.H. Austin. (2001) Design of a microfabricated magnetic cell separator. Electrophoresis,Vol. 22, pp.3883-3892.
[9] H. Lee, A.M. Purdon, R.M. Westervelt. (2004) Manipulation of biological cells using a microelectromagnet matrix. Appl. Phys. Lett. Vol. 85, pp.1063-1065.
[10] V.I. Furdui, D.J. Harrison. (2004)Immunomagnetic T cell capture from blood for PCR analysis using microfluidic systems, Lab on a Chip, Vol. 4, pp. 614-618.
[11] P. Grodzinski, J. Yang, R.H. Liu, M.D. Ward. (2003) A modular microfluidic system for cell pre-concentration and genetic sample preparation. Biomed. Microdevices, Vol. 5 , pp. 303-310.
[12] D.W. Inglis, R. Riehn, R.H. Austin, J.C. Sturm. (2004) Continuous microfluidic immunomagnetic cell separation. Appl. Phys. Lett. Vol. 85, pp. 5093-5095.
[13] K.H. Han, A.B. Frazier. (2004) Continuous magnetophoretic separation of blood
cells in microdevice format. J. Appl. Phys. Vol. 96, pp. 5797-5802.
[14] L. Zhu, Q. Zhang, H.H. Feng, S. Ang, F.S. Chau, W.T. Liu. (2004) Filter-based microfluidic device as a platform for immunofluorescent assay of microbial cells. Lab on a Chip, Vol. 4, pp. 337-341.
[15] H. Mohamed, L.D. McCurdy, D.H. Szarowski, S. Duva, J.N. Turner, M. Caggana. (2004) Development of a rare cell fractionation device: application for cancer detection. IEEE Trans. Nanobiosci. Vol. 3, pp. 251-256.
[16] J. Moorthy, D.J. Beebe. (2003) In situ fabricated porous filters for microsystems.
Lab on a Chip, Vol.3, pp. 62-66.
[17] L.R. Huang, E.C. Cox, R.H. Austin, J.C. Sturm. (2004) Continuous particle separation through deterministic lateral displacement. Science, Vol. 304, pp. 987-990.
[18] A. Khademhosseini, J. Yeh, S. Jon, G. Eng, K.Y. Suh, J.A. Burdick, R. Langer. (2004) Molded polyethylene glycol microstructures for capturing cells within microfluidic channels. Lab on a Chip, Vol. 4, pp. 425-430.
[19] H. Tani, K. Maehana, T. Kamidate. (2004) Chip-based bioassay using bacterial sensor strains immobilized in three-dimensional microfluidic network. Anal. Chem. Vol. 76, pp. 6693-6697.
[20] A. Revzin, R.G. Tompkins, M. Toner. (2003) Surface engineering with poly(ethylene glycol) photolithography to ereate high-density cell arrays on glass. Langmuir , Vol. 19, pp. 9855-9862.
[21] M. Durr, J. Kentsch, T. Muller, T. Schnelle, M. Stelzle. (2003) Microdevices for
manipulation and accumulation of micro- and nanoparticles by dielectrophoresis. Electrophoresis, Vol. 24, pp. 722-731.
[22] Y. Huang, S. Joo, M. Duhon, M. Heller, B. Wallace, X. Xu. (2002) Dielectrophoretic Cell Separation and Gene Expression Profiling on Microelectronic Chip Arrays. Anal. Chem. Vol. 74, pp. 3362-3371.
[23] J. Voldman, M.L. Gray, M. Toner, M.A. Schmidt. (2002) A microfabrication-based dynamic array cytometer. Anal. Chem. Vol. 74, pp. 3984-3990.
[24] F. Arai, A. Ichikawa, M. Ogawa, T. Fukuda, K. Horio, K. Itoigawa. (2001) High-speed separation system of randomly suspended single living cells by laser trap and dielectrophoresis. Electrophoresis, Vol. 22, pp. 283-288.
[25] L. Cui, D. Holmes, H. Morgan. (2001) The dielectrophoretic levitation and separation of latex beads in microchips. Electrophoresis, Vol. 22, pp. 3893-3901.
[26] H. Li, R. Bashir. (2002) A time resolved study of the response of a WO3 gas sensor to NO2 using AC impedance spectroscopy. Sens. Actuators B, Vol. 86, pp. 215-221.
