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The optimisation of a nanofiber-based biosensor for the detection of targeted analytes
Thesis (PhD)--Stellenbosch University, 2024.
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867613882086850560 |
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| access_status_str | Open Access |
| author | Lloyd, Alexander Michael |
| author2 | Perold, W. J. |
| author_browse | Lloyd, Alexander Michael Perold, W. J. |
| author_facet | Perold, W. J. Lloyd, Alexander Michael |
| author_sort | Lloyd, Alexander Michael |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description |
Thesis (PhD)--Stellenbosch University, 2024. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/131801 |
| institution | Stellenbosch University (South Africa) |
| last_indexed | 2026-06-10T12:43:11.727Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/131801 The optimisation of a nanofiber-based biosensor for the detection of targeted analytes Lloyd, Alexander Michael Perold, W. J. Fourie, P. R. Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. Transducers, Biomedical Biosensors Electrochemical sensors Electrospinning Nanomedicine Drug resistance UCTD Thesis (PhD)--Stellenbosch University, 2024. ENGLISH ABSTRACTS: Antimicrobial resistance (AMR) represents a swiftly growing threat to public health care, globally. While the spread of AMR can be curbed by ensuring responsible and appropriate antimicrobial usage, this avenue is viable only if the necessary diagnostic information is available. Such a diagnostic device must be accurate, rapid, sensitive and affordable. To realise the potential of a biosensor fit for this purpose, an existing sensor production process was optimised. A custom electrospinning setup was developed that focused on producing nanofiber-based transducers repeatably, by implementing both a multi-needle array and lateral translation of the needles by means of a custom stage. This novel setup was also tailored to high throughput to decrease the overall sensor production cost. The polymer blend, consisting of polyvinyl alcohol (PVA), polyethylene oxide (PEO), poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and Dimethylformamide (DMF), was optimised so that the produced transducers were highly conductive. Alternative transducer configurations were investigated and custom rigid electrodes made from gold on FR-4 substrate were selected for development, as they significantly reduced sensor production cost when compared to alternatives. Multiple functionalisation methods were investigated, with streptavidin being the selected method. Once functionalised, novel sensors were developed from the transducers by binding antibodies targeted to C-reactive protein (CRP) to them. Using Electrochemical Impedance Spectroscopy, which was selected as the electroanalytical method, it was found that the produced sensors generated a measurable electrochemical response when the relevant targeted analyte is present in the solution. A response profile was developed, relating a percentage-wise increase in impedance to increasing target concentration. Thereafter, a model was fitted to the data that could be used to determine unknown concentrations of CRP in samples. The sensors are very sensitive to low concentrations of CRP, cheap to produce, and can provide results rapidly. AFRIKAANSE OPSOMMING: Antimikrobiese weerstand (AMW) word toenemend ’n ernstige bedreiging vir openbare gesondheidsorg, wˆereldwyd. Alhoewel die verspreiding van AWR bekamp kan word deur te verseker dat antimikrobiese middels op ’n verantwoordelike en toepaslike wyse gebruik geword, is hierdie opsie slegs lewensvatbaar indien die nodige diagnostiese inligting beskikbaar is. So ’n diagnostiese toestel moet akkuraat, vinnig, sensitief en bekostigbaar wees. Om die potensiaal van ’n biosensor, wat vir hierdie doel geskik is, te verwesenlik, is ’n bestaande sensorproduksieproses geoptimaliseer. ’n Pasgemaakte elektrospin-opset is ontwikkel, om nanovesel-gebaseerde transduktors te vervaardig op ‘n wyse wat herhaalbaarheid verseker. Met hierdie doel voor o¨e is daar ’n multi-naald-skikking en laterale translasie van die naalde deur middle van ’n pasgemaakte platform, implementeer. Hierdie nuwe opset is ook aangepas vir ho¨e deurset om die algehele sensorproduksiekoste te verlaag. Om te verseker dat die vervaardigde transduktors hoogs geleidend was, is die polimeermengsel, bestaande uit polivinielalkohol (PVA), poli¨etileenoksied (PEO), poli(3,4-etileendioksietiofeen) polistireensulfonaat (PEDOT:PSS) en Dimetielformamied (DMF), geoptimaliseer. Alternatiewe transduktorkonfigurasies is ondersoek en pasgemaakte rigiede elektrodes gemaak van goud op FR-4-substraat is gekies vir gebruik, aangesien dit sensorproduksiekoste aansienlik verminder het in vergelyking met alternatiewe opsies. Verskeie funksionaliseringsmetodes is oorweeg, en streptavidien is uiteindelik as die mees gepaste metode identifiseer. Sodra die transduktors gefunksionaliseer is, is die nuwe sensors vanaf die transduktors ontwikkel deur teenliggaampies wat op C-reaktiewe prote¨ıen (CRP) gerig is, daaraan te bind. Met behulp van Elektrochemiese Impedansie Spektroskopie, wat gekies is as die elektro-analitiese metode, is daar gevind dat die vervaardigde sensors ’n meetbare elektrochemiese respons gegenereer het wanneer die relevante geteikende analiet in die oplossing teenwoordig is. ’n Responsprofiel is ontwikkel wat ’n persentasiegewyse toename in impedansie in verband bring met toenemende teikenkonsentrasie. Daarna is ’n model by die data gepas wat gebruik kon word om onbekende konsentrasies van CRP in monsters vas te stel. Die sensors is hoogs sensitief vir lae konsentrasies CRP, goedkoop om te vervaardig en kan vining resultate lewer. Doctoral 2025-03-27T06:57:01Z 2025-03-27T06:57:01Z 2024-12 Thesis https://scholar.sun.ac.za/handle/10019.1/131801 Stellenbosch University 242 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Transducers, Biomedical Biosensors Electrochemical sensors Electrospinning Nanomedicine Drug resistance UCTD Lloyd, Alexander Michael The optimisation of a nanofiber-based biosensor for the detection of targeted analytes |
| title | The optimisation of a nanofiber-based biosensor for the detection of targeted analytes |
| title_full | The optimisation of a nanofiber-based biosensor for the detection of targeted analytes |
| title_fullStr | The optimisation of a nanofiber-based biosensor for the detection of targeted analytes |
| title_full_unstemmed | The optimisation of a nanofiber-based biosensor for the detection of targeted analytes |
| title_short | The optimisation of a nanofiber-based biosensor for the detection of targeted analytes |
| title_sort | optimisation of a nanofiber based biosensor for the detection of targeted analytes |
| topic | Transducers, Biomedical Biosensors Electrochemical sensors Electrospinning Nanomedicine Drug resistance UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/131801 |
| work_keys_str_mv | AT lloydalexandermichael theoptimisationofananofiberbasedbiosensorforthedetectionoftargetedanalytes AT lloydalexandermichael optimisationofananofiberbasedbiosensorforthedetectionoftargetedanalytes |