Dextran‐Coated Ultrasmall Gd₂O₃ Nanoparticles as Potential T₁ MRI Contrast Agent

Abstract

Ultrasmall gadolinium oxide (Gd2O3) nanoparticles coated with dextran (trueM‾ r=1500 amu) were prepared through one‐pot synthesis and their potential to act as a T1 MRI contrast agent was investigated. The dextran‐coated ultrasmall Gd2O3 nanoparticles were highly water‐dispersible, with an average particle diameter of 1.5 nm and an average hydrodynamic diameter of 12.4 nm, and non‐toxic, as determined in a cellular cytotoxicity test. The longitudinal (r1) and transverse (r2) water proton relaxivities were estimated to be 12.2 and 29.3 s−1mM−1 (r2/r1=2.4), respectively, larger than those of commercial Gd‐chelates. This r1 value is also greater than those for previously reported dextran‐coated large Gd2O3 nanoparticles with particle diameter bigger than 20 nm. Positive contrast magnetic resonance (MR) images were obtained after intravenous injection of a sample solution into a mouse tail, demonstrating the potential of dextran‐coated ultrasmall Gd2O3 nanoparticles as a T1 MRI contrast agent.

Recent Advances in Gadolinium Based Contrast Agents for Bioimaging Applications

“…Dextran coated Gd-NPs synthesized through a one-pot synthesis approach were found to be highly water-dispersible and non-toxic as determined in a cellular cytotoxicity test. relaxivities r 1 = 12.2 and r 2 = 29.3 s −1 ·mM −1 with r 2 /r 1 = 2.4 were observed [ 122 ]. In another study, dextran-coated Gd-phosphate NPs was employed both as tumor-targeted MRI CAs and as a vehicle for drug delivery to tumors [ 123 ].…”

Understanding Nanoparticle Toxicity to Direct a Safe-by-Design Approach in Cancer Nanomedicine

“…Engineering the surface of the nanoparticles with large numbers of paramagnetic centers can yield superior T1 contrast agents in comparison to clinical Gd-chelates. Nanoparticle T1 contrast agents can have higher T1 relaxivity [29][30][31][32][33][34][35][36] and longer blood circulation time [29,34,35,37]. In addition, the Gd 3+ ions are embedded in the crystal matrix of the nanoparticle; hence, significant leaching of Gd 3+ can be prevented, minimizing the risk of toxicity [29,35,36].…”

Asymmetric attachment and functionalization of plasmonic nanoparticles on ceramic interfaces

“…While optical methods are range limited by light absorption of the examined body, and still, in need of invasive techniques, magnetic resonance imaging (MRI) is suitable for non-invasive imaging of malignant tissues. Being well-established as a strong T 1 contrast agent [6,7], Gd 2 O 3 NPs bare a large magnetic moment of 7.94 μB per Gd 3+ ion, leading to a high longitudinal relaxivity of nearby water protons.…”