Microchimica Acta

, Volume 183, Issue 2, pp 581–588 | Cite as

Silica-coated carbon dots conjugated to CdTe quantum dots: a ratiometric fluorescent probe for copper(II)

  • Hanbing RaoEmail author
  • Wei Liu
  • Zhiwei Lu
  • Yanying WangEmail author
  • Hongwei Ge
  • Ping Zou
  • Xianxiang Wang
  • Hua He
  • Xianying Zeng
  • Yongjia Wang
Original Paper


The surface of CdTe quantum dots (Q-dots) was modified with thioglycolic acid (TGA) and these Q-dots were then covalently conjugated to amino-functionalized silica-coated carbon dots (C-dot@SiO2) via carbodiimide chemistry. The Q-dots form kind of “satellites” on the surface of the C-dot@SiO2 nanoparticles. The nanoparticle conjugates display dual emission (with peaks at 441 nm and 605 nm) under UV excitation and were further characterized by transmission electron microscopy, UV–vis absorption and FTIR spectroscopy. The C-dot@SiO2@Q-dots hybrid spheres are shown to represent a ratiometric fluorescent probe for Cu2+ in that the emission of the Q-dots is quenched by Cu2+, while the emission of the C-dots (which are coated with SiO2) is not quenched. The ratio of the fluorescence intensities at 441 and 655 nm is related to the concentration of Cu2+ in the range from 0.1 to 1.0 μM, with a 0.096 μM lower detection limit. The ratiometric probe was successfully applied to the determination of Cu2+ in (spiked) vegetable and fruit samples by the standard addition method, and recoveries ranged from 96.7 to 100.8 %.

Graphical Abstract

Carbon dots were first coated with silica and then with CdTe quantum dots to give nanoparticles with an architecture of the type C-dot@SiO2@Q-dots. These are shown to be a viable ratiometric fluorescent probe for the detection of Cu(II).


C-dot@SiO2@Q-dots hybrid spheres Carbodiimide chemistry Dual emission TEM DLS Quenching 



This work was supported by a grant from the Two-Way Support Programs of Sichuan Agricultural University (Project No.03570113), the Education Department of Sichuan Provincial, PR China (Grant Nos. 13ZA0255).

Supplementary material

604_2015_1682_MOESM1_ESM.doc (246 kb)
ESM 1 (DOC 246 kb)


