Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Low-cost capacitive CMOS capacitive E. Coli biosensor for point-of-need water quality monitoring
Dissertation (MEng (Microelectronic Engineering))--University of Pretoria, 2023.
Saved in:
| Other Authors: | |
|---|---|
| Format: | Thesis |
| Language: | English |
| Published: |
University of Pretoria
2023
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613675796299776 |
|---|---|
| access_status_str | Open Access |
| author2 | Joubert, Trudi-Heleen |
| author_browse | Joubert, Trudi-Heleen |
| author_facet | Joubert, Trudi-Heleen |
| collection | Thesis |
| dc_rights_str_mv | © 2023 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MEng (Microelectronic Engineering))--University of Pretoria, 2023. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/93825 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:39:55.528Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/93825 Low-cost capacitive CMOS capacitive E. Coli biosensor for point-of-need water quality monitoring Joubert, Trudi-Heleen george.andrews@tuks.co.za Andrews, George UCTD Capacitive biosensing Lab-on-chip Water quality monitoring CMOS E. Coli Sustainable Development Goals (SDGs) Engineering, built environment and information technology theses SDG-06 SDG-06: Clean water and sanitation Dissertation (MEng (Microelectronic Engineering))--University of Pretoria, 2023. Exposure to pathogenic Escherichia coli (E. coli) bacteria through contaminated water can cause potentially life-threatening diarrhea and vomiting, and it is a useful water quality indicator. Simulations and experiments are conducted to give guidelines on low-cost capacitive biosensing devices aimed at bacterial sensing, and a custom integrated circuit that can be used in a low-cost capacitive biosensing device is delivered. Finite element modelling was conducted to compare the electric fields (E-fields) and capacitance across different electrode geometries and materials. The size of electrode features had the biggest impact on electric field strength and relative capacitance change in the presence of cell-like structures. The simulation results are used to clarify assumptions on how simulations for the design of capacitive sensing electrodes need to be conducted. Capacitance measurement of low-cost and commercial electrodes was conducted using a benchtop LCR meter and 3 μm microbeads as substitutes for E. coli cells. It was found that the measured capacitance increases as the concentration of microbeads increases, and the low-cost electrodes seem to show a higher-than-expected sensitivity when compared to commercial electrodes with smaller feature sizes. Electric impedance spectroscopy experiments conducted on E. coli cells showed a similar performance as characterisation experiments using microbeads. These insights inform the development of guidelines that may be used to design low-cost electrodes for similar applications. A custom integrated circuit (IC) featuring a capacitive sensing array with sub-surface electrodes was designed and delivered. This IC also includes the custom operational amplifier used in the sensing array, used in a low-cost capacitive biosensor prototype for point-of-need use. The low-cost device was characterised with 3 μm microbeads using a subset of the electrodes used in the LCR experiments, with comparable results achieved using the low-cost device. Lessons learned in the design of the low-cost system guide the development of a design flow for the design of point-of-need water quality monitoring devices and gives guidance on the required hardware to build such devices. NRF Grant IRG105878 Electrical, Electronic and Computer Engineering MEng (Microelectronic Engineering) Unrestricted Faculty of Engineering, Built Environment and Information Technology 2023-12-19T12:28:35Z 2023-12-19T12:28:35Z 2024-04 2023 Dissertation * A2024 http://hdl.handle.net/2263/93825 en © 2023 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Capacitive biosensing Lab-on-chip Water quality monitoring CMOS E. Coli Sustainable Development Goals (SDGs) Engineering, built environment and information technology theses SDG-06 SDG-06: Clean water and sanitation Low-cost capacitive CMOS capacitive E. Coli biosensor for point-of-need water quality monitoring |
| title | Low-cost capacitive CMOS capacitive E. Coli biosensor for point-of-need water quality monitoring |
| title_full | Low-cost capacitive CMOS capacitive E. Coli biosensor for point-of-need water quality monitoring |
| title_fullStr | Low-cost capacitive CMOS capacitive E. Coli biosensor for point-of-need water quality monitoring |
| title_full_unstemmed | Low-cost capacitive CMOS capacitive E. Coli biosensor for point-of-need water quality monitoring |
| title_short | Low-cost capacitive CMOS capacitive E. Coli biosensor for point-of-need water quality monitoring |
| title_sort | low cost capacitive cmos capacitive e coli biosensor for point of need water quality monitoring |
| topic | UCTD Capacitive biosensing Lab-on-chip Water quality monitoring CMOS E. Coli Sustainable Development Goals (SDGs) Engineering, built environment and information technology theses SDG-06 SDG-06: Clean water and sanitation |
| url | http://hdl.handle.net/2263/93825 |