Dependence of acoustophoretic aggregation on the impedance of microchannel's walls

Li, Yiming, Liang, Dongfang, Kabla, Alexandre, Zhang, Yuning, Ma, Jun and Yang, Xin ORCID: https://orcid.org/0000-0002-7612-614X 2025. Dependence of acoustophoretic aggregation on the impedance of microchannel's walls. Computer Methods and Programs in Biomedicine 260 , 108530. 10.1016/j.cmpb.2024.108530

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Abstract

Background and Objectives 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. Methods 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. Results 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. Conclusions 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.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Engineering
Publisher:	Elsevier
ISSN:	0169-2607
Date of First Compliant Deposit:	16 December 2024
Date of Acceptance:	25 November 2024
Last Modified:	16 Dec 2024 11:00
URI:	https://orca.cardiff.ac.uk/id/eprint/174708

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