Dielectrophoretic Separation of Healthy and Infected Red Blood Cells through Electric Driven Flow: An Electrokinetic Modeling

This paper presents a novel approach to insulating dielectrophoretic cell sorting using electrokinetic modeling of electric driven bio-particle movements in micro-channel. We report a microfluidic device capable of separating healthy red blood cells (RBCs) and RBCs infected in vitro by parasites based on the competitive application of dielectrophoretic, electrophoretic, electro-osmotic, and drag forces acting on cells. After validation of numerical results with respective experimental data, a particle sorting model was developed to evaluate the effect of channel geometry, applied voltage, medium pH strength, and simultaneous dynamic effect of electric and flow fields. Computational investigations were performed based on the proposed model and the theoretical cell trajectory was calculated. Simulation results showed that RBCs with different dielectric responses perceived different dielectrophoretic force magnitudes while they were continuously pushed by electrophoretic effects and fluid drag force caused by electroosmotic flow over wall surface, and were therefore focused to different streamlines in microchannel. In addition, it was indicated that the pH of sample medium substantially influenced the zeta potential of RBCs and microchannel surface, which can widely change the electrokinetic movement of cells. Results also showed that a perfect separation can be achieved with the pH of 5 and applied DC voltage of 15 V.