Surface metal cation doping of maghemite nanoparticles: Modulation of MRI relaxivity features and chelator-free 68Garadiolabelling for dual MRI-PET imaging

Liron L. Israel, Farhad Karimi, Silvia Bianchessi, Eugenio Scanziani, Lorena Passoni, Michela Matteoli, Bengt Langström, Jean Paul Lellouche

Research output: Contribution to journalArticlepeer-review


Magnetically responsive maghemite (γ-Fe2O3) nanoparticles (NPs) are the subject of current interest due to their potential use as contrast agents for in vivo magnetic resonance imaging (MRI). In addition, PET (positron emission tomography) is another non-invasive molecular imaging modality based on nuclear medicine and short-lived positron radionuclides incorporated in various bioprobes. In previous work (Haviv et al 2010 J. Am. Chem. Soc. 132 12519-12521), Massart magnetite (Fe3O4) oxidation using ceric ammonium nitrate (CAN) was explored. The resulting hydrophilic maghemite (γ-Fe2O3) NPs formed a stable aqueous colloid/ferrofluid that disclosed a low level ofNP surface doping by Ce3/4+ atoms/cations. In this work, magnetically responsive gallium(III) or various other lanthanide(III) cation-doped maghemite NPs were prepared in different ways which influenced their r2∗ MRI relaxivities, which were usually strengthened vs those of known FDA approved ferrofluids. In addition, this resulting NPsurface chemistry enabled their direct labeling with PET-enabled 68Ga(III) cations (scheme 1) without using any attached chelating organic species/polymer, providing PETenabled radioactive magnetic NPs towards a novel dual PET/MRI imaging nanoscale agent.

Original languageEnglish
Article number095009
JournalMaterials Research Express
Issue number9
Publication statusPublished - Sep 1 2015


  • Ga-labelling of NPs
  • Chelator free labeling of NPs
  • Functional maghemite NPs
  • Metal cation doping process for NPsurface engineering
  • MRI/PET dual nanoparticulate imaging agents

ASJC Scopus subject areas

  • Biomaterials
  • Electronic, Optical and Magnetic Materials
  • Metals and Alloys
  • Polymers and Plastics
  • Surfaces, Coatings and Films

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