Gadolinium(III) Complexes with N-Alkyl-N-methylglucamine Surfactants Incorporated into Liposomes as Potential MRI Contrast Agents

Silva, Simone Rodrigues; Duarte, Érica Correia; Ramos, Guilherme Santos; Kock, Flávio Vinícius Crizóstomo; Andrade, Fabiana Diuk; Frézard, Frédéric; Colnago, Luiz Alberto; Demicheli, Cynthia

doi:10.1155/2015/942147

Cited by 10 publications

(2 citation statements)

References 37 publications

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“…Metal chelates can also be decorated onto the surface of liposome- or micelle-based NPs, and the resulting NPs afford r 1 as high as 134.8 mM -1 s -1 at 3.0 T due to prolonged rotational correlation times 84 - 86 . For instance, the Botta group developed a Gd(DOTA)-grafted lipid NP by modifying Gd(DOTA) with two carbon-chain anchors (i.e., GAC 12 ) and inserting them into the lipid bilayer ( Figure 3 A ) 87 .…”

Section: Nanoparticle or Macromolecule Contrast Agents With Enhanced mentioning

confidence: 99%

Surface impact on nanoparticle-based magnetic resonance imaging contrast agents

Zhang¹,

Liu²,

Chen³

et al. 2018

Theranostics

163

191

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Magnetic resonance imaging (MRI) is one of the most widely used diagnostic tools in the clinic. To improve imaging quality, MRI contrast agents, which can modulate local T1 and T2 relaxation times, are often injected prior to or during MRI scans. However, clinically used contrast agents, including Gd3+-based chelates and iron oxide nanoparticles (IONPs), afford mediocre contrast abilities. To address this issue, there has been extensive research on developing alternative MRI contrast agents with superior r1 and r2 relaxivities. These efforts are facilitated by the fast progress in nanotechnology, which allows for preparation of magnetic nanoparticles (NPs) with varied size, shape, crystallinity, and composition. Studies suggest that surface coatings can also largely affect T1 and T2 relaxations and can be tailored in favor of a high r1 or r2. However, the surface impact of NPs has been less emphasized. Herein, we review recent progress on developing NP-based T1 and T2 contrast agents, with a focus on the surface impact.

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Section: Nanoparticle or Macromolecule Contrast Agents With Enhanced mentioning

confidence: 99%

Surface impact on nanoparticle-based magnetic resonance imaging contrast agents

Zhang¹,

Liu²,

Chen³

et al. 2018

Theranostics

163

191

View full text Add to dashboard Cite

show abstract

“…It was demonstrated that the relaxivity of a dendrimer's Gd chelate is related to its mobility and that a high relaxivity rate is generally induced by a low mobility. High relaxivity can also be achieved by conjugation with macromolecules such as virus capsids [19, 20], nanoparticles [21], and liposomes [22, 23]. Manus et al prepared a Gd(III)-nanodiamond conjugate [Gd(III)-ND] with three Gd-chelate molecules.…”

Section: Introductionmentioning

confidence: 99%

Influence of Molecular Mobility on Contrast Efficiency of Branched Polyethylene Glycol Contrast Agent

Hsu

Mahara

Yamaoka

2018

Contrast Media & Molecular Imaging

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For a water-soluble polyethylene glycol (PEG) magnetic resonance imaging (MRI) contrast agent, it has been demonstrated that the contrast efficiency was increased with increased branched structure of the contrast agent. However, the cause of enhanced contrast efficiency by the branched structure has not been clarified. Hence, we investigate the cause of the contrast agent enhancement by changing the Gd introduction ratio of the eight-arm PEG from 1.97 to 4.07; furthermore, the terminal mobility of the contrast agents with different structures was evaluated using proton nuclear magnetic resonance (1H-NMR) spectroscopy. It was shown that the relaxivity and contrast luminance of the synthesized branched PEG-Gd contrast agents are larger than those of linear PEG-Gd and commercially available contrast agents. Additionally, the change in the Gd introduction ratio did not affect the contrast efficiency. The terminal mobility results measured by NMR show that the linewidth at half height became broader with an increased number of branches, implying that the mobility of branched PEG-Gd is slower than that of linear PEG-Gd. Interestingly, the linewidth at half height of different structures did not change in an organic solvent; this phenomenon appeared specifically in water. It is suggested that the stable branched structure enabled the improvement in the relaxivity and contrast luminance.

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Superfine Magnetic Resonance Imaging of the Cerebrovasculature Using Self‐Assembled Branched Polyethylene Glycol–Gd Contrast Agent

Mahara

Enmi

Hsu

et al. 2018

Macromolecular Bioscience

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Magnetic resonance angiography is an attractive method for the visualization of the cerebrovasculature, but small-sized vessels are hard to visualize with the current clinically approved agents. In this study, a polymeric contrast agent for the superfine imaging of the cerebrovasculature is presented. Eight-arm polyethylene glycol with a molecular weight of ≈17 000 Da conjugated with a Gd chelate and fluorescein (F-8-arm PEG-Gd) is used. The relaxivity rate is 9.3 × 10 m s , which is threefold higher than that of free Gd chelate. Light scattering analysis reveals that F-8-arm PEG-Gd is formed by self-assembly. When the F-8-arm PEG-Gd is intravenously injected, cerebrovasculature as small as 100 µm in diameter is clearly visualized. However, signals are not enhanced when Gd chelate and Gd chelate-conjugated 8-arm PEG are injected. Furthermore, small vasculature around infarct region in rat stroke model can be visualized. These results suggest that F-8-arm PEG-Gd enhances the MR imaging of cerebrovasculature.

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Gadolinium(III) Complexes with N-Alkyl-N-methylglucamine Surfactants Incorporated into Liposomes as Potential MRI Contrast Agents

Cited by 10 publications

References 37 publications

Surface impact on nanoparticle-based magnetic resonance imaging contrast agents

Surface impact on nanoparticle-based magnetic resonance imaging contrast agents

Influence of Molecular Mobility on Contrast Efficiency of Branched Polyethylene Glycol Contrast Agent

Superfine Magnetic Resonance Imaging of the Cerebrovasculature Using Self‐Assembled Branched Polyethylene Glycol–Gd Contrast Agent

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