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Acoustofluidic manipulation of cells

Wu, Fangda 2021. Acoustofluidic manipulation of cells. PhD Thesis, Cardiff University.
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This thesis aims to investigate the manipulation of cells, especially cancer cells, via acoustofluidic techniques at high ultrasound frequencies. This PhD project's motivation and ultimate goal are to separate circulating tumour cells (CTCs) from normal blood cells to achieve CTCs detection via acoustofluidic techniques. At the same time, the acoustofluidics-based manipulation of other types of cells and microparticles have also been investigated. The presence of rare cancer cells in cancer patient blood, called CTCs, has been increasingly researched as an essential biomarker for cancer diagnosis and cancer treatment monitoring. Separation and enrichment of CTCs from cancer patients’ blood samples via liquid biopsy methods have shown excellent compatibility compared with the conventional screening and invasive tissue biopsy methods. As a novel, bio�compatible and label-free technique, acoustofluidics has the potential to become an effective tool to sort CTCs from liquid samples or manipulate other types of cells via the cells physical properties: size, density, and compressibility. In this thesis, acoustofluidic platforms based on standing surface acoustic waves (SSAW) are demonstrated, including the Interdigital transducers (IDTs) design, cleanroom (CR) fabrication, and integration with microfluidics, electronics and mechanics systems. The simulation has been conducted via Governing equations (Continuity and Navier-Stokes equation) and Finite Element Method (FEM) model to understand the working principle and compare it with the microparticles manipulation experiment on the parallel and tilted-angle IDT SSAW devices. Moreover, a conventional tilted-angle (CTA) IDTs acoustofluidic device has been applied to wash the electroporated cells from the original medium, and a higher electroporation efficiency and cell viability are achieved. By optimising the IDTs patterning, a filled tilted-angle (FTA) IDTs design with less electrical input power but higher acoustic energy generated compared with CTA IDTs is demonstrated that achieves around 90% deflection efficiency of Hela cells with the input power of 4.5 W. In addition, to overcome the challenges of frangibility and overheating due to the conventional SSAW substrates, a novel Gallium Nitride (GaN) compound semiconductor film based acoustic tweezer is demonstrated. Cancer cell patterning via the GaN platform has been successfully achieved with excellent thermal stability with high input power. SSAW-based acoustofluidic cell manipulation in this thesis extends understanding of acoustofluidics techniques via the novel IDT design and SSAW generation substrate and will enable further development in high precision cell manipulation and biosensors applications

Item Type: Thesis (PhD)
Date Type: Completion
Status: Unpublished
Schools: Engineering
Uncontrolled Keywords: Acoustofluidics , Surface acoustic wave (SAW) , Lab on chip , Circulating tumour cell (CTC) , Acoustic tweezer
Date of First Compliant Deposit: 28 April 2022
Last Modified: 14 Dec 2022 02:26

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