Facile Synthesis of Gadolinium Chelate-Conjugated Polymer Nanoparticles for Fluorescence/Magnetic Resonance Dual-Modal Imaging

Fluorescence (FL)/magnetic resonance (MR) dual-modal imaging nanoprobes are significant not only for cutting edge research in molecular imaging, but also for clinical diagnosis with high precision and accuracy. However, synthesis of FL/MR dual-modal imaging nanoprobes that simultaneously exhibit strong fluorescent brightness and high MR response, long-term colloidal stability with uniform sizes, good biocompatibility and a versatile surface functionality has proven challenging. In this study, the well-defined core–shell structured Gd3+ chelate-conjugated fluorescent polymer nanoparticles (Gd-FPNPs) that consist of rhodamine B (RB)-encapsulated poly(methyl methacrylate) (PMMA) cores and Gd3+ chelate-conjugated branched polyethylenimine (PEI) shells, are facilely synthesized via a one-step graft copolymerization of RB-encapsulated MMA from PEI-DTPA-Gd induced by tert-butyl hydroperoxide (TBHP) at 80 °C for 2 h. The mild synthesis route not only preserves the chemical environment for Gd3+ coordination, but a...