Computational nano-materials and catalysis: Modelling of structural and magnetic properties of bare and ligand-protected cobalt nanoparticles

Farkas, Barbara 2021. Computational nano-materials and catalysis: Modelling of structural and magnetic properties of bare and ligand-protected cobalt nanoparticles. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Up to now, cancer treatments have been based on the combination of chemotherapy and radiation, which are on a day-to-day basis experiencing a rise of serious risks as many tumour types are developing specific refractory mechanisms. For cancer patients, these so-called ’side effects’ can seem to take over daily life or seriously contribute to the deterioration of their medical condition. Recently, hyperthermia directed specifically to cancer cells through the use of relaxation mechanisms of magnetic nanoparticles resulted in the localised heat generation and showed a promising shift in reducing the share of healthy areas exposed to the treatment sources. Although magnetic nanoparticle hyperthermia has imposed many challenges and requirements and is still a highly experimental cancer treatment, new research shows that the therapy is, in fact, clinically effective. Given the overall goal of generating the heat locally within the tumour, the primary objective of the therapy is in the nanoparticle design - maximising the power deposition. Nanoparticles that are most easily adjusted in vivo and have the best biocompatibility (magnetic oxides), however, are not necessarily the ones that provide the greatest heating effects. The effectiveness of the therapy, as well as its possible adverse effects, depend on a number of physiochemical characteristics of the nanoparticles, such as chemical composition, size, shape, as well as on their magnetic behaviour. With the highest magnetisation of transition metals and most metal oxides, cobalt is offering a promising power dissipation within the size limitations of the cancer diagnostic and treatments therapies. The aim of this thesis is to investigate theoretically, by means of density functional theory and ab initio molecular dynamics and metadynamics, some of the current challenges in employing cobalt nanoparticles as biomedical agents. In particular, the focus will be on the physical and magnetic properties that are related to the imaging and heating efficiency, by unfolding the connection between the size, structure, reactivity, and magnetic behaviour as the most important relationship towards making reliable predictions on the dependence of desired properties on nanoparticle morphology. Coating and alloying effects will also be contemplated as changes in the magnetic behaviour can be induced by an active interplay between the surfactants and nanoparticle or between different metallic phases. This constitutes a necessary gateway before attempting a rational, engineered tuning of the magnetisation of cobalt nanoparticles for real-life applications. The idea is to build a sound model for further theoretical simulations on magnetic nanoparticles, and to provide experimentalists with useful guidelines for the design of magnetic nanocomposites with improved hyperthermia efficiencies.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Chemistry
Funders:	EPSRC
Date of First Compliant Deposit:	23 September 2021
Last Modified:	04 Mar 2023 02:41
URI:	https://orca.cardiff.ac.uk/id/eprint/144401

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