Dependence of acoustophoretic aggregation on the impedance of microchannel's walls
Year: 2024
Type: article
Abstract: • A full cross-sectional model of the acoustofluidic device is developed using finite element method. • Influences of the acoustic properties of the fluid and the microchannel wall on SSAW-based acoustophoresis are systematically investigated. • An order-of-magnitude enhancement in acoustic pressure and a significant reduction in particle threshold size are achieved through properly adjusting channel dimensions and acoustic impedance mismatch between the microchannel wall and the fluid. • Particle motions and terminal positions are visualized and analyzed. Acoustofluidic manipulation of particles and biological cells has been widely applied in various biomedical and engineering applications, including effective separation of cancer cell, point-of-care diagnosis, and cell patterning for tissue engineering. It is often implemented within a polydimethylsiloxane (PDMS) microchannel, where standing surface acoustic waves (SSAW) are generated by sending two counter-propagating ultrasonic waves on a piezoelectric substrate. In this paper, we develop a full cross-sectional model of the acoustofluidic device using finite element method, simulating the wave excitation on the substrate and wave propagation in both the fluid and the microchannel wall. This model allows us to carry out extensive parametric analyses concerning the acoustic properties of the fluid and the microchannel wall, as well as the dimensions of the channel, to explore their influences on the acoustic field, fluid flow and microparticle aggregation. Our findings demonstrate an order-of-magnitude enhancement in acoustic pressure amplitude and aggregation speed and a reduction in the particle threshold radius to submicron levels, which can be achieved through adjustments to the channel height and the difference in acoustic impedance between the channel wall and the fluid. The optimum channel heights are determined, which depend on the acoustic properties of the channel wall. The particle trajectories, movements along pressure nodal planes, and terminal positions are identified, with relative strength between the radiation force and the streaming force compared in different combinations of parameters. This work demonstrates that finetuning the dimensions and acoustic properties of the fluid and microchannel wall in acoustofluidic device can greatly enhance particle aggregation throughput and reduce constraints on particle size. Our findings offer valuable insights into device design and optimization.
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $2,880
OpenAlex ID: W4404800964