Precise positioning of particles in microwells within horizontal DEP cages
M. Lombardini, M. Bocchi, L. Giulianelli, R. Guerrieri
Keywords: dielectroforesis, trapping, microwells
Abstract:The analysis and manipulation of one or few biological cells or artificial particles in the micron size range is a fundamental requirement in various life sciences applications such as sorting of rare cells or high-efficient transforming of microorganisms. In this work we present a novel structure of opened microwells where particles are positioned by means of nDEP forces in a region close to the wall of the microwell and aligned along a horizontal axis. This approach will allow to easily characterize and manipulate cells by adding specific electrodes for impedance sensing, electroporation or electrofusion applications which will result to be in contact with the particle. An array of microwells is built by drilling through holes (ø300 µm) on a flexible printed circuit board with two metal layers, providing a cheap and disposable device. The microwells are opened at top and bottom sides and filled by capillarity thanks to a carrier providing a saline buffer. Particles are delivered by a dispenser positioned on top of the well. By opportune polarization of four electrodes, arranged on two layers, a horizontal cylindrical nDEP cage is formed. Levitation of one or two polystyrene beads (ø90 µm) in DI-water was experimented confirming the predicted positioning.