Orange-emissive carbon quantum dots for ligand-directed Golgi apparatus-targeting and in vivo imaging

The Golgi apparatus is one of the most important organelles in cells. Targeting and monitoring the morphology and structure of the Golgi apparatus are crucial and challenging. Aimed at the cysteine (Cys) receptor on the surface of the Golgi apparatus, ligand-directed carbon quantum dots (CQDs) were synthesized for Golgi apparatus-targeting imaging. In order to reduce the interference of tissue self-fluorescence and enhance the tissue penetration depth, orange-emissive levorotatory CQDs (L-CQDs) with Golgi apparatus-targeting ability were synthesized using the strategy of inheriting Cys residues and the inherent conjugated electronic structure of neutral red. They exhibit excitation-dependent, fluorescence stability, rich surface Cys residues, excellent biocompatibility, and low toxicity. As a Golgi apparatus-targeting agent, L-CQDs can quickly enter cells for Golgi apparatus-targeting imaging, and can also penetrate through biological tissue for imaging in vivo. The surface Cys residues of CQDs actively target the Cys receptors on the surface of the Golgi apparatus to achieve Golgi apparatus-targeting imaging.