Organic Nanoprobes for Fluorescence and 19F Magnetic Resonance Dual-Modality Imaging

Multimodal imaging techniques have been demonstrated to be greatly advantageous in achieving accurate diagnosis and gained increasing attention in recent decades. Herein, we present a new strategy to integrate the complementary modalities of F-19 magnetic resonance imaging (F-19 MRI) and fluorescence imaging (FI) into a polymer nanoprobe composed of hydrophobic fluorescent organic core and hydrophilic fluorinated polymer shell. The alkyne-terminated fluorinated copolymer (Pn) of 2,2,2-trifluoroethyl acrylate (TFEA) and poly(ethylene glycol) methyl ether acrylate (PEGA) was first prepared via atom transfer radical polymerization (ATRP). The PEGA plays an important role in both improving F-19 signal and modulating the hydrophilicity of Pn. The alkynyl tail in Pn is readily conjugated with azide modified tetra-phenylethylene (TPE) through click chemistry to form azo polymer (TPE-azo-Pn). The core-shell nanoprobes (TPE-P3N) with an average particle size of 57.2 +/- 8.8 nm are obtained via self-assembly with ultrasonication in aqueous solution. These nanoprobes demonstrate high water stability, good biocompatibility, strong fluorescence and good F-19 MRI performance, which present great potentials for simultaneous fluorescence imaging and F-19-MR imaging.