Green-emissive carbon quantum dots with high fluorescence quantum yield: Preparation and cell imaging

Abstract

High fluorescence quantum yield (QY), excellent fluorescence stability, and low toxicity are essential for a good cellular imaging fluorescent probe. Green-emissive carbon quantum dots (CQDs) with many advantages, such as unique fluorescence properties, anti-photobleaching, low toxicity, fine biocompatibility and high penetration depth in tissues, have been considered as a potential candidate in cell imaging fluorescent probes. Herein, N, S-codoped green-emissive CQDs (QY= 64.03%) were synthesized by the one-step hydrothermal method, with m-phenylenediamine as the carbon and nitrogen source, and L-cysteine as the nitrogen and sulfur dopant, under the optimum condition of 200 °C reaction for 2 h. Their luminescence was found to originate from the surface state. In light of the satisfactory photobleaching resistance and the low cytotoxicity, CQDs were used as a cell imaging probe for HeLa cell imaging. The results clearly indicate that cells can be labeled with CQDs, which can not only enter the cytoplasm, but also enter the nucleus through the nuclear pore, showing their broad application prospect in the field of cell imaging.

Graphical abstract

Keywords

fluorescence quantum yield / green emission / carbon quantum dot / N, S-codoping / cell imaging

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Disclosure of potential conflicts of interests

The authors declare no conflict of interest.

Acknowledgements

This work was supported by the National Natural Science Foundation of China (Grant Nos. 51972221 and 51803148), Central Government Guides Local Science and Technology Development Projects (YDZX20201400001722), the Shanxi Provincial Excellent Talents Science and Technology Innovation Project (201805D211001), and the Natural Science Foundation of Shanxi Province (201901D211502 and 201901D211501).

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