Download files
Abstract
Iron oxide nanoparticles (IONPs) have garnered a lot of interest in recent years due to their inherent biocompatibility and unique magnetic properties. These characteristics give the particles strong potential in biomedical applications such as MRI contrast agents and in tumour therapy. Nude particles however are unstable in biological environments, and undergo rapid agglomeration due to the presence of high salt concentrations, adsorption of proteins, and removal via the immune and renal systems. This leads to the loss of the properties unique to nanoparticles and reduced efficacy in the body. In order to prevent this from occurring, biocompatible polymers can be attached to the surface of the particles in order to provide steric stability and stealth characteristics to the particles.
In this body of work, we explored novel approaches to the attachment of poly(ethylene glycol) based polymers to the surface of iron oxide nanoparticles. Using functional end groups of the polymers synthesised via reversible addition fragmentation chain transfer polymerisation, we investigated the novel application of thiol click chemistry for the attachment of polymers to the surface of the particles. Thiol groups are highly reactive towards isocyanate, epoxide and acrylate groups. The reaction between the respective groups facilitated simple method of synthesising polymer coated nanoparticles. In order to improve the stability of polymer coated IONPs, the use of a copolymer which incorporated active ester units was investigated. The active ester units are highly reactive towards primary amines, and a diamine crosslinker was used to crosslink the polymers on the particle surface. We analysed the stability of the particles after crosslinking and found there was an improvement in the stability of the particles in water.