Mezić Research Group

Dynamical Systems and Nonlinear Control Theory

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Reference Details
Loire, Sophie and Mezic, Igor (2009), "Joint use of traveling wave dielectrophoresis and AC-electroosmosis for particle manipulation", ASME Conference Proceedings.

We present a microfluidic device that uses both traveling wave dielectrophoresis and AC electroosmotic fluid flow to sort bacteria from other particles and increases the bacteria output concentration. The device consists of a thin and long rectangular channel, 40 microns tall, 400 microns wide and one mm long. Two interdigitated electrode arrays one at the bottom and one at the top of the channel are used to generate a nonuniform electric field. A four-phase signal at high frequency superposed with a low frequency signal is applied to the electrodes. Bacteria from 0.5 to 2 microns are brought into the channel at a flow of 10 microL/min in a fluid medium with a conductivity of 10 mS/cm. Bacteria are pushed away from the electrodes toward the center of the channel by negative dielectrophoresis while the traveling wave component moves them to one side of the channel. Particles in the fluid experiencing positive dielectrophoresis collect on top of the electrodes. The low frequency signal is used to generate an additional AC electroosmotic fluid flow above the electrodes that lowers the channel length at which all bacteria are found to reside only on one side of the channel. At the end of the channel, the fluid is collected in two outputs: the bacteria are collected on one side and fluid without bacteria is collected on the other side.