Droplet and particle manipulation in emulsions and suspensions using 3D electro-osmotic micropumps

This paper presents investigations on droplet and particle manipulation in microfiuidic channels realized in SU-8/glass technology, which is based on a competitive interplay of viscous drag, gravitational, buoyancy and dielectrophoretic forces. The latter are induced by alternating current (AC) driven three-dimensional (3D) stepped electrode arrays in the channel, enabling so called 3D AC electro-osmotic pumping, as it has been proposed recently. Due to size- and density-dependent differences in polarizability, targeted particles resp. droplets in the fluid stream can be slowed down or even pinned above the electrode structures by adjusting the operation parameters of the pump. Hence the presented device can be utilized for simultaneous pumping and manipulation of droplets and particles in emulsions and suspensions.