title: Silica nanoparticles as substrates for chelator-free labeling of oxophilic radioisotopes.
abstract: Chelator-free nanoparticles for intrinsic radiolabeling are highly desirable for whole-body imaging and therapeutic applications. Several reports have successfully demonstrated the principle of intrinsic radiolabeling. However, the work done to date has suffered from much of the same specificity issues as conventional molecular chelators, insofar as there is no singular nanoparticle substrate that has proven effective in binding a wide library of radiosotopes. Here we present amorphous silica nanoparticles as general substrates for chelator-free radiolabeling and demonstrate their ability to bind six medically relevant isotopes of various oxidation states with high radiochemical yield. We provide strong evidence that the stability of the binding correlates with the hardness of the radioisotope, corroborating the proposed operating principle. Intrinsically labeled silica nanoparticles prepared by this approach demonstrate excellent in vivo stability and efficacy in lymph node imaging.
authors.affiliation: Department of Radiology, Memorial Sloan Kettering Cancer Center , New York, New York 10065, United States.
authors.forename: Travis M
authors.initials: TM
authors.lastname: Shaffer
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Wall
authors.forename: Stefan
authors.initials: S
authors.lastname: Harmsen
authors.forename: Valerie A
authors.initials: VA
authors.lastname: Longo
authors.forename: Charles Michael
authors.initials: CM
authors.lastname: Drain
authors.forename: Moritz F
authors.initials: MF
authors.lastname: Kircher
authors.forename: Jan
authors.initials: J
authors.lastname: Grimm
mesh_terms: D000818:Animals; D002614:Chelating Agents / Q000737:chemistry; D051379:Mice; D008819:Mice, Nude; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D064847:Multimodal Imaging; D053758:Nanoparticles / Q000737:chemistry*; D049268:Positron-Emission Tomography; D011868:Radioisotopes / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D014057:Tomography, X-Ray Computed
chemical_list: D002614:Chelating Agents; D011868:Radioisotopes; D012822:Silicon Dioxide
keywords: Intrinsic labeling; chelator-free; lymph node; nuclear imaging; radionuclide; silica nanoparticle