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Characterization of a Manganese‐Containing Nanoparticle as an MRI Contrast Agent
Author(s) -
Gianolio Eliana,
Bäckström Sania,
Petoral Rodrigo M.,
Olsson Anders,
Aime Silvio,
Axelsson Oskar
Publication year - 2019
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201801472
Subject(s) - chemistry , nanoparticle , manganese , gadolinium , mri contrast agent , molecule , chelation , nuclear magnetic resonance , paramagnetism , analytical chemistry (journal) , nuclear chemistry , inorganic chemistry , nanotechnology , chromatography , organic chemistry , materials science , physics , quantum mechanics
We present relaxivity and physicochemical data for a high relaxivity, manganese‐containing, nanoparticle‐based, and tumor selective MRI contrast agent, SN132D. The nanoparticles have a diameter of 5–6 nm, selected to give a compromise between renal excretion and tumor contrast, based on the Enhanced Permeability and Retention effect. The per manganese relaxivity (r 1 ) is 24.8 ± 0.2 m m –1 Mn s –1 at 1.5 T and 37 °C in water, corresponding to per nanoparticle relaxivity of 347 ± 3 m m –1 s –1 . The NMRD profiles in both water and serum showed a peak in r 1 in the frequency range 20–40 MHz, which is characteristic of slowly moving paramagnetic systems. The r 1 decreases when the temperature is increased from 25 °C to 37 °C, indicating fast exchange dynamics of the coordinated water molecules. The exchange time constant of the whole water molecule, τ M O , was 6 ns. The r 1 in serum is significantly higher than in water, due to an increase in medium viscosity and chelation of 18.9 ± 2.0 % of Mn II ions to human serum components, most likely human serum albumin. The r 1 is stable in the pH range 3–10. The per Mn relaxivity is among the highest reported for Mn‐containing systems and far higher than those of the clinically used gadolinium‐based contrast agents.