| New and improved techniques to sort and characterize living cells and particles are in high demand for wide applications in areas such as biomedical research, clinical diagnosis, and environment analysis. The technique of dielectrophoresis has been proven to play a significant role for such purpose, especially when it is implemented through photolithography and etching technology in contitution of micromachined fluidic microsystems.; This thesis will describe the utility of the dielectrophoresis effect, employing planar microelectrode arrays fabricated on a glass substrate to synthesize a specially shaped nonuniform field, for fractionating cells into purer subpopulations. The establishment of fluid flow in the separating chamber, which also contributes to the separation, has been experimentally investigated. Three practical validation modes are proposed, however, a detailed account is only presented for one mode of operation. Both the simulation for the electric field and the real experiment confirm our theoretical predictions and furthermore demonstrate the improvements in separation efficiency and throughput over a wide range of applied field frequencies. |
