Chemical Research in Chinese Universities ›› 2020, Vol. 36 ›› Issue (5): 955-961.doi: 10.1007/s40242-020-0015-4

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Deep Eutectic Solvent-assisted Synthesis of Nitrogen-doped Carbon Quantum Dots for Cell Imaging

LI Long, HUANG Yan, ZHAO Pei, MIAO Haochi, ZHAO Ting   

  1. School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013, P. R. China
  • Received:2020-01-17 Revised:2020-03-17 Online:2020-10-01 Published:2020-10-01
  • Contact: HUANG Yan E-mail:huangyan2013@ujs.edu.cn
  • Supported by:
    Supported by the National Natural Science Foundation of China(No.21601068) and the Scientific Research Foundation for Advanced Talents of Jiangsu University, China(No.14JDG054).

Abstract: Carbon quantum dots(CQDs) are widely used in fluorescence imaging due to their negligible toxicity, low-cost and excellent fluorescence properties. The fluorescence properties of CQDs are greatly affected by the synthesis method, passivation agent and reaction media. In this study, the nitrogen-doped CQDs(N-CQDs) were synthesized by a facile microwave-assisted method with citric acid(CA) as a carbon source and deep eutectic solvents as a N-dopant as well as the reaction solvent. After detailed characterizations, the as-prepared N-CQDs exhibited near spherical morphology with an average size of (2.64±0.55) nm. Besides, the abundant hydrophilic functional groups including hydroxyl, carboxyl, amine and quaternary ammonium were present on the surface of the N-CQDs. The N-CQDs displayed the excitation-dependent fluorescence feature under the excitation wavelength of 350-480 nm. Moreover, the N-CQDs could be efficiently uptaken by RAW264.7 cells and emitted bright green light. Meanwhile, the resultant N-CQDs showed the low cytotoxicity in living cells, suggesting the great potential in bio-imaging applications.

Key words: N-Dopant carbon quantum dot, Microwave, Deep eutectic solvent, Green light emission, Cell imaging