Numerical simulation of cell stirring and separation in a micro droplet using surface acoustic wave-driven flow

Abstract

Flow generation techniques using surface acoustic wave (SAW) have been developed. This technique is useful for the mixing/separation of particles in a small droplet and can be applied for the laboratory testing with extremely small amount of specimen. In this study, a hemispherical shaped micro water droplet with a volume of 30 μL was modeled and the SAW-driven flow in the droplet was numerically calculated. The calculation results show that a vortex generated around the SAW irradiation site moves toward the droplet center and it derives upward flow. The particles with the same degree as the density of water follows the flow field in the droplet and eventually pile on the peripheral area. The particles with high density moves toward the droplet center along the substrate surface and accumulate at the central area. The feasibility of cell separation was confirmed from the numerical simulation.