Positioning of cells flowing in a fluidic channel by negative dielectrophoresis

Control of the flow position of cells in a microchannel is useful for developing cell separation systems. We demonstrated that cells with different sizes were transported through different gaps by a repulsive force generated by negative dielectrophoresis (n-DEP). A device was fabricated by sandwiching a polyester film with a fluidic channel between upper and lower substrates with design same as that of navigator and separator electrodes which were used to concentrate the flowing cells in the center of the channel and to guide them to gaps of different sizes, respectively. The performance of the system was assessed using a human acute monocytic leukemia cell line (THP-1) and red blood cells (RBCs) from preserved equine blood as model cells. The cells flowed along the edges of navigator electrodes to concentrate in the center of the channel because of a strong repulsive force between the upper and lower substrates induced by the application of an AC electric field. THP-1 and RBCs passed through gaps of different sizes in a separator consisting of a microelectrode array. Passage efficiencies for THP-1 and RBCs through the desired gaps were found to be 88% and 44%, respectively. The results indicate the possibility of the continuous separation of cells with different sizes in the fluidic device based on n-DEP.