Precise Positioning of Particles in Microwells within Horizontal DEP Cages

An efficient method to trap and analyze particles avoiding excessive electric field strength is to use negative dielectrophoretic cages, where particles find stability in the electric field minimum. We present a novel structure where particles are trapped and forced to interact within microwells opened at top and bottom sides by creating a cylindrical negative dielectrophoretic cage. This approach provides a controlled alignment of the particles along a predefined axis. An array of microwells is built by drilling through holes with a diameter of 150 µm on a flexible printed circuit board with two Cu/Au layers separated by one polyimide layer, providing a cheap and disposable device. Levitation of one or two polystyrene beads with a diameter of 25 µm in DI-water was experimented confirming the positioning predicted by physical simulations. Vertical position of the particles as a function of the amplitude of polarization signals was extracted from simulations and confirmed by experimental results.