High-gradient electric field system for the dielectrophoretic separation of cells

A high-gradient electric field strength system, consisting of a chamber created from two concentric cylindrical electrodes and filled with glass beads, was constructed for the study of the dielectrophoretic separation of cells. The glass beads distort the electric field patterns and generate sites of high electric field gradients, which can capture cells by dielectrophoresis. In order to experimentally determine the efficacy of the system, yeast cells were injected into a constant flow through the system, and the number of cells trapped measured. The effects of changes in voltage, bead size and the size of the inner and outer electrodes on the trapping efficiency of the dielectrophoretic separation system were investigated. In addition, simulation and electric field analysis were carried out using FEMLAB. Results indicate that the trapping of cells occurs by a combination of mechanical trapping and dielectrophoresis. Analysis of the results allow predictions to be made for the optimum values of the voltage, bead size and size of inner and outer electrode for any high-gradient system, in order to generate sufficient electric field gradient for dielectrophoretic cell collection whilst reducing non-specific mechanical trapping.