Synthesis of core / shell nanoparticles for dual contrast MRI

This master's thesis was performed at Genovis AB, Sweden, and with the purpose to synthesize a new contrast agent for MRI. MRI is a modern noninvasive tool for imaging biological tissue. To enhance the image quality two different contrast enhancing agents are used, in two different imaging modes, one is called T1 and gives a positive enhancing of the MRI signal and the other is called T2 and increases contrast by reducing signal strength. Commercial contrast agents is optimized for only one mode and both modes have drawbacks reducing image quality. This work details the synthesis of a dual core/shell contrast for imaging in both modes. A particle created by using a core of iron oxide and a outer shell of gadolinium and capable of achieving simultaneous T1 and T2 contrast. This was verified by in vitro MRI and the structure by TEM studies. The toxicity of the particles were evaluated by the use of cellcultures. The dual mode nanoparticles can by switching mode give complementary information that cannot be obtained by the use of only one type of contrast agent. This leads not only to more accurate and diagnostic useful images but also gives the particles a self-confirmation ability, allowing the MRI operator to easily identify the agent by shifting mode and making the interpretation of the image easier and faster.