Supramolecular Fluorescent Nanoparticles for Targeted Cancer Imaging

By a combination of excellent fluorescent performance with smart targeting capability for cancer-specific delivery, a promising class of calcein-based supramolecular fluorescent nanoparticles has been successfully prepared via a “bricks and mortar” strategy. Through tuning the molar ratio of adamantane-functionalized calcein (CA-AD)/β-cyclodextrin-grafted branched polyethylenimine (PEI-CD), the size of these fluorescent nanoparticles can be effectively controlled. Importantly, the β-cyclodextrin/adamantane (β-CD/AD = 1/1) host–guest interaction dramatically suppresses the π–π stacking and fluorescence self-quenching of calcein chromophores in water, leading to the formation of highly fluorescent nanoparticles. By introduction of the folate receptor, these fluorescent nanoparticles exhibit excellent cancer imaging efficiency.