Influence of the obstacles on dielectrophoresis-assisted separation in microfluidic devices for cancerous cells

Abstract

The development of a separation lab-on-a-chip device based on the particle size is critical in the early detection of circulating tumor cells. In this work, combining alternating current dielectrophoresis and drag force are used to precisely separate MDA-MB231 and red blood cells in the microfluidic platform. Four microfluidic devices with sidewall electrodes and different obstacle shapes were employed to both generate non-uniform fields inside the channels and condense the particles near the electrodes. Besides that, dividing the particles inlet into two main channels enable fast and accurate separation inside the device, and then particles deflected to the different outlets. Choosing the frequency is critical in the magnitude and sign of the dielectrophoresis force. Negative dielectrophoresis force was acting on both cancerous and red blood cells when the frequency was 10 kHz. Finite element simulation was conducted to predict the particle trajectories and revealed that the device with rectangular obstacles had the higher electric field non-uniformity when the voltage applied was set to 6 V and − 6 with the frequency of 10 kHz, Simulation represented 100% separation efficiency and purity for cancerous cells in the specific outlets. Decreasing the voltage from 6 V and − 6 V to 5 V and − 5 V could reduce the separation efficiency to 46%. The appropriate value of voltage (6 V, − 6 V) was applied to the electrodes resulting in the lower Joule heating and sufficient dielectrophoresis forces.