Development of new DNA-binding sensitisers for biosensors

Judd-Cooper, Emily 2024. Development of new DNA-binding sensitisers for biosensors. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

This thesis describes efforts to develop cobalt complexes for use as DNA-binding sensitisers in biosensors for the detection of DNA. Exploration through biophysical and electrochemical studies provides an insight into the interactions and binding affinity of the cobalt complexes with dsDNA. The interaction with dsDNA is relevant because dsDNA is formed from a single-stranded capture strand and its target strand, if the target strand is present in a sample solution. Chapter two of this thesis covers efforts to improve upon the aqueous solubility of [Co(GA)2(aqphen)]Cl, a complex previously reported within the group. The core investigation involved the change of ancillary ligands on the cobalt(II) system to enhance aqueous solubility whilst retaining a strong binding affinity to DNA. The interactions and binding affinities of the cobalt(II) complexes with DNA were assessed through biophysical studies. Chapter three describes the synthesis of a series of cobalt(III) complexes, [Co(en)2(L)]3+, where L represents a dppz derivative, for the application as sensitisers for biosensors for DNA. This chapter centres on the interactions and binding affinities of cobalt(III) complexes with DNA using a range of biophysical techniques. Investigations into the variation of structural modifications of the dppz ligand were observed to influence the DNA-binding properties and aqueous solubilities. Finally, Chapter four of this thesis details investigations into the electrochemical behaviour of the cobalt(III) complexes outlined in Chapter three and their potential use as sensitisers in biosensors. The key investigation described in this chapter was the identification of the Co(III)/Co(II) redox couple to provide opportunities to use these complexes as sensitisers, exploiting electron paramagnetic resonance (EPR) as a potential electrochemical biosensor detection method. Through our collaborators at the University of Bath and within the Interdisciplinary Doctoral Training Hub (IDTH Biosensors and Diagnostics) at Cardiff University, the electrochemical behaviours of [Co(en)2(L)]3+ complexes with both DNA and endotoxin using electrochemical impedance spectroscopy (EIS) detection methods were studied.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Chemistry
Funders:	EPSRC
Date of First Compliant Deposit:	29 August 2024
Last Modified:	13 Sep 2024 09:04
URI:	https://orca.cardiff.ac.uk/id/eprint/171637

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