  1. 1.
    Miao X, Ling L, Cheng D, Shuai X (2012) A highly sensitive sensor for Cu2+ with unmodified gold nanoparticles and DNAzyme by using the dynamic light scattering technique. Analyst 137(13):3064–3069CrossRefGoogle Scholar
  2. 2.
    Yu M, Shi M, Chen Z, Li F, Li X, Gao Y, Xu J, Yang H, Zhou Z, Yi T, Huang C (2008) Highly sensitive and fast responsive fluorescence turn-on chemodosimeter for Cu2+ and its application in live cell imaging. Chem Eur J 14(23):6892–6900CrossRefGoogle Scholar
  3. 3.
    Zong J, Yang X, Trinchi A, Hardin S, Cole I, Zhu Y, Li C, Muster T, Wei G (2014) Carbon dots as fluorescent probes for “off-on” detection of Cu2+ and L-cysteine in aqueous solution. Biosensor Bioelectron 51:330–335CrossRefGoogle Scholar
  4. 4.
    Li F, Wang J, Lai Y, Wu C, Sun S, He Y, Ma H (2013) Ultrasensitive and selective detection of copper (II) and mercury (II) ions by dye-coded silver nanoparticle-based SERS probes. Biosens Bioelectron 39(1):82–87CrossRefGoogle Scholar
  5. 5.
    Liu J, Lu Y (2007) Colorimetric Cu2+ detection with a ligation DNAzyme and nanoparticles. Chem Commun (46):4872–4874Google Scholar
  6. 6.
    Jung HS, Kwon PS, Lee JW, Kim JI, Hong CS, Kim JW, Yan S, Lee JY, Lee JH, Joo T, Kim JS (2009) Coumarin-derived Cu2+ −selective fluorescence sensor: synthesis, mechanisms, and applications in living cells. J Am Chem Soc 131(5):2008–2012CrossRefGoogle Scholar
  7. 7.
    Hao Y, Liu L, Long Y, Wang J, Liu Y-N, Zhou F (2013) Sensitive photoluminescent detection of Cu2+ in real samples using CdS quantum dots in combination with a Cu2+ −reducing reaction. Biosens Bioelectron 41:723–729CrossRefGoogle Scholar
  8. 8.
    Li H, Huang X-X, Kong D-M, Shen H-X, Liu Y (2013) Ultrasensitive, high temperature and ionic strength variation-tolerant Cu2+ fluorescent sensor based on reconstructed Cu2+ −dependent DNAzyme/substratecomplex. Biosens Bioelectron 42:225–228CrossRefGoogle Scholar
  9. 9.
    Su L, Shu T, Wang Z, Cheng J, Xue F, Li C, Zhang X (2013) Immobilization of bovine serum albumin-protected gold nanoclusters by using polyelectrolytes of opposite charges for the development of the reusable fluorescent Cu2+ −sensor. Biosens Bioelectron 44:16–20CrossRefGoogle Scholar
  10. 10.
    Wang Y-Q, Zhao T, He X-W, Li W-Y, Zhang Y-K (2014) A novel core-satellite CdTe/Silica/Au NCs hybrid sphere as dual-emission ratiometric fluorescent probe for Cu2+. Biosens Bioelectron 51:40–46CrossRefGoogle Scholar
  11. 11.
    Zhu A, Qu Q, Shao X, Kong B, Tian Y (2012) Carbon-dot-based dual-emission nanohybrid produces a ratiometric fluorescent sensor for in vivo imaging of cellular copper ions. Angew Chem 124(29):7297–7301CrossRefGoogle Scholar
  12. 12.
    Ghaedi M, Ahmadi F, Shokrollahi A (2007) Simultaneous preconcentration and determination of copper, nickel, cobalt and lead ions content by flame atomic absorption spectrometry. J Hazard Mater 142(1):272–278CrossRefGoogle Scholar
  13. 13.
    Tao G-H, Sturgeon R (1999) Sample nebulization for minimization of transition metal interferences with selenium hydride generation ICP-AES. Spectrochim Acta B At Spectrosc 54(3):481–489CrossRefGoogle Scholar
  14. 14.
    Li X-A, Zhou D-M, Xu J-J, Chen H-Y (2007) In-channel indirect amperometric detection of heavy metal ions for electrophoresis on a poly (dimethylsiloxane) microchip. Talanta 71(3):1130–1135CrossRefGoogle Scholar
  15. 15.
    Rahman MA, Won M-S, Shim Y-B (2003) Characterization of an EDTA bonded conducting polymer modified electrode: its application for the simultaneous determination of heavy metal ions. Anal Chem 75(5):1123–1129CrossRefGoogle Scholar
  16. 16.
    Zhang S, Wang Q, Tian G, Ge H (2014) A fluorescent turn-off/on method for detection of Cu2+ and oxalate using carbon dots as fluorescent probes in aqueous solution. Mater Lett 115:233–236Google Scholar
  17. 17.
    Durgadas C, Sharma C, Sreenivasan K (2011) Fluorescent gold clusters as nanosensors for copper ions in live cells. Analyst 136(5):933–940CrossRefGoogle Scholar
  18. 18.
    Wang H-H, Xue L, Qian Y-Y, Jiang H (2009) Novel ratiometric fluorescent sensor for silver ions. Org Lett 12(2):292–295CrossRefGoogle Scholar
  19. 19.
    Yao J, Zhang K, Zhu H, Ma F, Sun M, Yu H, Sun J, Wang S (2013) Efficient ratiometric fluorescence probe based on dual-emission quantum dots hybrid for on-site determination of copper ions. Anal Chem 85(13):6461–6468CrossRefGoogle Scholar
  20. 20.
    Zhang K, Zhou H, Mei Q, Wang S, Guan G, Liu R, Zhang J, Zhang Z (2011) Instant visual detection of trinitrotoluene particulates on various surfaces by ratiometric fluorescence of dual-emission quantum dots hybrid. J Am Chem Soc 133(22):8424–8427CrossRefGoogle Scholar
  21. 21.
    Yang Y, Ji S, Zhou F, Zhao J (2009) Synthesis of novel bispyrene diamines and their application as ratiometric fluorescent probes for detection of DNA. Biosens Bioelectron 24(12):3442–3447CrossRefGoogle Scholar
