Comparison of computational methods for the estimation of the dielectrophoretic force acting on biological cells and aggregates in silicon labonchip

Dielectrophoresis (DEP) is a promising method for particles manipulation without physical contact in silicon lab-on-chip devices. It exploits the dielectric properties of cells and aggregates suspended in a microfluidic sample under the action of high-gradient electric fields. The force is approximated by a truncation of a multipole expansion which, for single cell, reduces to the first order contribution. When the cells aggregate is “big” further terms should be considered involving higher order field derivatives. Here, we compare different force approximations, depending on the aggregate's dimension and on the non-uniformity of the electric field. Numerical modeling has been performed by using COMSOL Multiphysics to compute the electric field, to quantify the DEP forces and to simulate the particles tracings that have been compared with experimental results developed in several settings.