Simulation of Dielectrophoresis based Separation of Red Blood Cells (RBC) from Bacteria Cells

In this study, a microfluidic device was presented in which dielectrophoretic movement of red blood cell (RBC) and Clostridium difficile (C. difficile) bacteria with a diameter of 2.8 mu m and 1 mu m was studied. Simulation of the microfluidic device with sidewall electrodes was presented to produce a non-uniform electric field so that both positive dielectrophoresis (pDEP) and negative dielectrophoresis (nDEP) were observed at different frequency values. Particles affected by pDEP were attracted to the bottom side of the outlet channel, while those experiencing nDEP were repelled to the top side of the outlet depending on the polarity of the real part of Clausius-Mossotti factor. The influence of voltage, separation of electrodes, channel height, and radius of bacteria were also investigated for particle separation. In the simulation, the efficiency of RBC separation from C. difficile bacteria was as high as 99 % with an applied voltage of +/- 0.25 V at frequency 250 kHz and a flow rate of 6.05 mu L/s.