Numerical Study of Acoustophoretic and Thermophoretic Aggregation of Micro- and Nano-Sized Particles
type: CreativeWork
description: Precise manipulation of bio-micro/nanoparticles, including cells, platelets, bacteria, and extracellular vesicles, is critical for tumour diagnostics, infectious disease detection, and cell analysis. The acoustofluidic aggregation method shows its significant advantages in microparticle aggregation, including highly scalable, label-free, contact-free, biocompatible and non-invasive. For nanoparticle enrichment, thermophoresis has been recently proposed as an efficient way to accumulate nanovesicles in biomedical applications. Although numerous experimental and analytical studies have been undertaken to study the micro/nanoparticle aggregation mechanisms, few studies have been conducted to optimise the acoustophoresis or thermophoresis device design. Therefore, this dissertation aims to improve the efficiency and accuracy of the micro/nanoparticle aggregation devices through numerical modelling using the finite element method. This research first conducts a numerical investigation of the acoustophoresis of microparticles suspended in a compressible liquid. The wall of the rectangular microchannel is made of Polydimethylsiloxane (PDMS), and Standing Surface Acoustic Waves (SSAW) are introduced into the channel from the bottom wall. The relative amplitude of the acoustic radiation force and the viscous drag force is evaluated for particles of different radii ranging from 0.1μm to 15μm. Only when the particle size is larger than a critical value can the particles accumulate at acoustic pressure nodes (PNs). While the displacement amplitude of SSAW impacts the time scale of particle movement, it does not influence the final position of the particles. The efficiency of the particle accumulation depends on the microchannel height, so an extensive parametric study is then undertaken to identify the optimum microchannel height. The optimum height, when normalised by the acoustic wavelength, is found to be between 0.57-0.82. Second, a numerical model is established to investi…
abstract: Precise manipulation of bio-micro/nanoparticles, including cells, platelets, bacteria, and extracellular vesicles, is critical for tumour diagnostics, infectious disease detection, and cell analysis. The acoustofluidic aggregation method shows its significant advantages in microparticle aggregation, including highly scalable, label-free, contact-free, biocompatible and non-invasive. For nanoparticle enrichment, thermophoresis has been recently proposed as an efficient way to accumulate nanovesicles in biomedical applications. Although numerous experimental and analytical studies have been undertaken to study the micro/nanoparticle aggregation mechanisms, few studies have been conducted to optimise the acoustophoresis or thermophoresis device design. Therefore, this dissertation aims to improve the efficiency and accuracy of the micro/nanoparticle aggregation devices through numerical modelling using the finite element method. This research first conducts a numerical investigation of the acoustophoresis of microparticles suspended in a compressible liquid. The wall of the rectangular microchannel is made of Polydimethylsiloxane (PDMS), and Standing Surface Acoustic Waves (SSAW) are introduced into the channel from the bottom wall. The relative amplitude of the acoustic radiation force and the viscous drag force is evaluated for particles of different radii ranging from 0.1μm to 15μm. Only when the particle size is larger than a critical value can the particles accumulate at acoustic pressure nodes (PNs). While the displacement amplitude of SSAW impacts the time scale of particle movement, it does not influence the final position of the particles. The efficiency of the particle accumulation depends on the microchannel height, so an extensive parametric study is then undertaken to identify the optimum microchannel height. The optimum height, when normalised by the acoustic wavelength, is found to be between 0.57-0.82. Second, a numerical model is established to investi…
author: Dong, Jing
language: eng
keywords: Acoustophoresis, Microparticles, Nanoparticles, Particle aggregation, Thermoacoustic streaming, Thermophoresis
license: https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/4c9dfa70-a557-4e0a-8378-191085d2c2d0/download
license: https://www.rioxx.net/licenses/all-rights-reserved/
date published: 2023-09-23
date modified: 2026-07-22T22:24:14Z
provider: Cambridge University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Cambridge

PropertyValue
property ID: DOI
value: 10.17863/CAM.107025