Preparation of One-Emission Nitrogen-Fluorine-Doped Carbon Quantum Dots and Their Applications in Environmental Water Samples and Living Cells for ClO- Detection and Imaging.

Hypochlorite (ClO^-) has received extensive attention owing to its significant roles in the immune defense and pathogenesis of numerous diseases. However, excessive or misplaced production of ClO^- may pose certain diseases. Thus, to determine its biological functions in depth, ClO^- should be tested in biosystems. In this study, a facile, one-pot synthesis of nitrogen-fluorine-doped carbon quantum dots (N, F-CDs) was developed using ammonium citrate tribasic, L-alanine, and ammonium fluoride as raw materials under hydrothermal conditions. The prepared N, F-CDs demonstrate not only strong blue fluorescence emission with a high fluorescence quantum yield (26.3%) but also a small particle size of approximately 2.9 nm, as well as excellent water solubility and biocompatibility. Meanwhile, the as-prepared N, F-CDs exhibit good performance in the highly selective and sensitive detection of ClO^-. Thus, a wide concentration response range of 0-600 μM with a low limit of detection (0.75 μM) was favorably obtained for the N, F-CDs. Based on the excellent fluorescence stability, excellent water solubility, and low cell toxicity, the practicality and viability of the fluorescent composites were also successfully verified via detecting ClO^- in water samples and living RAW 264.7 cells. The proposed probe is expected to provide a new approach for detecting ClO^- in other organelles.