Chelate-free metal ion binding and heat-induced radiolabeling of iron oxide nanoparticles† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c4sc02778g Click here for additional data file.

1 The Athinoula A. Martinos Center for Biomedical Imaging, 149 13th Street, Suite 2301, Charlestown, Massachusetts, United States of America, 02129 2 Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, Massachusetts, United States of America, 02114 3 Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-LaueStr. 7, Building N140/Ground Floor, 60438 Frankfurt am Main, Germany 4 Center for Advanced Molecular Imaging Sciences, Massachusetts General Hospital, Harvard Medical School, 149 13th Street, Charlestown, Massachusetts, United States of America, 02129 5 Division of Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, 55 Fruit Street, White 427, Boston, Massachusetts, United States of America, 02114