Dielectrophoretic orientation, manipulation and separation of live and heat-treated cells of listeria on microfabricated devices with interdigitated electrodes

Dielectrophoresis, the movement of particles in non-uniform AC electric field, was used to separate live and heat-treated Listeria innocua cells with great efficiency on micro-fabricated devices with interdigitated electrodes by utilizing the difference of dielectric properties between live and dead cells. Both live and dead cells are found to be only able to collect either at the centers of the electrodes in negative dielectrophoresis or at the electrode edges in positive dielectrophoresis. Cell viability was characterized by a rapid method using epifluorescence staining. The dependency of the applied AC signal's frequency on the dielectrophoresis of different cells, as well as the orientation of the cells on the electrodes in the dielectrophoresis, is also observed and discussed. This on-electrode manipulation and separation of cells can prove to be useful in micro-scale diagnostic applications in biochips.