Fluorescent nanodiamonds: bioengineered functional materials

Day, Adam 2019. Fluorescent nanodiamonds: bioengineered functional materials. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

This thesis examines the development of tools which enable the production of functional hybrid materials utilising a synthetic biology derived structural component and a nanoparticle based functional component. These components were designed to be covalently linked with a produced ligase enzyme, Sortase A (SrtA). The functional component, nanodiamond (ND), a nanoparticle consisting of an sp3 carbon core and orthogonal surface was subjected to surface functionalisation using dispersions of surface polycarboxylated ND-COOH in aqueous and organic media via EDC/NHS mediated amidation. Due to the paucity of well-defined and characterised particles in the literature, initial methodology development in the production and characterisation of such surface functionalised species was demonstrated, investigating the functionalisation of ND-COOH with synthesised water soluble naphthalimide based and [Ru(bipy)3] based amine terminated luminophores Nap-1 and Ru-1 (respectively) and co-functionalisation of ND-COOH with both species (Chapter 2). From this development, ND suspension exhibiting green (Nap-1) and red (Ir-1, a synthesised iridium organometallic luminophore) emitting species and a SrtA enzyme tag were produced with the Nap-1/peptide ND species exhibiting demonstrable activity towards sortase modification. (Chapter 3) The biological structural component, E. coli biofilms presented here chiefly consist of, and rely on for their formation, curli fibrils primarily composed of amyloid structures of the protein CsgA. Through the incorporation of a developed plasmid, PFF753CcsgA (which harbours the csgA gene), into an engineered E. coli strain MG1655 ompR234 PRO ΔcsgA, a system demonstrating tight control (dependent on chemical induction) in CsgA production and biofilm formation was demonstrated. Induction E. coli strain carrying this plasmid resulted in a statistically verified increase in biofilm biomass, surface area, and thickness imaged through confocal fluorescence microscopy (CFM). Engineering of the CsgA protein to incorporate a sequence recognisable by the ligase SrtA at the C-terminus through resulted in abrogation of CsgA amyloid mediated biofilm formation. This was partially ameliorated through the incorporation of a flexible linker region between CsgA and the SrtA tag. (Chapter 4) Finally, from the development of the luminophore Nap-1 for ND attachment, a set of six bispicolylamine fluorescent ligands and their corresponding fac-[Re(CO)3Lx]BF4 complexes were synthesised and their photophysical properties characterised. The water-soluble Nap-1 derived ligand L5 was chosen for further work with the analogous Abstract II technetium complex with applications as a bimodal (optical/SPECT) imaging agent (Chapter 5).

Item Type:	Thesis (PhD)
Status:	Unpublished
Schools:	Chemistry
Date of First Compliant Deposit:	13 February 2020
Last Modified:	26 Mar 2021 16:14
URI:	https://orca.cardiff.ac.uk/id/eprint/129614

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