Ultrasmall Water‐Soluble and Biocompatible Magnetic Iron Oxide Nanoparticles as Positive and Negative Dual Contrast Agents |
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| Authors: | Zhen Li Pei Wei Yi Qiao Sun Hao Lei Hong Li Zhao Zhong Hua Zhu Sean C Smith Min Bo Lan Gao Qing Lu |
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| Affiliation: | 1. ARC Centre of Excellence for Functional Nanomaterials, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, QLD 4072, Australia;2. State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, WuHan Institute of Physics & Mathematics, Chinese Academy of Sciences, WuHan 430071, P. R. China;3. Centre for Computational Molecular Science, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, QLD 4072, Australia;4. Shanghai Key Laboratory of Functional Materials Chemistry, East China University of Science and Technology, Shanghai 200237, P. R. China;5. School of Chemical Engineering, The University of Queensland, QLD 4072, Australia |
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| Abstract: | Monodispersed water‐soluble and biocompatible ultrasmall magnetic iron oxide nanoparticles (UMIONs, D = 3.3 ± 0.5 nm) generated from a high‐temperature coprecipitation route are successfully used as efficient positive and negative dual contrast agents of magnetic resonance imaging (MRI). Their longitudinal relaxivity at 4.7 T (r1 = 8.3 mM?1 s?1) is larger than that of clinically used T1‐positive agent Gd‐DTPA (r1 = 4.8 mM?1 s?1), and three times that of commercial contrast agent SHU‐555C (r1 = 2.9 mM?1 s?1). The transversal relaxivity (r2 = 35.1 mM?1 s?1) is six times that of Gd‐DTPA (r2 = 5.3 mM?1 s?1), half of SHU‐555C (r2 = 69 mM?1 s?1). The in vivo results show that the liver signal from T1‐weighted MRI is positively enhanced 26%, and then negatively decreased 20% after injection of the iron oxide nanoparticles, which is stronger than those obtained from Gd‐DTPA (<10%) using the same dosage. The kidney signal is positively enhanced up to 35%, similar to that obtained from Gd‐DTPA. Under T2‐weighted conditions, the liver signal is negatively enhanced ?70%, which is significantly higher than that from Gd‐DTPA (?6%). These results demonstrate the great potential of the UMIONs in dual contrast agents, especially as an alternative to Gd‐based positive contrast agents, which have risks of inducing side effects in patients. |
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| Keywords: | dual contrast agents iron oxide magnetic resonance imaging magnetic nanoparticles coprecipitation |
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