Ligand-free gadolinium oxide for in vivo T1-weighted magnetic resonance imaging

Abstract

Gadolinium oxide (Gd2O3), which can be used as a T1-weighted magnetic resonance imaging (MRI) contrast agent, has attracted intense attention in recent years. In this paper, ligand-free monoclinic Gd2O3 nanocrystals of 7.1 nm in diameter are synthesized by a simple and green approach, namely microsecond laser ablation of a gadolinium (Gd) target in deionized water. These nanocrystals obtain high r1 relaxivity of 5.53 s(-1) mM(-1), and their low toxicity was demonstrated by the cell viability of S18 cells and apoptosis in RAW264.7 cells. In vitro and in vivo MR images show these particles to be good T1-weighted MRI contrast agents. Base on the experimental results and theoretical analysis, we suggest that the purity of the Gd2O3 contributes to its high r1 relaxivity value, while the low toxicity is due to its good crystallinity. These findings show that laser ablation in liquid (LAL) is a promising strategy to synthesize ligand-free monoclinic Gd2O3 nanocrystals for use as high efficient T1-weighted MRI contrast agents.

Synthesis and Characterization of Rare‐Earth Orthoferrite LnFeO3 Nanoparticles for Bioimaging

“…For the same Ln, r 2 was found to increase with the magnetic field B 0 or with B 0 2 , , , . The dependence of r 2 on the particle size is more complex, as found experimentally, , and predicted by the OS theory , . For small particles, the Motional Averaging Regime (MAR) operates, and r 2 is proportional to ( µ eff ) 2 B 0 2 and inversely proportional to the radius of the NP.…”

“…It is well‐known that the r 1 values for NPs increase as their size decreases, as the number of paramagnetic metal ions at the surface increases with their ( S/V ) ratio. Depending on the magnetic field, the r 1 values of Gd 2 O 3 NPs can go up to 12 (1.5 T) or 10 s –1 m m –1 (3 T) with optimal particle sizes of 1.6 and 3.8 nm, respectively , , , …”

PAMAM dendrimer based targeted nano-carrier for bio-imaging and therapeutic agents

“…124 Dendrimers can be used to either encapsulate or directly conjugate paramagnetic materials. [128][129][130][131][132][133] According to Ahmad et al,134 gadolinium oxide nanoparticles with dual imaging capacity can be used for MRI and CT. 126 In a recent communication, gadolinium (Gd) labeled nanoclusters functionalized with folic acid ligands was reported as a tumor-targeted T1 MRI contrast agent in vivo.…”

Molecular architecture control in synthesis of spherical Ln-containing nanoparticles

“…21 We have previously reported that Ln carbonate NPs (turning into oxides upon calcination) can be readily prepared via controlled microwave-assisted seed growth. 23 Alternatively, a laser ablation method performed by focusing the laser beam onto a Gd target has been described, 24 resulting in spherical Gd 2 O 3 particles with an average diameter of 7 nm. Finally, the solvothermal method is dominating in the synthesis of upconversion NPs with highly controlled size and morphological uniformity.…”