Sub-100 nm and ultra-thin hollow Gd2O3 nanospheres for effective magnetic resonance imaging T1 contrast agent

Gd2O3 nanomaterials with the highly exposed surface are proved to be effective magnetic resonance imaging (MRI) T 1 contrast agents. Most research efforts are focusing on ultra-small Gd2O3 nanoparticles, while sub-100 nm hollow Gd2O3 nanospheres with the ultra-thin shell are another strategy that can be more advantageous to prevent fast renal clearance and enhance cancer-targeted accumulation. Although there have been many reported methods for the synthesis of hollow nanospheres of various materials, the synthesis of Gd2O3 with an ultra-thin shell has not been achieved previously. In this article, we demonstrate a successful strategy for the synthesis of ultra-thin Gd(2)O(3)3 hollow nanospheres (HNS) with adjustable size and shell thickness through a SiO 2 nanoparticle templating method. The 30 nm Gd2O3 hollow nanospheres with a shell thickness of 2.9 nm showed high MRI T 1 relaxivity with an r 1 value of 3.77 mM -1 s -1 at 7 T. (C) 2021 Elsevier B.V. All rights reserved.