Synthesis and functionalisation of biocompatible magnetic nanomaterials

Abstract

The field of nanotechnologies for biological applications has recently experienced a rapid advance in the status of research. In particular, nanostructures have demonstrated their utility as a tool to obtain a direct interaction with cells. Applications of nanoparticles range from magnetic resonance imaging to drug delivery and hyperthermia treatments in which it is possible to act in a localised area of the body. In this thesis, we present a functionalization strategy that is sufficiently powerful to enable the use of highly ferromagnetic nanostructures in biological applications. We provide a protocol to prevent the aggregation of magnetic nanostructures such as nanoparticles and nanowires. The same protocol facilitates the nanostructure functionalization with molecules that make it possible to target and link biological structures for applications such as cell killing, cell separation or MRI contrast agent. Nanostructures of 2 different geometries (i.e. nanoparticles and nanowires) have been used, i.e. nanoparticles were used as a development model for the polymer stabilisation strategy used to stabilise nanowires. Up to 70 % of the nanoparticles could be individualised by poly(2-methacryloyloxyethil phosphorylcholine) coating, whereas most of the non-functionalised nanoparticles (≈60%) formed multiple clusters. Inclusion of clickable moieties in the polymeric corona made it possible to functionalise the nanoparticles surface with fluorescent dyes (≈ 4 dyes/nanoparticle). With this developed coating strategy it was possible to stabilise 2 different systems of nanostructures with non-spherical symmetry and higher magnetic moments. Additionally, this thesis work produced a study on the synthesis and properties of a promising nanostructure geometry, i.e. nanowires. HTC 116 colon cancer incubated with functionalised nanowires at 2 different concentrations (5 mg/ml and 10 mg/ml) retained a good cell viability. Cells incubated with 10mg/ml functionalised nanowires retained almost 90% cell survival after 16 hours (p < 0.05) whereas the cell survival fell by ≈30% (p < 0.05) for cells incubated with non-functionalised nanowires.