Novel Nanoparticle Contrast Agents for Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) is an important diagnostic tool in both clinical and research environments. In order to improve sensitivity, contrast agents (CAs) are often administered prior to or during imaging sessions. We have developed a number of novel nanoparticle CAs consisting of metal-oxo clusters with high spins (molecular magnets) encapsulated in polymer nanocarriers. The pure clusters show good relaxivities, which can be further enhanced by encapsulation in the polymers. In some cases, values of the relaxivity comparable to or larger than those of commercially available CAs can be achieved. We will report on the contrast enhancement from several of these nanoparticles in both phantom and in vivo images.