Dielectrophoretic field cages made from indium tin oxide: Trapping of submicron particles within transparent electrode structures

Indium tin oxide (ITO) layers on glass have been structured by KrF excimer laser ablation into planar electrode arrays. These have been assembled to form three-dimensional hybrid structures and energized by high-frequency (1-50 MHz) a.c. Particulate materials of different origin, suspended in aqueous solutions, can be manipulated using negative dielectrophoresis. Polystyrene latexes of submicrometer diameter and viable mammalian cells have been trapped in dielectrophoretic field cages made from ITO, as previously shown for noble metal electrodes. Optical observation of the trapped objects is facilitated by the transparency of the electrode material. Fine-structured ITO electrodes can be used for contactless particle handling in complex microsystems.