Functionalized carbon quantum dots as fluorescent nanoprobe for determination of tetracyclines and cell imaging


Nitrogen and sulfur co-doped carbon dots (N, S-CQDs) with high fluorescent, water-soluble, low-toxicity properties were synthesized by microwave-assisted hydrothermal approach. The prepared N, S-CDs exhibited high selectivity in detection of tetracyclines (TCs) and displayed a fast-responsive fluorescence quenching signal in the mixture, which are mainly attributed to the inner filter effect (IFE). The synthesized N, S-CQDs are successfully used as a fluorescent nanoprobe for the determination of CTC in milk samples (with excitation/emission maxima at 373/424 nm). The limit of detection (LOD) is 71 ng mL−1, and the recoveries of spiked samples range from 96 to 104% with a relative standard deviations (RSDs) less than 2.7% (n = 3). Additionally, the cytotoxicity and optical imaging performance of N, S-CQDs were preliminarily evaluated. The results indicate the low-toxicity and good biocompatibility of the N, S-CQDs and their promising future as fluorescent-imaging agents in pharmaceutical analysis.

Synthesis flowchart and application of nitrogen and sulfur dual-doped carbon quantum dots.

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Correspondence to Longshan Zhao.

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Zhao, N., Wang, Y., Hou, S. et al. Functionalized carbon quantum dots as fluorescent nanoprobe for determination of tetracyclines and cell imaging. Microchim Acta 187, 351 (2020).

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  • S-CQDs
  • Fluorescence assay
  • Quenching
  • Bioimage
  • Inner filter effect