Core/shell Fe3O4/Gd2O3 nanocubes as T1–T2 dual modal MRI contrast agents

Abstract

T ₁–T₂ dual modal magnetic resonance imaging (MRI) has attracted considerable interest because it offers complementary diagnostic information, leading to more precise diagnosis. To date, a number of nanostructures have been reported as T₁–T₂ dual modal MR contrast agents (CAs). However, hybrids of nanocubes with both iron and gadolinium (Gd) elements as T₁–T₂ dual modal CAs have not been reported. Herein, we report the synthesis of novel core/shell Fe₃O₄/Gd₂O₃ nanocubes as T₁–T₂ dual-modal CAs and their application for enhanced T₁–T₂ MR imaging of rat livers. A relaxivity study at 1.5 T indicated that our Fe₃O₄/Gd₂O₃ nanocubes have an r₁ value of 45.24 mM⁻¹ s⁻¹ and an r₂ value of 186.51 mM⁻¹ s⁻¹, which were about two folds of those of Gd₂O₃ nanoparticles and Fe₃O₄ nanocubes, respectively. In vivo MR imaging of rats showed both T₁-positive and T₂-negative contrast enhancements in the livers. We envision that our Fe₃O₄/Gd₂O₃ nanocubes could be applied as T₁–T₂ dual modal MR CAs for a wide range of theranostic applications in the near future.