Numerical investigation of continuous acoustic particle separation using electrothermal pumping in a point of care microfluidic device

Abstract

Acoustic microfluidics has many advantages; however, the method has an integration limitation due to the pumping mechanism in which fluids could only be pumped using equipment which lays outside the whole system. This limits the footprint of the microfluidic network to have integrated devices. In this study, a new solver is developed in open-source code Open-FOAM to apply dielectrophoresis, electrothermal and standing-surface-acoustic-waves force to the fluid and particles. This study presents a novel pumping mechanism for acoustic microfluidics utilizing electrothermal force. The pumping section not only creates forward movement, but also focuses the particles in the middle of the micro-channel removing the need for a separate IDT module for particle focusing. The new configuration of electrodes increases fluid velocity up to 400% in comparison with conventional electrodes arrangement. The new configuration let 87% of particles to pass through the electrodes toward the outlet eliminating the problem in particle passage through the electrodes. The appropriate arrangement of the electrodes is also investigated for efficient particle movement in the micro-channel. In the acoustic separation, the power of 0.0015 W is considered efficient with a separation efficiency of 96% and purity of 94.1% for 10 micrometer and 95.9% for 5 micrometer polystyrene particles.