Analytical and Bioanalytical Chemistry

, Volume 411, Issue 8, pp 1647–1657 | Cite as

Multifunctional N,S co-doped carbon dots for sensitive probing of temperature, ferric ion, and methotrexate

  • Pengli ZuoEmail author
  • Jianhua Liu
  • Hongna Guo
  • Chenghong Wang
  • Hongqian Liu
  • Zhigang Zhang
  • Qingyou Liu
Research Paper


In this paper, we have presented a facile method to fabricate nitrogen and sulfur co-doped carbon dots (N,S-CDs) for blood methotrexate (MTX) sensing applications. The N,S-CDs with quantum yield up to 75% were obtained by one-step hydrothermal carbonization, using reduced glutathione and citric acid as the precursors. With this approach, the formation and the surface passivation of N,S-CDs were carried out simultaneously, resulting in intrinsic fluorescence emission. Owing to their pronounced temperature dependence of the fluorescence emission spectra, resultant N,S-CDs can work as versatile nanothermometry devices by taking advantage of the temperature sensitivity of their emission intensity. In addition, the obtained N,S-CDs facilitated high selectivity detection of Fe3+ ions with a detection limit as low as 0.31 μM and a wide linear range from 3.33 to 99.90 μM. More importantly, the added MTX selectively led to the fluorescence quenching of the N,S-CDs. Such fluorescence responses were used for well quantifying MTX in the range of 2.93 to 117.40 μM, and the detection limit was down to 0.95 μM. Due to “inert” surface, the N,S-CDs well resisted the interferences from various biomolecules and exhibited excellent selectivity. The proposed sensing system was successfully used for the assay of MTX in human plasma. Due to simplicity, sensitivity, selectivity, and low cost, it exhibits great promise as a practical platform for MTX sensing in biological samples.

Graphical Abstract


Doped carbon dots Multifunctional probe Hydrothermal carbonization Excitation-independent emission Surface passivation Methotrexate 



This work was supported by the Key Research & Development Program of Shandong Province (2018GGX109006), Independent Innovation Fund Project of Agricultural Science and Technology of Jiangsu Province in 2017 (No.CX (17)1003), and China Scholarship Council.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflicts of interests.

Ethical standards and informed consent

Whole blood sample was collected from a healthy volunteer in Linyi Central Hospital and informed consent was obtained for the use of human blood. This research was approved by Linyi Central Hospital Ethic Committee and all experiments were performed in accordance with the Guideline for Experimentation of Linyi Central Hospital.

Supplementary material

216_2019_1617_MOESM1_ESM.pdf (370 kb)
ESM 1 (PDF 369 kb)


