Tailored Nanoscale Contrast Agents for Magnetic Resonance Imaging

Published

December 30, 2005

Author(s)

Alexander J. Barker, Brant Cage, Stephen E. Russek, Ruchira Garg, R Shandas, Conrad Stoldt

Abstract

Two potential molecular imaging vectors are investigated for material properties and magnetic resonance imaging (MRI) contrast improvement. Monodisperse magnetite (Fe₃O₄) nanocrystals ranging in size from 7 to 22 nm are solvothermally synthesized by thermolysis of Fe(III) acetylacetonate (Fe(AcAc)₃), both with and without the use of heptanoic acid (HA) as a capping ligand. For the resulting Fe₃O₄ nanocrystals, X-Ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and superconducting quantum interference device magnetometry (SQUID) is used to identify the average particle size, monodispersity, crystal symmetry, and magnetic properties of the ensembles as a function of time. The characterization study indicates that the HA synthesis route at 3 hours produced nanoparticles with the greatest magnetic anisotropy (15.8 x 10⁴ J/m³). The feasibility of Fe₈ single molecule magnets (SMMs) as a potential MRI contrast agent is also examined. SQUID magnetization measurements are used to determine anisotropy and saturation of the potential agents. The effectiveness of the Fe₃O₄ nanocrystals and Fe₈ as potential MRI molecular probes is evaluated by MRI contrast improvement using 1.5 mL phantoms dispersed in de-ionized water. Results indicate that the magnetically optimized Fe₃O₄ nanocrystals and Fe₈ SMMs hold promise for use as contrast agents based on the reported MRI images and solution phase T₁/T₂ shortening.

Proceedings Title

Proceedings of IMECE2005, 2005 ASME International Mechanical Engineering Congress and Exposition

Conference Dates

November 5-11, 2005

Conference Location

Orlando, FL, USA

Conference Title

ASME International Mechanical Engineering Congress and Exposition

Pub Type

Conferences

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Keywords

contrast agent, Fe₃O₄, Fe₈, MRI

Citation

Barker, A. , Cage, B. , Russek, S. , Garg, R. , Shandas, R. and Stoldt, C. (2005), Tailored Nanoscale Contrast Agents for Magnetic Resonance Imaging, Proceedings of IMECE2005, 2005 ASME International Mechanical Engineering Congress and Exposition, Orlando, FL, USA, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=32015 (Accessed April 18, 2024)