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Large-scale synthesis of uniform and extremely small-sized iron oxide nanoparticles for high-resolution T1 magnetic resonance imaging contrast agents.
- Source :
-
Journal of the American Chemical Society [J Am Chem Soc] 2011 Aug 17; Vol. 133 (32), pp. 12624-31. Date of Electronic Publication: 2011 Jul 25. - Publication Year :
- 2011
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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 r(1) relaxivity of 4.78 mM(-1) s(-1) and low r(2)/r(1) ratio of 6.12, demonstrating that ESIONs can be efficient T(1) contrast agents. The high r(1) relaxivities of ESIONs can be attributed to the large number of surface Fe(3+) ions with 5 unpaired valence electrons. In the in vivo T(1)-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 T(1) MRI contrast agents in clinical settings.
- Subjects :
- Animals
Cell Line, Tumor
Contrast Media chemistry
Female
Ferric Compounds chemistry
Humans
Magnetic Resonance Angiography methods
Nanoparticles ultrastructure
Particle Size
Phosphines chemical synthesis
Phosphines chemistry
Polyethylene Glycols chemical synthesis
Polyethylene Glycols chemistry
Rats
Contrast Media chemical synthesis
Ferric Compounds chemical synthesis
Magnetic Resonance Imaging methods
Nanoparticles chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 1520-5126
- Volume :
- 133
- Issue :
- 32
- Database :
- MEDLINE
- Journal :
- Journal of the American Chemical Society
- Publication Type :
- Academic Journal
- Accession number :
- 21744804
- Full Text :
- https://doi.org/10.1021/ja203340u