Measurement of dielectrophoretic mobility of single micro-particles in a flow channel.

A new device to measure the dielectrophoretic mobility alpha of a single micro-particle in a micro-flow system has been proposed. From the velocity analysis of the micro-particle flowing between a pair of parabolic electrodes, the value of alpha could be obtained.

Effects of viability and lectin protein binding on dielectrophoretic behavior of single yeast cells.

The dielectrophoretic (DEP) behavior of individual yeast cells (5-7 microm in diameter) in aqueous media was observed in a fabricated planar quadrupole microelectrode with a working area of 100 microm in diameter by an optical microscope. The yeast cells migrated in the radial direction in the working area. The DEP velocity of the cells increased as they approached the electrode. The DEP trajectory of the cells was analyzed with a theoretical equation derived previously, and the dielectrophoretic mobility was determined. The dielectrophoretic mobility was found to be affected by the viability of cells, the conductivity of the medium, and the binding of lectin protein (concanavalin A) to the cell surface. These DEP behaviors were analyzed based on the permittivities and conductivities of the cell interior and wall, and those of the medium.