Year

2018

Degree Name

Doctor of Philosophy

Department

Institute for Superconducting and Electronic Materials

Abstract

The field of nanotechnology has given rise to advancements that continue to positively impact our quality of life in a variety of different ways, in none more so than in the fields of healthcare and medicine. Recent years have seen significant research effort into the development of new techniques and materials, with the aim to form the basis of diagnostic and therapeutic strategies in order to treat disease and injury more efficiently and effectively. This has already resulted in a number of different ’nanomedicines’ approved for prescription and use in products both in Australia and abroad, with an increasing number undergoing clinical trials each year. Such agents have been tailored on the nano-scale to possess superior qualities than their ’bulk’ counterparts, whether it be through improved targeting, selectivity, or efficiency in order to improve patient outcomes. One such example, one which as Australians has significant importance to us, is the use of metal oxide nanoparticles within topical sunscreen and cosmetic products in order to reduce our exposure to ultraviolet light and hence minimise the risk of developing skin cancers and the other negative consequences of this exposure, such as skin aging and immunosuppression. Currently, ZnO and TiO2 nanoparticles are used in this application, due to their low cost and optical properties, which are superior to their microsized counterparts. Some of nanoparticles have the potential to act as potent photocatalysts and have shown to have the capacity to degrade the other organic components of the sunscreen formulations, decreasing their efficiency. There has been a plethora of studies which suggest that such particles are not able to penetrate through the upper layer of skin to reach the underlying viable skin cells, but inconsistencies in some of these results, small sample sizes, and many not investigating the influence of ultraviolet light still poses some questions. As such, there has been some research interest into the investigation of alternatives metal oxide nanoparticles with similar efficiency of UV-absorption with complementary properties. Given that free radicals have consequence to some of the organic photochemistry resulting from organic ultraviolet filters decomposing, nanoparticles with free radical scavenging properties with high ultraviolet absorption such as CeO2 have been proposed in the past. These nanoparticles with free radical scavenging properties have also been proposed as the basis of therapeutic agents, as free radicals play important functions within human health. Exposure to ionising radiation, drugs, environmental contaminants can result in a state of increased free radical species, and if this is more than the body is able to neutralise with antioxidants, this is known as oxidative stress. Oxidative stress phenomena also plays a role in a large number of diseases including cancers, neurodegenerative diseases, autoimmune diseases, liver disease as well as in spinal chord injury. As such, these nanomaterials have the potential to be multifunctional, in the context of providing ultraviolet protection as well as protection from oxidative stress. In this thesis work, we investigate a number of iron oxide-based nanomaterials targeted toward application in these two areas.

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