Barrier contactless dielectrophoresis: A new approach to particle separation

Barrier contactless dielectrophoresis is proposed as a method for microbiological particle separation. Design of a separation device for barrier contactless dielectrophoresis is discussed. The principle of separation device is based on formation of barriers of gradient fields in the volume of separation chamber by electrodes with passivation dielectric coating of silicon carbide. A feature of the method is absence of contact between separated samples and conductive elements of electrode structure. The proposed method is highly efficient and easy to use in comparison with dielectrophoresis on isolated structures and conventional planar systems. Computer simulation of electric field distribution over dielectrophoretic barriers is carried out, and effect of the thickness of the passivation coating on dielectrophoretic properties of barriers is shown. Forces acting on a particle (a yeast cell with a diameter of 7 μm) in separation chamber are evaluated using computer simulation data. Ability of the cell to be captured by the method of contactless barrier dielectrophoresis is theoretically predicted and confirmed experimentally, using yeast cells. The yeast cells subjected to positive dielectrophoresis can be effectively captured (up to 90%) by the separation device at the applied voltage of 20 V and 100 kHz and at flow rate of 20 mL/h.