  1. 1.
    Schmiegelow K. Advances in individual prediction of methotrexate toxicity: a review. Br J Haematol. 2009;146:489–503.CrossRefPubMedGoogle Scholar
  2. 2.
    Merás ID, Mansilla AE, Gómez MJR. Determination of methotrexate, several pteridines, and creatinine in human urine, previous oxidation with potassium permanganate, using HPLC with photometric and fluorimetric serial detection. Anal Biochem. 2005;346:201–9.CrossRefGoogle Scholar
  3. 3.
    Mendu DR, Chou PP, Soldin SJ. An improved application for the enzyme multipled immunoassay technique for caffeine, amikacin, and methotrexate assays on the Dade-Behring Dimension RxL Max clinical chemistry system. Ther Drug Monit. 2007;29:632–7.CrossRefPubMedGoogle Scholar
  4. 4.
    Ananthanarayanan A, Wang X, Routh P, Sana B, Lim S, Kim DH, et al. Facile synthesis of graphene quantum dots from 3D graphene and their application for Fe3+ sensing. Adv Funct Mater. 2014;24:3021–6.CrossRefGoogle Scholar
  5. 5.
    Zhang S, Li J, Zeng M, Xu J, Wang X, Hu W. Polymer nanodots of graphitic carbon nitride as effective fluorescent probes for the detection of Fe3+ and Cu2+ ions. Nanoscale. 2014;6:4157–62.CrossRefPubMedGoogle Scholar
  6. 6.
    Sahoo SK, Sharma D, Bera RK, Crisponi G, Callan JF. Iron (III) selective molecular and supramolecular fluorescent probes. Chem Soc Rev. 2012;41:7195–227.CrossRefPubMedGoogle Scholar
  7. 7.
    Kuwar A, Patil R, Singh A, Sahoo SK, Marek J, Singh N. A two-in-one dual channel chemosensor for Fe3+ and Cu2+ with nanomolar detection mimicking the IMPLICATION logic gate. J Mater Chem C. 2015;3:453–60.CrossRefGoogle Scholar
  8. 8.
    Sahoo SK, Sharma D, Moirangthem A, Kuba A, Thomas R, Kumar R, et al. Pyridoxal derived chemosensor for chromogenic sensing of Cu2+ and fluorogenic sensing of Fe3+ in semi-aqueous medium. J Lumin. 2016;172:297–303.CrossRefGoogle Scholar
  9. 9.
    Upadhyay Y, Anand T, Babu LT, Paira P, SK AK, Kumar R, et al. Combined use of spectrophotometer and smartphone for the optical detection of Fe3+ using a vitamin B6 cofactor conjugated pyrene derivative and its application in live cells imaging. J Photochem Photobiol A Chem. 2018;361:34–40.CrossRefGoogle Scholar
  10. 10.
    Zhang H, Chen Y, Liang M, Xu L, Qi S, Chen H, et al. Solid-phase synthesis of highly fluorescent nitrogen-doped carbon dots for sensitive and selective probing ferric ions in living cells. Anal Chem. 2014;86:9846–52.CrossRefPubMedGoogle Scholar
  11. 11.
    Jia X, Li J, Wang E. One-pot green synthesis of optically pH-sensitive carbon dots with upconversion luminescence. Nanoscale. 2012;4:5572–5.CrossRefPubMedGoogle Scholar
  12. 12.
    Zhou J, Zhou H, Tang J, Deng S, Yan F, Li W, et al. Carbon dots doped with heteroatoms for fluorescent bioimaging: a review. Microchim Acta. 2017;184:343–68.CrossRefGoogle Scholar
  13. 13.
    Liu Q, Guo B, Rao Z, Zhang B, Gong JR. Strong two-photon-induced fluorescence from photostable, biocompatible nitrogen-doped graphene quantum dots for cellular and deep-tissue imaging. Nano Lett. 2013;13:2436–41.CrossRefGoogle Scholar
  14. 14.
    Sekiya R, Uemura Y, Murakami H, Haino T. White-light-emitting edge-functionalized graphene quantum dots. Angew Chem Int Ed. 2014;53:5619–23.CrossRefGoogle Scholar
  15. 15.
    Liu J, Liu Y, Liu N, Han Y, Zhang X, Huang H, et al. Metal-free efficient photocatalyst for stable visible water splitting via a two-electron pathway. Science. 2015;347:970–4.CrossRefPubMedGoogle Scholar
  16. 16.
    Jiang K, Sun S, Zhang L, Lu Y, Wu A, Cai C, et al. Red, green, and blue luminescence by carbon dots: full-color emission tuning and multicolor cellular imaging. Angew Chem Int Ed. 2015;54:5360–3.CrossRefGoogle Scholar
  17. 17.
    Briscoe J, Marinovic A, Sevilla M, Dunn S, Titirici M. Biomass-derived carbon quantum dot sensitizers for solid-state nanostructured solar cells. Angew Chem Int Ed. 2015;54:4463–8.CrossRefGoogle Scholar
