A High Frequency Dielectrophoresis Cytometer for Continuous Flow Biological Cells Refinement

This paper presents a microfluidic radiofrequency device operating at a few hundred MHz, which is able to sort biological cells. It uses a non-invasive and label-free technic based on intracellular dielectric specificities of biological cells. The sorting principle relies on a dynamic dielectrophoresis (DEP) deviation resulting from the interaction between a high frequency electric signal and the cell cytoplasm content. Driven in a microfluidic channel by a continuous flow, cells are individually deflected from their primary trajectories after having entered a non-uniform electric field generated by a microelectrode system. Designed with different slopes, these electrodes allow a selective guiding of cells to different outlets depending on the dielectrophoresis deviation efficiency. To allow a successful cell sorting, the intensity of deviation forces acting on cells is modulated according to the particle speed, the dielectrophoresis signal frequency and the electrode slope angles related to the Clausius-Mossotti factor of each cell. As proof of concept, experiments with cells from glioblastoma line were carried out, using different DEP signal frequencies to highlight system ability to sort cells from heterogeneous basal population into less disparate sub-populations.