Gadolinium-loaded nanoparticles: New contrast agents for magnetic resonance imaging

We have developed a new class of metal-loaded nanoparticles that have poten tial as contrast agents for medical imaging. These polymeric materials have a core-shell morphology where the interior is a functionalized polymer, th at provides high affinity for a specific metal, and the shell consists of a porous hydrophobic polymer that modulates access to the core. In the prese nt case, the nanoparticles an loaded with Gd3+ to provide contrast in magne tic resonance (MR) imaging. The Gd3+-loaded nanoparticles described in this paper have a diameter of 120 nm and are, therefore, small enough to pass e asily through the vasculature. These particles have been shown to reduce re laxation times in vitro, and provide excellent contrast when used to image the heart and gastrointestinal tract in a rat animal model.