Chughtai, Muhammad Wajih Ud Din
(2022)
A Hybrid Microfluidic Chip with Multielectrode Geometry for Cell Concentration using AC pDEP and Multiwave ACEOF.
PhD thesis, University of Liverpool.
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Abstract
Microfluidic systems for cell concentration are becoming increasingly important tools in life science research and diagnostics. The ability to handle life cells in a highly controlled environment offers opportunities to automate complex procedure such as IVF, liquid biopsy, and single-cell isolation. Despite promising applications, present-day cell isolation techniques, either lag efficiency or deal with specific cells only. On the other hand, AC Electroosmotic flow (ACEOF) apply force on fluid medium only and therefore does not rely on cell properties. From this point of view, AC EOF is an exciting alternative for current cell concentration techniques. This research combines two AC Electrokinetic phenomena, namely AC positive dielectrophoresis (AC pDEP) and AC Electroosmotic flow (ACEOF), to build a microfluidic device that is capable of providing a cell concentration factor of 100000/mL at the flow rate of 45μL/min. To achieve this goal, firstly, AC pDEP and ACEOF response are thoroughly examined against the parameters such as electrode geometry, interelectrode gap, fluid conductivity, chamber height, AC signal strength and frequency, and it is established that 75μm interelectrode gap provide an ACEOF vortex size of 430μm at 10Vpp, 1kHz for the fluid conductivity of 10mS/m while 100μm interelectrode gap provides a vortex size of 290μm for the same parameters. On the other hand, 20Vpp, 1MHz provides AC pDEP efficiency of ~50% at 300μm chamber height for a pair of electrodes. Based on these results, a microfluidic device is built with ten individually addressable electrodes, which offers an AC pDEP efficiency of >95% at 45μl/min flow rate, with overall ACEOF yield of >90% and an concentration factor of 100000 using 2000s AC pDEP and five waves of ACEOF. In the end, results of both AC pDEP and ACEOF are validated using finite element modelling that also provides a model for multi-vortex ACEOF.
| Item Type: | Thesis (PhD) |
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| Divisions: | Faculty of Science and Engineering > School of Electrical Engineering, Electronics and Computer Science |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 13 May 2022 18:42 |
| Last Modified: | 18 Jan 2023 21:06 |
| DOI: | 10.17638/03151638 |
| Supervisors: |
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| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3151638 |
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