Interdigitated electrode design and optimization for dielectrophoresis cell separation actuators

Among all particle separation approaches, dielectrophoresis actuators which use electric properties difference between particles, have turned into strong separating tools. This way, the particles in the fluid within non-uniform electric field experience the dielectrophoresis force. The amount and direction of this force depend on the fluid and particle polarization, particle size and electric field gradient. In this paper after presenting governing equations concerning the dielectrophoresis phenomenon, a microfluidic actuator introduced in which an interdigitated electrode pattern is applied in. Voltage, pitch, and width to pitch ratio of electrode as well as channel height are of the most important geometrical parameters of this actuator whose individual effect on particles separation was investigated using finite element analysis (FEM). The simulation results showed that if the actuator is intended to work in the efficient conditions, channel height and electrodes pitch should be near to each other, height needs to be as minimum as possible while voltage as maximum as possible in order to reach to the least time duration and the highest quantity for particles separation. Then, using theoretical equations and simulation results, a flowchart is introduced to design and optimize dielectrophoresis separation actuators. Finally, experimental results for k562 cell separation, as a biological particle, from Polystyrene, as a standard particle, is presented. In the fabricated actuator recovery and purity efficiency are 93% and about 100% respectively.