Dielectrophoretic behavior of a single cell when manipulated by optoelectronic tweezers: A study based on COMSOL ALE simulations

• The movement of a single cell has been studied using both ALE and particl tracing method on the COMSOL.
• The ALE and particle tracing method adopt Maxwell stress tensor and dipole polarization moment, respectively.
• The ALE method has the more accurate estimations than that of the particle tracing method.

Optoelectronic tweezers uses optically induced dielectrophoretic (DEP) force for manipulating cells in aqueous solution, which has shown potential applications in biology and tissue engineering among other possibilities. To effectively design the optoelectronic tweezers (OETs) chip, detailed knowledge about the behavior of cells in response to DEP force in an aqueous layer is needed. In this paper, the trajectories of an SMMC-77721 cell, simulated as a rigid dielectric sphere, in the induced electric field of optical trapping are studied using both an Arbitrary Lagrangian-Eulerian (ALE) method and a particle-tracing method (PTM) available within the COMSOL multiphysics software platform. Because the ALE method involves solving the distorted electric field around the cell and taking a full account of the Maxwell stress tensor (MST), it is expected to provide more accurate predictions about the spherical cell velocity than PTM that involves dipole moment approximation. Our ALE results show noticeably greater cell velocity than that predicted by the classical DEP expression based on dipole moment approximation. The ALE model can help gain new insights for analyzing cell motions in aqueous solution under sophisticated optical spot patterns.