Separation of submicron bioparticles by dielectrophoresis

Submicron particles such as latex spheres and viruses can be manipulated an d characterized using dielectrophoresis. By the use of appropriate microele ctrode arrays, particles can be trapped or moved between regions of high or low electric fields. The magnitude and direction of the dielectrophoretic force on the particle depends on its dielectric properties, so that a heter ogeneous mixture of particles can be separated to produce a more homogeneou s population. In this paper the controlled separation of submicron bioparti cles is demonstrated. With electrode arrays fabricated using direct write e lectron beam lithography, it is shown that different types of submicron lat ex spheres can be spatially separated. The separation occurs as a result of differences in magnitude and/or direction of the dielectrophoretic force o n different populations of particles. These differences arise mainly becaus e the surface properties of submicron particles dominate their dielectropho retic behavior. It is also demonstrated that tobacco mosaic virus and herpe s simplex virus can be manipulated and spatially separated in a microelectr ode array.