Isolated gold micro singularities for high density cell trapping based on dielectrophoresis

Dielectrophoresis (DEP) is broadly used in microfluidic systems for the cell therapies or medical diagnostics [1] because of its capability to handle and sort biological cells [2,3]. In this paper, a new method to trap cells on-chip with high density arraying capabilities is proposed. The principle is based on the use of metallic singularities arrayed within the flowing channel of the biochip. These singularities, even at a floating potential, induce a non uniform electrical field within the structure, responsible of a strong DEP force applied to cells. Indeed, we will demonstrate in the paper that metallic singularities generate stronger DEP forces, compared to more conventional methods where micro-dots of insulating material are arrayed to produce the electrical field traps. [4]. To the best of our knowledge, we report here the first successful use of such floating potential metallic singularities to trap cells. The main advantages of our method are: (i) the strength of the DEP forces that are generated by the metallic singularities, (ii) the capability to achieve high density trapping of cells as these singularities are not connected (iii) minimal perturbation of the cell flow when the polarization electrodes are not powered.