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Dielectrophoresis


Two droplets are merged using dielectrophoresis.

Dielectrophoresis (DEP) involves the creation of forces on polarizable particles to induce movement in non uniform electric fields (usually AC electric fields). Dielectrophoretic forces can be used to characterize, handle and/or manipulate microscale and nanoscale bioparticles. This can include sorting, trapping and separating cells, viruses, bacteria, DNA, and the like. DEP can be fully accounted for in FLOW-3D and can be activated along with all other fluid flow options available in the code, such as one-fluid or two-fluid flow, with or without sharp interfaces.

 

Bio-MEMS: Dielectrophoretic Trapping of Cells

Electric potential distribution simulated by FLOW-3D
From the left: electric potential
distribution created by the electrodes; electric
field strength distribution, and cell distribution.

Setting up a flow simulation using cell culture chamber geometry
Cell culture chamber

Dielectrophoresis plays a very important role in the characterization, handling and manipulation of microscale and nanoscale bioparticles (cells, viruses, bacteria, DNA, etc.). The pictures at right are from a FLOW-3D simulation of cells being trapped in a cylindrical cell culture chamber with microelectrodes placed on the chamber bottom.

As expected, strong electric field strength is observed near the edges of electrodes. In particular, a "well" in the center of the chamber, with minimum electric field strength at its center, is formed where cells are trapped.

The chamber geometry is displayed in the figure at left. It is a chamber with a diameter of 800 microns and a depth of 100 microns. There are four microscale electrodes deposited on a cross section 5 microns above the chamber bottom which provide the electric potential. The magnitude of the rms (root mean square) value of electric potential on the electrode surface is 3 volts.