Large-Scale Synthesis of Uniform and Extremely Small-Sized Iron Oxide Nanoparticles for High-Resolution T1 Magnetic Resonance Imaging Contrast Agents
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- 11 July 2011
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 133 (32), 12624-12631
- https://doi.org/10.1021/ja203340u
Abstract
Uniform and extremely small-sized iron oxide nanoparticles (ESIONs) of < 4 nm were synthesized via the thermal decomposition of iron–oleate complex in the presence of oleyl alcohol. Oleyl alcohol lowered the reaction temperature by reducing iron–oleate complex, resulting in the production of small-sized nanoparticles. XRD pattern of 3 nm-sized nanoparticles revealed maghemite crystal structure. These nanoparticles exhibited very low magnetization derived from the spin-canting effect. The hydrophobic nanoparticles can be easily transformed to water-dispersible and biocompatible nanoparticles by capping with the poly(ethylene glycol)-derivatized phosphine oxide (PO-PEG) ligands. Toxic response was not observed with Fe concentration up to 100 μg/mL in MTT cell proliferation assay of POPEG-capped 3 nm-sized iron oxide nanoparticles. The 3 nm-sized nanoparticles exhibited a high r1 relaxivity of 4.78 mM–1 s–1 and low r2/r1 ratio of 6.12, demonstrating that ESIONs can be efficient T1 contrast agents. The high r1 relaxivities of ESIONs can be attributed to the large number of surface Fe3+ ions with 5 unpaired valence electrons. In the in vivo T1-weighted magnetic resonance imaging (MRI), ESIONs showed longer circulation time than the clinically used gadolinium complex-based contrast agent, enabling high-resolution imaging. High-resolution blood pool MR imaging using ESIONs enabled clear observation of various blood vessels with sizes down to 0.2 mm. These results demonstrate the potential of ESIONs as T1 MRI contrast agents in clinical settings.This publication has 88 references indexed in Scilit:
- Mesoporous Silica-Coated Hollow Manganese Oxide Nanoparticles as Positive T1 Contrast Agents for Labeling and MRI Tracking of Adipose-Derived Mesenchymal Stem CellsJournal of the American Chemical Society, 2011
- Magnetosome-like ferrimagnetic iron oxide nanocubes for highly sensitive MRI of single cells and transplanted pancreatic isletsProceedings of the National Academy of Sciences of the United States of America, 2011
- Surface Modification of Upconverting NaYF4 Nanoparticles with PEG−Phosphate Ligands for NIR (800 nm) Biolabeling within the Biological WindowLangmuir, 2009
- MR tracking of transplanted cells with “positive contrast” using manganese oxide nanoparticlesMagnetic Resonance in Medicine, 2008
- Chemical Design of Nanoparticle Probes for High‐Performance Magnetic Resonance ImagingAngewandte Chemie, 2008
- Self-Assembled Hybrid Nanoparticles for Cancer-Specific Multimodal ImagingJournal of the American Chemical Society, 2007
- Superparamagnetic Colloids: Controlled Synthesis and Niche ApplicationsAdvanced Materials, 2006
- One‐Nanometer‐Scale Size‐Controlled Synthesis of Monodisperse Magnetic Iron Oxide NanoparticlesAngewandte Chemie, 2005
- Magnetic relaxation switches capable of sensing molecular interactionsNature Biotechnology, 2002
- Theory of proton relaxation induced by superparamagnetic particlesThe Journal of Chemical Physics, 1999