Bright NIR-II Fluorescent Small-Molecule Nanoparticles with Reduced Intermolecular Interaction for Targeted in Vivo Inflammation Imaging

Though biocompatible small-molecule-based NIR-II fluorescent nanoparticles (NPs) are highly desirable in fluorescence imaging (FI), the fluorescence quantum yield is relatively poor due to the significant aggregation-caused quenching and the heavy intermolecular interactions. Herein, we conveniently obtained bright NIR-II fluorescent small-molecule NPs (TQFPNs) fabricated from a polystyrene (PS)-modified fluorophore (TQF-PS). Our prepared PS-modified NPs displayed 3.2-fold higher emission intensity than that of non-PS polymer chain NPs (TQF@NPs) in vitro. Finally, bright and high-resolution NIR-II FI of a rheumatoid arthritis mouse model and a pneumonia mouse model using TQFPNs demonstrated its successful application for targeted in vivo inflammation imaging.