88.
The facile hydrothermal synthesis of polyethyleneimine (PEI)‐coated iron oxide (Fe
3O
4) nanoparticles (NPs) doped with Gd(OH)
3 (Fe
3O
4‐Gd(OH)
3‐PEI NPs) for dual mode T
1‐ and T
2‐weighted magnetic resonance (MR) imaging applications is reported. In this approach, Fe
3O
4‐Gd(OH)
3‐PEI NPs are synthesized via a hydrothermal method in the presence of branched PEI and Gd(III) ions. The PEI coating onto the particle surfaces enables further modification of poly(ethylene glycol) (PEG) in order to render the particles with good water dispersibility and improved biocompatibility. The formed Fe
3O
4‐Gd(OH)
3‐PEI‐PEG NPs have a Gd/Fe molar ratio of 0.25:1 and a mean particle size of 14.4 nm and display a relatively high
r2 (151.37 × 10
?3m
?1 s
?1) and
r1 (5.63 × 10
?3m
?1 s
?1) relaxivity, affording their uses as a unique contrast agent for T
1‐ and T
2‐weighted MR imaging of rat livers after mesenteric vein injection of the particles and the mouse liver after intravenous injection of the particles, respectively. The developed Fe
3O
4‐Gd(OH)
3‐PEI‐PEG NPs may hold great promise to be used as a contrast agent for dual mode T
1‐ and T
2‐weighted self‐confirmation MR imaging of different biological systems.
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