Rapid microwave-assisted synthesis of PVP-coated ultrasmall gadolinium oxide nanoparticles for magnetic resonance imaging

Abstract Synthesis of polyvinyl pyrrolidone (PVP) coated ultrasmall Gd 2 O 3 nanoparticles (NPs) with enhanced T 1 -weighted signal intensity and r 2 / r 1 ratio close to unity is performed by a microwave-assisted polyol process. PVP coated Gd 2 O 3 NPs with spherical shape and uniform size of 2.5 ± 0.5 nm have been synthesized below 5 min and structure and morphology confirmed by HRTEM, XRD and FTIR. The longitudinal ( r 1 ) and transversal relaxation ( r 2 ) of Gd 2 O 3 NPs is measured by a 3 T MRI scanner. The results showed considerable increasing of relaxivity for Gd 2 O 3 NPs in comparison to gadolinium chelates which are commonly used for clinical magnetic resonance imaging. In addition, a mechanism for Gd 2 O 3 NPs formation and in situ surface modification of PVP-grafted Gd 2 O 3 NPs is proposed.