Dielectrophoretic force measurements in yeast cells by the Stokes method

A chamber and method for the measurement of dielectrophoretic (DEP) force in yeast cells (Saccharomyces cerevisiae) is described. The physical method uses the Stokes drag force and a V-shaped chamber. Velocity measurements were induced over the frequency range of between 50 kHz and 5 MHz for a suspending medium of 2.2 mS/m in conductivity. Average values of DEP force and effective polarizability have been determined from the velocity measurements. Experimental data with single cells confirm the theoretical expression for the axial profile of the electric field. The results show that this method-and-chamber system is an accurate tool for measuring of DEP force over single cells. Population data of 129 cells confirm the theory showing that the DEP velocity distribution density of the population is similar to the cellular “square radius”