Encapsulating (111)In in nanocontainers for scintigraphic imaging: synthesis, characterization, and in vivo biodistribution.

A new strategy for the radiolabeling of porous nanocontainers has been developed, and the first experiments in vivo are reported. Our approach consists of the use of nanometer-sized zeolites whose channels have been filled with the positively charged gamma-emitter (111)In(3+) via simple ion exchange. To avoid leaching of the isotope under physiological conditions, the entrances of the channels have been closed using a specifically designed molecular stopcock.