[27] U. Seger, S. Gawad, R. Johann, A. Bertsch, P. Renaud. (2004) Cell immersion
and cell dipping in microfluidic devices. Lab on a Chip. Vol. 4, pp. 148-151.
[28] S. Chu, “ Laser manipulation of atoms and particles, “ (1991) Science, Vol. 253, pp. 861-866
[29] S. Chu, “ Laser manipulation of atoms and particles, “ (1991) Science, Vol. 253, pp. 861-866
[30] T. Lea, J. P. O’Connell, K. Nustad, S. Funderud, A. Berge, and A. (1990)
Rembaum, “Microspheres as immunoreagents for cell identification and cell fractionation,” in Flow Cytometry and Sorting, M. R. Melamed, T. Lidmo, and M.L. Mendelsohn, Eds. New Uork: Wiley-Liss
[31] A.R. Minerick, R. Zhou, P. Takhistov, H.C. Chang. (2003) Manipulation and characterization of red blood cells with alternating current fields in microdevices. Electrophoresis, Vol. 24, pp. 3703-3717.
[32] M.A. Witek, S.Y. Wei, B. Vaidya, A.A. Adams, L. Zhu, W. Stryjewski, R.L. McCarley, S.A. Soper. (2004) Cell transport via electromigration in polymer-based microfluidic devices. Lab on a Chip, Vol. 4, pp. 464-472.
[33] J.J. Hawkes, R.W. Barber, D.R. Emersonb, W.T. Coakley. (2004) Continuous cell washing and mixing driven by an ultrasound standing wave within a microfluidic channel. Lab on a Chip, Vol. 4, pp. 446-452.
[34] M. Yoshida, K. Tohda, M. Gratzl. (2003) Hydrodynamic Micromanipulation of Individual Cells onto Patterned Attachment Sites on Biomicroelectromechanical System Chips. Anal. Chem. Vol. 75, pp. 4686-4690.
[35] Huang, Y., and R. Pethig. (1991) Electrode design for negative dielectophoresis.
Meas. Science Technology. Vol. 2, pp. 1142-1146
[36] Marszalek, P., J. J. Zielinski, and M. Fikus. (1989) Experimental verification of a
theoretical treatment of the mechanism of dielectrophoresis. Bioelectrochem. Bioenerg. Vol. 22, pp289-298
[37] Pohl, H. and K. Pollock. (1978). Electrode geometries for various dielectrophoretic force laws. J. Electrostatics. Vol. 5, pp. 337-342
[38] Pethig, R., Y. Huang, X. B. Wang, and J. P. H. Burt. (1992) Positive and negative dielectrophoretic collection of colloidal particles using interdigitated castellated microelectrodes. J. Phys. D: Appl. Phys. Vol. 24, pp881-888
[39] Gray, D. S., J. L. Tan, J. Voldman, and C. S. Chen. (2004) Dielectrophoretic registration of living cells to a microelectrode array. Biosens. Bioelectron. Vol. 19, pp. 771–780.

[40] Wang, X., Hughes, M.PP., Huang, Y., Becker, F., Gascoyne, PP.R.C. (1995) Non-uniform spatial distributions of both the magnitude and phase of AC electric fields determin dielectrophoretic forces. Biochimica et Biophysica Acta, Vol, 1243, pp. 185-194.
[41] Washizu, M., and O. Kurosawa. (1990) Electrostatic manipulation of DNA.
