Manganese-grafted detonation nanodiamond, a novel potential MRI contrast agent

Aiming to develop versatile MRI contrast agents, we report on preparation and magnetic resonance study of a novel nanomaterial - detonation nanodiamond (DND) with manganese ions directly grafted to its surface. The sample was prepared by reacting an aqueous nanodiamond suspension with an aqueous solution of manganese sulfate. We present clear evidence on chemical binding of Mn2+ ions to nanodiamond surface; ions interact with electron and nuclear spins of a diamond nanoparticle, thus accelerating spin-lattice relaxation. The distance between Mn2+ ion and diamond surface was estimated from the 13C NMR relaxation data. Comparison of the interaction of Mn ions with DND to that in the recently studied Gd-grafted DND suggests that Mn-DND will be a potential material as an MRI contrast agent.