Dielectrophoretic effect of nonuniform electric fields on the protoplast cell

In recent years, dielectrophoresis based microfluidics systems have been used to manipulate colloids, inert particles, and biological microparticles, such as red blood cells, white blood cells, platelets, cancer cells, bacteria, yeast, micro‌organisms, proteins, DNA, etc. In the current study the governing electric potential equations have been solved in the presence of cell for the purpose of studying particle-electric field dielectrophoretic interaction. Immersed Interface Method (IIM) which is a modified finite difference method is used to solve the governing 2D elliptic electrostatic equations with irregular boundaries. A neutral particle polarizes under the application of an electric field and causes local nonuniformity in electrostatic potential distribution. So cells experience electric stresses on its surface. The electric stress on cell surface is calculated by Maxwell Stress Tensor (MST) on both sides of cell. DEP force is calculated by integrating electric stress on particle surface. In the present study calculated electric stresses is validated by DEP force calculated using EDM method and exact solution. we neglect other electrokinetic effects such as electrophoresis and electro-osmosis. Electrophoresis can be neglected if the particles are not charged. The effect of applied voltage, dielectric constants of cells and cells orientation on particle-particle interaction force has been studied.