Gadolinium-Labeled Nanoparticles for Magnetic Resonance ImagingPublic Deposited
Magnetic resonance imaging (MRI) is a powerful technique used in clinical medicine and biomedical research to conduct noninvasive imaging of tissues and organisms. Chelated gadolinium is often used as an MRI contrast agent to improve the spatial resolution of these images. Recently developed “smart” MRI contrast agents respond to specific biological triggers by controlling inner-sphere water access to a chelated gadolinium(III) ion. However, a stronger signal is required for many imaging applications. Nanoparticles grafted with DOTA-chelated Gd(III) were synthesized to achieve this signal amplification. They exhibit a threefold increase in T1 relaxivity per gadolinium ion because the tumbling rate of the Gd(III) complexes is reduced. Control studies indicate, however, that Gd(III) may bind nonspecifically to silica nanoparticles during synthesis. This research applies a better approach, where gadolinium is chelated before being added to the nanoparticles. The results demonstrate the potential of this grafting technique to improve the sensitivity of DOTA-derived bioactivateable contrast agents.