(A). Structural representation of the trimetallic nitride template metallofullerene–based heranostic agent Gd3N@C80. Therapeutic, covalent linkage, and diagnostic regions are denoted by pink, purple, and blue, respectively. (B). Dynamic equilibrium of aqueous clustering properties of Gd3N@C80, which shifts to larger clusters with decreasing pH. (Reproduced with permission from Ref (43). Copyright 2011 Radiological Society of North America).