[42] P. Singh, and N. Aubry. (2005) Trapping force on a finite-sized particle in a dielectrophoretic cage. Phys. Review E, Vol. 72, pp. 016602-1-5
[43] Adam Rosenthal and Joel Voldman. (2005) Dielectrophoretic traps for single-particle patterning. Biophys. J., Vol. 88, pp. 2193-2205
[44] W. Michael Arnold, Senior Member. (2001) Positioning and levitation media for the separation of biological cells. IEEE Trans. Ind. Appl., Vol. 37, pp. 1468-1475
[45] G. H. Markx, Y. Huang, X. F. Zhou.(1994) Dielectrophoretic characterization and separation of micro-organisms, Microbiology, Vol. 140, pp. 585-591
[46] Gascoyne, P. R. C., J. Noshari, F. F. Brecker, and R. Pethig. (1994) Use of dielectrophoretic collection speatra for characterizing differences between normal and cancerous cells. IEEE Trans. Appl. Vol. 30, p. 829-834
[47] Talary, M., K. I. Mills, T. Hoy, A. K. Burnett, and R. Pethig.(1995) Dielectrophoretic separation and enrichment of CD34+ cell subpopulation from bone marrow and peripheral blood stem cells. Med. Biol. Eng. Comp, Vol. 33, pp. 235-237
[48] M. Washizu, T. Nanba, S. Masuda. (1990) Handling biological cells using a fluid integrated circuit, IEEE Trans. Ind. Appl., Vol. 26, pp. 352-356
[49] Muller, T., G. Gradl, S. Howitz, S. Shirley, T. Schnelle, and G. Fuhr. (1999) A 3-D microelectrode system for handling and caging single cells and particles. Biosens. Bioelectron. Vol. 14, pp. 247-256
[50] Asbury, C. L., and G. van den Engh. (1998) Trapping of DNA in nonuniform oscillating electric fields. Biophys. J., Vol. 74, pp. 1024-1030
[51] Chia-Fu Chou, Jonas O. Tegenfeldt, Olgica Bakajun, Shirley S. Chan, Edward C. Cox, Nicholas Darnton, Thomas Duke, and Robert H. Austin.(2002) electrodeless dielectrophoresis of single- and double-stranded DNA. Biophys. J., Vol. 83, pp. 2170-2179
[52] Adam Rosenthal and Joel Voldman (2005). Dielectrophoretic traps for single-particle patterning. Biophysical Journal, Vol. 88, pp. 2193-2205.
[53] Pohl, H.A. (1978). Dielectrophoresis. Combridge University Press.
[54] Wang, X., Wang, XB., Bechker, and F., Gascoyne, P. (1998) A theoretical method of electrical field analysis for Dielectrophoretic electrode arrays using Green’s theorem. Journal of Physics. D: Appl. Phys., Vol. 29, pp. 1649-1660
[55] Goldman, A., Cox, and H. Brenner. (1967) Slow viscous motion of a sphere parallel to a plane wall. Ⅱ. Couette flow. Chem. Eng. Sci., Vol. 22, pp. 653-660
[56] Deen, W. M. (1998) Analysis of transport phenomena. Oxford University Press, New York.
[57] Cherukat, P. and J. B. McLaughlin. (1994) The inertial lift on a rigid sphere in a linear shear-flow field near a flat wall. J. Fluid Mech. Vol. 263, pp. 1-18
[58] Leighton, D. and A. Acrivos. (1985) The lift on a small sphere touching a plane in the presence of a simple shear flow. Journal of Applied Mathematics and Physics, Vol. 36, pp. 174-178
[59] Altomare, L., Borgatti, M., Medoro, G., Manaresi, N., Tartagni, M., Guerrieri, R., and Gambari, R. (2003) Levitation and movement of human tumor cells using a printed circuit board device based on software-controlled dielectrophoresis. Biotechnology and Bioengineering, Vol. 82, pp. 474-479.
[60] Durr, M., Kentsch, J., Muller. T., Schnelle, T., and Steizle, M. (2003) Microdevices for manipulation and accumlation of micro-and nanoparticles by Dielectrophoresis. Electrophoresis, Vol. 24, pp. 722-731.
[61] Holmes, D., Green N.G., and Morgan, H. (2003) Microdevices for Dielectrophoretic flow-through cell separation. IEEE Engineering in Medicine and Biology Magazine, Nov. /Dec., pp. 85-90.
[62] Green, N.G., Morgan, H. (1997) Dielectrophoretic separation of nano-parrticle. Journal of Physics D: Appl. Phys. Vol. 30, pp. L41-L44
[63] Pethig, R., markx, G..H. (1997). Applications of Dielectrophoresis in biotechnology. TibTech, Vol. 15, pp. 426-432.
[64] Green, N. G., and H. Morgan. (1997) Dielectrophoretic investigations of submicrometre latex spheres. J. Phys. D: Appl. Phys. Vol. 30, pp. 2626-2633.
[65] Green, N. G., and H. Morgan. (1999) Dielectrophoresis of sub-micrometre latex spheres. Part I: experimental results. J. Phys. Chem. B. Vol. 103, pp. 41-50.