  18. 18.
    Yang Z, Xu M, Liu Y, He F, Gao F, Su Y, et al. Nitrogen-doped, carbon-rich, highly photoluminescent carbon dots from ammonium citrate. Nanoscale. 2014;6:1890–5.CrossRefPubMedGoogle Scholar
  19. 19.
    Ding H, Wei JS, Xiong HM. Nitrogen and sulfur co-doped carbon dots with strong blue luminescence. Nanoscale. 2014;6:13817–23.CrossRefPubMedGoogle Scholar
  20. 20.
    Dong Y, Pang H, Yang HB, Guo C, Shao J, Chi Y, et al. Carbon-based dots co-doped with nitrogen and sulfur for high quantum yield and excitation-independent emission. Angew Chem Int Ed. 2013;52:7800–4.CrossRefGoogle Scholar
  21. 21.
    Song Z, Quan F, Xu Y, Liu M, Cui L, Liu J. Multifunctional N, S co-doped carbon quantum dots with pH-and thermo-dependent switchable fluorescent properties and highly selective detection of glutathione. Carbon. 2016;104:169–78.CrossRefGoogle Scholar
  22. 22.
    Shi W, Guo F, Han M, Yuan S, Guan W, Li H, et al. N, S co-doped carbon dots as a stable bio-imaging probe for detection of intracellular temperature and tetracycline. J Mater Chem B. 2017;5:3293–9.CrossRefGoogle Scholar
  23. 23.
    Lu YC, Chen J, Wang AJ, Bao N, Feng JJ, Wang W, et al. Facile synthesis of oxygen and sulfur co-doped graphitic carbon nitride fluorescent quantum dots and their application for mercury (II) detection and bioimaging. J Mater Chem C. 2015;3:73–8.CrossRefGoogle Scholar
  24. 24.
    Wang Y, Zhuang Q, Ni Y. Facile microwave-assisted solid-phase synthesis of highly fluorescent nitrogen-sulfur-codoped carbon quantum dots for cellular imaging applications. Chem Eur J. 2015;21:13004–11.CrossRefPubMedGoogle Scholar
  25. 25.
    Zhou J, Booker C, Li R, Zhou X, Sham TK, Sun X, et al. An electrochemical avenue to blue luminescent nanocrystals from multiwalled carbon nanotubes (MWCNTs). J Am Chem Soc. 2007;129:744–5.CrossRefGoogle Scholar
  26. 26.
    Lim SY, Shen W, Gao Z. Carbon quantum dots and their applications. Chem Soc Rev. 2015;44:362–81.CrossRefGoogle Scholar
  27. 27.
    Qu D, Zheng M, Du P, Zhou Y, Zhang L, Li D, et al. Highly luminescent S, N co-doped graphene quantum dots with broad visible absorption bands for visible light photocatalysts. Nanoscale. 2013;5:12272–7.CrossRefGoogle Scholar
  28. 28.
    Chen M, Wang W, Wu X. One-pot green synthesis of water-soluble carbon nanodots with multicolor photoluminescence from polyethylene glycol. J Mater Chem B. 2014;2:3937–45.CrossRefGoogle Scholar
  29. 29.
    Qin Z, Wang W, Zhan X, Du X, Zhang Q, Zhang R, et al. One-pot synthesis of dual carbon dots using only an N and S co-existed dopant for fluorescence detection of Ag+. Spectrochim Acta A Mol Biomol Spectrosc. 2019;208:162–71.CrossRefPubMedGoogle Scholar
  30. 30.
    Ding H, Yu SB, Wei JS, Xiong HM. Full-color light-emitting carbon dots with a surface-state-controlled luminescence mechanism. ACS Nano. 2016;10:484–91.CrossRefPubMedGoogle Scholar
  31. 31.
    Tang L, Ji R, Cao X, Lin J, Jiang H, Li X, et al. Deep ultraviolet photoluminescence of water-soluble self-passivated graphene quantum dots. ACS Nano. 2012;6:5102–10.CrossRefGoogle Scholar
  32. 32.
    Baker SN, Baker GA. Luminescent carbon nanodots: emergent nanolights. Angew Chem Int Ed. 2010;49:6726–44.CrossRefGoogle Scholar
  33. 33.
    Xue M, Zhang L, Zou M, Lan C, Zhan Z, Zhao S. Nitrogen and sulfur co-doped carbon dots: a facile and green fluorescence probe for free chlorine. Sensors Actuators B Chem. 2015;219:50–6.CrossRefGoogle Scholar
  34. 34.
    Yu J, Song N, Zhang YK, Zhong SX, Wang AJ, Chen J. Green preparation of carbon dots by Jinhua bergamot for sensitive and selective fluorescent detection of Hg2+ and Fe3+. Sensors Actuators B Chem. 2015;214:29–35.CrossRefGoogle Scholar
  35. 35.
