Synthetic Routes to Greener Pastures: A Sustainable View Towards Biomedically Relevant Magnetic Nanomaterials

Abstract

Magnetic nanomaterials such as the spinel-type oxides, MFe2O4 (M = Fe2+, Co2+, Ni2+, Zn2+) have emerged as key materials in nanomedicine, with highly tuneable properties, accessed by varying composition or surface modification with functional ligands. Their biomedical applications, such as magnetic hyperthermia; an adjuvant to cancer therapies, require the nanoparticles to be water-dispersible, biocompatible, and possess sufficiently high magnetic saturation. As such, control of these properties is essential in the synthesis of these materials. While there are many examples in the literature of ways to obtain iron oxide nanoparticles, there is a happy medium between synthetic control and sustainability that has not yet been realised by any one technique in particular. The present work aims to provide a comparative study of some of the most commonly employed synthetic techniques for producing nanoparticles for this application; including thermolysis or batch heat-up vs. hot injection, batch hydrothermal methods, and the use of a novel, custom-built hydrothermal injection reactor aiming to combine the green sensibilities of hydrothermal processing, with the synthetic control of the popular hot injection method. This thesis showcases the capabilities of each of these methods in targeting biomedically relevant magnetic nanomaterials, both of different morphologies and size regimes, while summarising their advantages and disadvantages from a sustainable perspective. This work also includes the use of sol-gel combustion methods to access related materials, for the purposes of introducing the fascinating properties of magnetic nanomaterials to a wider audience. Overall, this work aims to shed light on more sustainable routes to magnetic nanomaterials with suitable properties for use in medicine; promoting the use of greener chemistry in a rapidly expanding field.