Engineering magnetic nanosystems for cancer diagnosis and treatment

Iron oxide magnetic nanocomposites can be used for a variety of biomedical applications, including magnetic resonance imaging (MRI) and as site specific drug delivery systems. By functionalising the surface of the nanocomposite, other functions like cell labelling and targeting can also be realised. Several iron oxide nanocomposites were prepared through microwave assisted co-precipitation reactions, using polyelectrolytes and dopamine as surface stabilisers. This provided a highly magnetic and versatile foundation that could be used immediately in biological applications (such as MR imaging) but could also be further functionalised extending the applications of the material. Functionalisation was achieved via electrostatic interactions and carbodiimide coupling which led to the development of a multifunctional nanocomposite capable of supporting both fluorescent and targeting groups.

This work demonstrates that the construction of the nanocomposite is key to unlocking the biomedical potential of the material. HRTEM and SQUID results demonstrate the importance of microwave irradiation in the formation of highly crystalline materials. Microwave heating enhances crystal growth which improves the magnetisation values of the composite, to beyond materials prepared by traditional co-precipition methods. Polyelectrolytes can bestow excellent water stability on the particles, with the composite remaining in sus- pension for over 8 weeks. MRI measurements show that the high magnetism, combined with excellent water stability, translates into an effective MRI contrast agent, with the prepared composite out performing other commercial agents. Further functionalisation with fluorescent groups show other applications in cell labelling, and the addition of targeting groups can further enhance the selectivity of the composite.

This work results in the development of a highly magnetic, extremely water stable iron oxide foundation, that can immediately be used as a MRI contrast agent and can support multiple functional groups like fluorescent dyes and targeting groups.