    Wu H, Jiang J, Gu X, Tong C. Nitrogen and sulfur co-doped carbon quantum dots for highly selective and sensitive fluorescent detection of Fe (III) ions and L-cysteine. Microchim Acta. 2017;184:2291–8.CrossRefGoogle Scholar
  36. 36.
    Cui X, Wang Y, Liu J, Yang Q, Zhang B, Gao Y, et al. Dual functional N- and S-co-doped carbon dots as the sensor for temperature and Fe3+ ions. Sensors Actuators B Chem. 2017;242:1272–80.CrossRefGoogle Scholar
  37. 37.
    Yu P, Wen X, Toh YR, Tang J. Temperature-dependent fluorescence in carbon dots. J Phys Chem C. 2012;116:25552–7.CrossRefGoogle Scholar
  38. 38.
    Hu Y, Yang J, Jia L, Yu JS. Ethanol in aqueous hydrogen peroxide solution: hydrothermal synthesis of highly photoluminescent carbon dots as multifunctional nanosensors. Carbon. 2015;93:999–1007.CrossRefGoogle Scholar
  39. 39.
    Zhu S, Meng Q, Wang L, Zhang J, Song Y, Jin H, et al. Highly photoluminescent carbon dots for multicolor patterning, sensors, and bioimaging. Angew Chem. 2013;125:4045–9.CrossRefGoogle Scholar
  40. 40.
    Zhao A, Zhao C, Li M, Ren J, Qu X. Ionic liquids as precursors for highly luminescent, surface-different nitrogen-doped carbon dots used for label-free detection of Cu2+/Fe3+ and cell imaging. Anal Chim Acta. 2014;809:128–33.CrossRefPubMedGoogle Scholar
  41. 41.
    Zhu X, Wang J, Zhu Y, Jiang H, Tan D, Xu Z, et al. Green emitting N,S-co-doped carbon dots for sensitive fluorometric determination of Fe (III) and Ag (I) ions, and as a solvatochromic probe. Microchim Acta. 2018;185:510.CrossRefGoogle Scholar
  42. 42.
    Liu G, Li S, Cheng M, Zhao L, Zhang B, Gao Y, et al. Facile synthesis of nitrogen and sulfur co-doped carbon dots for multiple sensing capacities: alkaline fluorescence enhancement effect, temperature sensing, and selective detection of Fe3+ ions. New J Chem. 2018;42:13147–56.CrossRefGoogle Scholar
  43. 43.
    Zuo P, Xiao D, Gao M, Peng J, Pan R, Xia Y, et al. Single-step preparation of fluorescent carbon nanoparticles, and their application as a fluorometric probe for quercetin. Microchim Acta. 2014;181:1309–16.CrossRefGoogle Scholar
  44. 44.
    Shen P, Xia Y. Synthesis-modification integration: one-step fabrication of boronic acid functionalized carbon dots for fluorescent blood sugar sensing. Anal Chem. 2014;86:5323–9.CrossRefPubMedGoogle Scholar
  45. 45.
    Cheng HL, Chiou SS, Liao YM, Lu CY, Chen YL, Wu SM. Analysis of methotrexate and its eight metabolites in cerebrospinal fluid by solid-phase extraction and triple-stacking capillary electrophoresis. Anal Bioanal Chem. 2010;398:2183–90.CrossRefPubMedGoogle Scholar
  46. 46.
    Rule G, Chapple M, Henion J. A 384-well solid-phase extraction for LC/MS/MS determination of methotrexate and its 7-hydroxy metabolite in human urine and plasma. Anal Chem. 2001;73:439–43.CrossRefPubMedGoogle Scholar
  47. 47.
    Subaihi A, Trivedi DK, Hollywood KA, Bluett J, Xu Y, Muhamadali H, et al. Quantitative online liquid chromatography-surface-enhanced raman scattering (LC-SERS) of methotrexate and its major metabolites. Anal Chem. 2017;89:6702–9.CrossRefPubMedGoogle Scholar
  48. 48.
    Zhao Y, Zou S, Huo D, Hou C, Yang M, Li J, et al. Simple and sensitive fluorescence sensor for methotrexate detection based on the inner filter effect of N, S co-doped carbon quantum dots. Anal Chim Acta. 2019;1047:179–87.CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Pengli Zuo
    • 1
    • 2
    Email author
  • Jianhua Liu
    • 1
  • Hongna Guo
    • 1
  • Chenghong Wang
    • 1
  • Hongqian Liu
    • 1
  • Zhigang Zhang
    • 1
  • Qingyou Liu
    • 3
  1. 1.Central LaboratoryLinyi Central HospitalLinyiChina
  2. 2.Ilse Katz Institute for NanotechnologyBen Gurion University of the NegevBeer ShevaIsrael
  3. 3.Linyi Center for Disease Prevention and ControlLinyiChina

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