Synthesis and Characterization of Ultrasmall Gadolinium Oxide Nanoparticles for Advance T1 MRIcontrast Agent

Woo Choul Heo¹, Ja Young Park¹, Kattel Krishna¹, Wenlolg Xu¹, Tirusew Tegafaw Mengesha¹, Badrul Alam Bony¹, Gang Ho Lee¹

We reported the synthesis and characterization of ultrasmall gadolinium oxide nanoparticles. In this work, the ultrasmall gadolinium oxide nanoparticles with an average d of 1 nm having r1 of 9.9 s-1 mM-1, which is much larger than those of Gd(III)-chelates. It seems that surface Gd(III) ions in gadolinium oxide nanoparticles cooperatively induce the longitudinal relaxation of the water proton. As a result, this cooperative induction effect accelerates the longitudinal relaxation of the water proton, providing a larger r1 than Gd(III)-chelates. We address this by carefully examining the d dependence of r1. We finally took in vivo T1 MR images of a rat with a brain tumor by using D-glucuronic acid coated ultrasmall gadolinium oxide nanoparticles and observed a clear contrast enhancement in T1 MR images of the tumor after injection.