Simulation and experiments of microelectrode geometry effects on dielectrophoretic particle collection in microfluidic devices

In a non-uniform electric field, particles show dielectrophoretic (DEP) behavior. This is a phenomenon where particles are attracted or repelled by the electric field depending on their electrical properties, size, the surrounding medium, and the frequency of the applied field. These effects are called positive or negative dielectrophoresis, corresponding to attraction toward or repulsion from the electrodes, respectively. With the right frequency, the particles can be manipulated, separated, or collected, based on their characteristics. We designed and simulated three types of electrodes: "fishbone," "snake," and "sine" structures, and integrated them into microfluidic channels. The electrodes were designed to direct the micron/submicron-sized particles by positive DEP force to the center of the channel, enabling their specific collection and concentration at the outlet. For comparison, we calculated the DEP force for each electrode design, and simulated the particle trajectories within the device. Additionally, we fabricated these devices and experimentally measured their particle collecting efficiency.