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Updated: May 18, 2026
Cell Labeling and Targeting with Superparamagnetic Iron Oxide Nanoparticles
Published on: October 19, 2015
Negatively charged superparamagnetic iron oxide nanoparticles: a new blood-pooling magnetic resonance contrast agent
Norihisa Nitta1, Keiko Tsuchiya, Akinaga Sonoda
1Department of Radiology, Shiga University of Medical Science, Tsukinowaco, Seta, Otsu, Shiga 520-2192, Japan. r34nitta@belle.shiga-med.ac.jp
Purpose:
Our purpose was to investigate the utility of superparamagnetic iron-oxide nanoparticles (SPIO) as a blood-pooling contrast agent at magnetic resonance imaging (MRI).
Materials And Methods:
We studied four contrast agents: carboxymethyl-diethylaminoethyl dextran magnetite SPIO (CMEADM-S, diameter 54 nm), negatively charged CMEADM ultrasmall SPIO (CMEADM-U, 32 nm), alkali-treated dextran magnetite SPIO (ATDM-S, 55 nm), and ATDM ultrasmall SPIO (ATDM-U, 28 nm) carrying a neutral charge. Each contrast agent (80 μmol/kg) was injected intraperitoneally into apolipoprotein E (apoE) mice and the tissue iron concentration was measured 30-, 60-, 180-, and 300-min later by nuclear MR. For MR angiographic (MRA) evaluation, we injected the agents into the auricular vein of four groups of 15 rabbits. Immediately and 30-, 60-, 180-, and 300-min later, three rabbits from each group were subjected to MRI. The organ/background signal ratio (SR) was calculated. Statistical analyses were performed with Tukey's honestly significant difference (HSD) test.
Results:
At 60 and 180 min, blood-iron concentration of CMEADM-U was significantly different from other contrast agents. In the abdominal aorta and inferior vena cava, SR of CMEADM-U was higher at 180 and 300 min than of the other contrast agents. In the thoracic aorta, there was no difference in SR at 300 min between CMEADM-U and CMEADM-S.
Conclusion:
Negatively charged SPIO nanoparticles may be useful as a blood-pooling contrast agent.
