In this paper, we study the manipulation and immobilization of micro- and nano-sized particles, such as living cells, suspended in a liquid. Our technique focuses on dielectrophoresis, that is, the use of spatially nonuniform electric field, while not damaging the manipulated particles or cells. The small size of the particles considered here requires the use of micro-electro-mechanical device (MEMS). We first simulate the suspended system by means of our new computational fluid dynamics (CFD) tool based on the distributed Lagrange Multiplier method (DLM), which takes into account not only fluid-particle but also particle-particle interactions. Results for both positive and negative dielectrophoresis are presented. We also show the existence of various regimes for the particle structures depending on the relative magnitude of the dielectrophoretic force and the electrostatic particle-particle interactions. We then design, fabricate and test a MEMS platform containing several microdevices.
