Manipulation of Particles Using Dielectrophoresis

Arun Thankamony John Kadaksham

Advisor: Dr. P. Singh

Abstract

The Phenomenon of dielectrophoresis in micro electrodes is studied both numerically and experimentally. The numerical study is performed by using a scheme based on the distributed Lagrange multiplier method (DLM), where the fluid equations are solved exactly and the electrostatic interactions are modeled using the point dipole approximation. Simulations show that the particle collection is influenced by a parameter defined by the ratio of electrostatic particle-particle interaction and dielectrophoretic forces. When the magnitude of this parameter is less than order one, particles move to the regions of high or low electric field regions individually, without the formation of particle chains. However, when the magnitude of this parameter is greater than order one, particles regroup into chains which then move toward the electric field maximums or minimums without breaking. Experiments were conducted in micro electrodes manufactured by MEMS processes using yeast cells grown and suspended in water. Experimental observations are found to be in agreement with the numerical simulations.