Cobalt nanoparticles as a novel magnetic resonance contrast agent—relaxivities at 1.5 and 3 Tesla

Abstract

Two samples of polymer-coated cobalt nanoparticles were synthesized and dispersed in agarose gel and water. The relaxivities r1 and r2 of the two samples were obtained at different temperatures (25, 37 and 40 degrees C) and magnetic field strengths (1.5 and 3 T). The average cobalt core diameters of the two samples were 3.3 and 3.9 nm (measured by transmission electron microscopy); the corresponding average total diameters (cobalt core + polymer coating) were 13 and 28 nm (measured by dynamic light scattering). The larger particles had the higher r1 relaxivity, whilst r2 was similar for the two samples. There was no significant change in r1 or r2 relaxivities with temperature but r1 at 1.5 T was approximately double the value at 3 T. The highest relaxivities were obtained at 1.5 T with values for r1 and r2 of 7.4 and 88 mM(-1) s(-1), respectively. These values are similar to those reported for iron oxide with larger core size, suggesting the potential of the cobalt nanoparticles for development and future use as a negative contrast agent.

Iron Oxide-Based Nanostructures for MRI and Magnetic Hyperthermia

“…This includes the design of nanoparticles by modification of shape, such as polyhedral [88], nanocubes [89], superparamagnetic colloidal nanocrystals [90] and multiple magnetite nanocrystals [41]; and the use of manganese nanoparticles [91], cobalt nanoparticles [92] and quantum dot-capped magnetite nanorings [93], among others.…”

Toxicity of cobalt oxide nanoparticles to normal cells; an in vitro and in vivo study

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Co9Se8 Nanoplates as a New Theranostic Platform for Photoacoustic/Magnetic Resonance Dual‐Modal‐Imaging‐Guided Chemo‐Photothermal Combination Therapy

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