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Novel Magnetic Nanoparticles for Medical Applications

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posted on 10.07.2018, 10:10 by Katie Dexter
The main purpose of this work was to investigate methods of producing nanoparticles with higher magnetic moments and saturation magnetisations than in current commercially available (Fe-oxide) nanoparticles. Such nanoparticles could be used to realise novel treatment of cancer, magnetic nanoparticle hyperthermia (MNH). These particles can also be optimized for use as magnetic resonance imaging (MRI) contrast agents and in a novel imaging system called magnetic particle imaging (MPI). It is advantageous to use pure Fe as the nanoparticle material as it has a much higher magnetisation than Fe-oxide, so these nanoparticles should perform better in MNH. In medical applications however, pure Fe needs to be encapsulated in a biocompatible shell, so high-performance nanoparticles need to be produced as core-shell particles. Here, data is presented from Fe@Cu, Fe@Ag, Fe@Al, Fe@Mg core-shell nanoparticles, and a set of pure Fe nanoparticles. Transmission electron microscopy (TEM) images were utilised for obtaining detailed nanoparticle size and shape distributions, and, specifically, were also analysed using a novel parameter: the geometry factor. The geometry factor is the ratio of the true area of the nanoparticle (in 2-D), divided by its maximum possible area if it were scaled to a sphere: a less subjective manner to judge particle shape than by eye. Composition analysis was performed using energy dispersive x-rays (EDX). The magnetic nature of our nanoparticles was investigated through magnetometry. Measurement of the magnetisation (M-H curves) enabled the magnetic moments of the samples to be determined. Our best performing nanoparticles were pure Fe with a saturation magnetisation higher than that of bulk pure Fe (0.220 Am2/g) of 0.262 ± 0.026 Am2/g at 300 K. These nanoparticles were produced at room temperature (21 ± 2 oC), a mean diameter of ~18 nm, and a geometry factor of ~0.8, indicating they are likely to contain mostly cuboctahedral shapes.

History

Supervisor(s)

Baker, Steve; Roy, Mervyn

Date of award

08/06/2018

Author affiliation

Department of Physics and Astronomy

Awarding institution

University of Leicester

Qualification level

Doctoral

Qualification name

PhD

Language

en

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