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Development of Graphene Based Biosensors for Early Detection of Alzheimer's Disease / HINA ABBASI

Swansea University Author: HINA ABBASI

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DOI (Published version): 10.23889/SUthesis.65090

Abstract

There has been extensive research on the electronic and physical properties of graphene since it was first discovered in 2004. This research has shown graphene to be a wonder material and makes it an ideal candidate for use in next-generation sensor technologies. Graphene consists of a single atomic...

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Published: Swansea, Wales, UK 2023
Institution: Swansea University
Degree level: Doctoral
Degree name: Ph.D
Supervisor: Guy, Owen J.
URI: https://cronfa.swan.ac.uk/Record/cronfa65090
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Abstract: There has been extensive research on the electronic and physical properties of graphene since it was first discovered in 2004. This research has shown graphene to be a wonder material and makes it an ideal candidate for use in next-generation sensor technologies. Graphene consists of a single atomic layer of sp2 hybridized carbon atoms and has exceptionally ballistic electronic transport, alongside high specific surface area, strong mechanical strength, and flexibility, which is essential for constructing biosensor devices. This thesis describes the development of graphene-based biosensors for the early diagnosis of Alzheimer’s disease (AD). For that purpose, this work was focused on developing novel functionalization chemistries for the attachment of bioreceptors to graphene and subsequent detection of AD biomarkers. Three different functionalization mechanisms i.e., diazonium grafting, pDAN electropolymerization, and neutravidin protein attachment were studied and explored in detail. Amongst them, the pDAN electropolymerization, and neutravidin protein attachment methods were utilized for graphene surface functionalization and successful development of biosensors for the detection of three biomarkers i.e., Aβ(1-40), Aβ(1-42), and Tau-352 that have been reported as potential candidate biomarkers for AD. The lowest limit of detection for all three biomarkers was observed when using the neutravidin protein attachment method on rGO-modified screen printed electrodes. The proposed approach showed a wide logarithmically linear range of detection from 10 fg/mL to 10 ng/mL in both diluted human plasma as well as phosphate-buffered saline (PBS) solutions. The fabricated sensors also showed stability of up to 6 weeks.The reported immunosensors can be utilized for the rapid screening of patients. In addition to that, the electrochemical sensing techniques used in this thesis are easily adaptable and hence can be miniaturized to develop portable and nonexpensive devices. These devices have the capability of performing rapid measurements on solutions with biomolecules even at very low concentrations. Hence, point-of-care monitoring and diagnostics can be performed using these devices.
Keywords: Nanotechnology, Electrochemical Biosensors, Graphene, Alzheimer’s Disease
College: Faculty of Science and Engineering
Funders: H2020 MSCA-ITN-ETN BBDiag project (grant number: 721281).