Biofunctionalised nanoparticles – new MRI contrast agents
Master thesis in Medical Biology by Anna Klasson
Gadolinium oxide particles, Gd2O3, have in this work been studied as a potentially new and improved contrast agent for Magnetic Resonance Imaging (MRI).
Magnetic resonance is a phenomenon that was discovered in the 1920s and it is based on the magnetic properties of hydrogen nuclei. Hydrogen protons possess certain spin that gives them suitable magnetic properties and make them interact with external magnetic fields. This is the basis of MRI techniques.
Molecules located near the hydrogen nuclei can alter the magnetic properties of the hydrogen. This is used when supplying a contrast agent before MR scanning to improve the contrast in images. In this study the relaxation properties of Gd2O3 particles in water, cell culture medium and cells have been measured and evaluated. This has been compared to already existing contrast agent Magnevist®, which is a gadolinium ion complex.
Results show that Gd2O3 particles capped with diethyleneglycol (DEG) give very high relaxivity to water protons and would thus be a suitable contrast agent. The relaxivity of these particles were twice as high as for Magnevist®.
Relaxation time measurements of monocytes incubated with the particles show that the cells do uptake or bind Gd2O3-DEG. This indicates that the particles keep their excellent relaxation properties also in biological environments.
Gd2O3 particles need to be further investigated as a potential contrast agent and these results also suggest that the particles might be useful in other areas, such as labelling cells or to study biological or chemical reactions.