Chelator free gallium-68 radiolabelling of silica coated iron oxide nanorods via surface interactionsElectronic supplementary information (ESI) available. See DOI: 10.1039/c5nr02753e

• Main Authors: Burke, Benjamin P, Baghdadi, Neazar, Kownacka, Alicja E, Nigam, Shubhanchi, Clemente, Gonçalo S, Al-Yassiry, Mustafa M, Domarkas, Juozas, Lorch, Mark, Pickles, Martin, Gibbs, Peter, Tripier, Raphaël, Cawthorne, Christopher, Archibald, Stephen J
• Format: Article
• Language: English
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c5nr02753e

The commercial availability of combined magnetic resonance imaging (MRI)/positron emission tomography (PET) scanners for clinical use has increased demand for easily prepared agents which offer signal or contrast in both modalities. Herein we describe a new class of silica coated iron-oxide nanorods (NRs) coated with polyethylene glycol (PEG) and/or a tetraazamacrocyclic chelator (DO3A). Studies of the coated NRs validate their composition and confirm their properties as in vivo T 2 MRI contrast agents. Radiolabelling studies with the positron emitting radioisotope gallium-68 ( t 1/2 = 68 min) demonstrate that, in the presence of the silica coating, the macrocyclic chelator was not required for preparation of highly stable radiometal-NR constructs. In vivo PET-CT and MR imaging studies show the expected high liver uptake of gallium-68 radiolabelled nanorods with no significant release of gallium-68 metal ions, validating our innovation to provide a novel simple method for labelling of iron oxide NRs with a radiometal in the absence of a chelating unit that can be used for high sensitivity liver imaging. Silica coated iron oxide nanorods can be radiolabelled with gallium-68 without the need for a chelator to give in vivo stable multimodal PET/MR imaging agents.