Chelating moieties can be incorporated in micelles or attached to the surface of metal nanoparticles through sulfur linkages via physi- and chemisorption. Methods are well developed for producing nanoparticles that are highly monodisperse, which is important to ensure a uniform response when the agent is administered to an organism. The resulting constructs consisting of derivatized micelles and metal particles have been characterized by solution NMR and show great potential as imaging agents for magnetic resonance imaging (MRI).