An integrated microchip for dielectrophoresis based characterization and manipulation of cells

In the past, a variety of complementary techniques such as dielectrophoretic levitation, electrorotation and Travelling Wave Dielectrophoresis (TWD) have each been individually and effectively applied in demonstrating the promising applications of DEP in the life and biological science. In this regard, however, little effort has been devoted to the development of an integrated platform that enables simultaneous such manipulations and measurements on a single microfabricated chip. In this paper we discuss the design and implementation of a single microchip (3mm x 6 mm) onto which three types of microelectrodes of similar geometric layouts but various functions were integrated. Yeast and plant protoplasts known to have well-characterized dielectric properties as test particles were used to investigate the electrokinetic behaviors for these electrodes as a function of frequency and electrode excitation mode. Several characteristic cell electrokinetic behaviors were identified, including linear conveyance, electrorotation and levitation in different regions of the frequency spectrum. The experimental observations demonstrated the feasibility and adaptability of combining the three main electrokinetic effects of DEP as a system on a single microchip platform in a compact manner.