Microparticle motion under dielectrophoresis: immersed boundary—Lattice Boltzmann-based multiphase model and experiments

This study investigates the electrokinetic manipulation of microparticles within microchannels under low Reynolds number (Stokes flow) conditions. We employed the immersed boundary-lattice Boltzmann method (IB-LBM) for multiphase simulations to analyze microparticle behavior in a Newtonian fluid under the influence of both hydrodynamic and external dielectrophoretic forces. To achieve this, we developed an in-house C-language code, establishing a hybrid setup wherein the external dielectrophoretic force is numerically computed using the finite-difference method (FDM). This force is then scaled through a mapping mechanism and integrated into the IB-LBM simulation. A series of benchmarking studies were conducted to validate the IB-LBM code by comparing our simulation results with existing analytical, numerical, and experimental data. In conjunction with the numerical work, we fabricated a microfluidic device in-house using standard lithographic techniques. Experiments were designed to replicate the conditions modeled numerically, using red blood cells as representative bioparticles. Our results demonstrate excellent agreement between numerical and experimental data for bioparticle trajectories within the microchannel under the influence of DEP forces in continuous-flow conditions and steady-state positions in the absence of flow, which opens up possibilities for broader applications in active-based microfluidic platforms.