One-Step Loading of Gold and Gd 2 O 3 Nanoparticles within PEGylated Polyethylenimine for Dual Mode Computed Tomography/Magnetic Resonance Imaging of Tumors.

We report here a facile method for one-step loading of gold (Au) and gadolinium oxide (Gd 2 O 3 ) nanoparticles (NPs) within polyethylenimine (PEI) premodified with polyethtylene glycol (PEG) for dual mode computed tomography (CT) and magnetic resonance (MR) imaging of tumors. PEGylated PEI was used as a template to complex Au(III) and Gd(III) salts, followed by sodium borohydride reduction and acetylation of remaining PEI surface amines to generate the hybrid PEI@Au/Gd 2 O 3 NPs. The hybrid NPs exhibit a remarkable colloidal stability and cytocompatibility and possess a high X-ray attenuation efficacy and r 1 relaxivity, enabling their uses for dual mode CT/MR imaging of tumors.