One-pot preparation of biocompatible folate-functionalized graphitic carbon nitride quantum dots for targeted bioimaging

Graphitic carbon nitride quantum dots (CNQDs) have been widely used in bioimaging due to the unique structure and optical properties, but only a few works demonstrate targeted imaging. Herein, we report a universal one-pot strategy for preparation of targeting agent functionalized CNQDs by taking folate (FA) as an example through hot-fluid annealing of triazine tectons and derived FA. The FA-CNQDs with size of 3 ∼ 8 nm exhibit bright fluorescence, favorable colloidal stability, and well cytocompatibility and in vivo biocompatibility. The remarkable performance of FA-CNQDs in targeted imaging is demonstrated by incubation study with folate receptor overexpressed cancer cells and the cell derived multicellular spheroids. This convenient strategy would open a new avenue for synthesis of various functionalized CNQDs.