  22. 22.
    Su T, Zhang Z, Luo Q (2012) Ratiometric fluorescence imaging of dual bio-molecular events in single living cells using a new FRET pair mVenus/mKOκ-based biosensor and a single fluorescent protein biosensor. Biosens Bioelectron 31(1):292–298CrossRefGoogle Scholar
  23. 23.
    Li P, Fang L, Zhou H, Zhang W, Wang X, Li N, Zhong H, Tang B (2011) A new ratiometric fluorescent probe for detection of Fe2+ with high sensitivity and its intracellular imaging applications. Chem Eur J 17(38):10520–10523CrossRefGoogle Scholar
  24. 24.
    Wu H, Mi C, Huang H, Han B, Li J, Xu S (2012) Solvothermal synthesis of green-fluorescent carbon nanoparticles and their application. J Lumin 132(6):1603–1607CrossRefGoogle Scholar
  25. 25.
    Bao L, Zhang ZL, Tian ZQ, Zhang L, Liu C, Lin Y, Qi B, Pang DW (2011) Electrochemical tuning of luminescent carbon nanodots: from preparation to luminescence mechanism. Adv Mater 23(48):5801–5806CrossRefGoogle Scholar
  26. 26.
    Yang Y, Chen O, Angerhofer A, Cao YC (2006) Radial-position-controlled doping in CdS/ZnS core/shell nanocrystals. J Am Chem Soc 128(38):12428–12429CrossRefGoogle Scholar
  27. 27.
    Wang J, Chen G, Jiang H, Li Z, Wang X (2013) Advances in nano-scaled biosensors for biomedical applications. Analyst 138(16):4427–4435CrossRefGoogle Scholar
  28. 28.
    Zhu S, Meng Q, Wang L, Zhang J, Song Y, Jin H, Zhang K, Sun H, Wang H, Yang B (2013) Highly photoluminescent carbon dots for multicolor patterning, sensors, and bioimaging. Angew Chem 125(14):4045–4049CrossRefGoogle Scholar
  29. 29.
    Jin SH, Kim DH, Jun GH, Hong SH, Jeon S (2013) Tuning the photoluminescence of graphene quantum dots through the charge transfer effect of functional groups. ACS Nano 7(2):1239–1245CrossRefGoogle Scholar
  30. 30.
    Tetsuka H, Asahi R, Nagoya A, Okamoto K, Tajima I, Ohta R, Okamoto A (2012) Optically tunable amino-functionalized graphene quantum dots. Adv Mater 24(39):5333–5338CrossRefGoogle Scholar
  31. 31.
    Hu S, Tian R, Dong Y, Yang J, Liu J, Chang Q (2013) Modulation and effects of surface groups on photoluminescence and photocatalytic activity of carbon dots. Nanoscale 5(23):11665–11671CrossRefGoogle Scholar
  32. 32.
    Jing L, Yang C, Qiao R, Niu M, Du M, Wang D, Gao M (2009) Highly fluorescent CdTe@ SiO2 particles prepared via reverse microemulsion method. Chem Mater 22(2):420–427CrossRefGoogle Scholar
  33. 33.
    Bagwe RP, Hilliard LR, Tan W (2006) Surface modification of silica nanoparticles to reduce aggregation and nonspecific binding. Langmuir 22(9):4357–4362CrossRefGoogle Scholar
  34. 34.
    Shi Y, Chen Z, Cheng X, Pan Y, Zhang H, Zhang Z, Li C-W, Yi C (2014) A novel dual-emission ratiometric fluorescent nanoprobe for sensing and intracellular imaging of Zn 2+. Biosens Bioelectron 61:397–403CrossRefGoogle Scholar
  35. 35.
    Feng C, Shen Z, Li Y, Gu L, Zhang Y, Lu G, Huang X (2009) PNIPAM-b-(PEA-g-PDMAEA) double-hydrophilic graft copolymer: synthesis and its application for preparation of gold nanoparticles in aqueous media. J Polym Sci Part A: Polym Chem 47(7):1811–1824CrossRefGoogle Scholar
  36. 36.
    Wang F, Xie Z, Zhang H, Liu CY, Zhang YG (2011) Highly luminescent organosilane functionalized carbon dots. Adv Funct Mater 21(6):1027–1031CrossRefGoogle Scholar
  37. 37.
    Dong Y, Wang R, Li G, Chen C, Chi Y, Chen G (2012) Polyamine-functionalized carbon quantum dots as fluorescent probes for selective and sensitive detection of copper ions. Anal Chem 84(14):6220–6224CrossRefGoogle Scholar
  38. 38.
    Koneswaran M, Narayanaswamy R (2009) L-Cysteine-capped ZnS quantum dots based fluorescence sensor for Cu2+ ion. Sensors Actuators B Chem 139(1):104–109CrossRefGoogle Scholar
  39. 39.
    Zhang J, Li B, Zhang L, Jiang H (2012) An optical sensor for Cu (II) detection with upconverting luminescent nanoparticles as an excitation source. Chem Commun 48(40):4860–4862CrossRefGoogle Scholar
  40. 40.
    Gattás-Asfura K M, Leblanc R M (2003) Peptide-coated CdS quantum dots for the optical detection of copper (II) and silver (I). Chem Commun (21) 2684–2685Google Scholar

Copyright information

© Springer-Verlag Wien 2015

Authors and Affiliations

  • Hanbing Rao
    • 1
  • Wei Liu
    • 1
  • Zhiwei Lu
    • 1
  • Yanying Wang
    • 1
  • Hongwei Ge
    • 1
  • Ping Zou
    • 1
  • Xianxiang Wang
    • 1
  • Hua He
    • 2
  • Xianying Zeng
    • 3
  • Yongjia Wang
    • 4
  1. 1.College of ScienceSichuan Agricultural UniversityYa’anPeople’s Republic of China
  2. 2.Animal Genetics and Breeding Institute of Sichuan Agricultural UniversitySichuan Ya’AnPeople’s Republic of China
  3. 3.College of Life ScienceSichuan Agricultural UniversityYa’anPeople’s Republic of China
  4. 4.Ya’an City Agricultural Products QualitySafety Monitoring and Testing CenterYa’anPeople’s Republic of China

Personalised recommendations