, Volume 12, Issue 2, pp 263–269 | Cite as

Strong Fluorescence Enhancement with Silica-Coated Au Nanoshell Dimers



Fluorescence intensity is vital for fluorescence sensing and imaging because it determines the sensing sensitivity and imaging brightness. This study reports plasmon-enhanced fluorescence by engineering plasmonic nanostructures, that are SiO2-coated Au nanoshell dimers with a high yield exceeding 60 %. With this elaborately designed nanostructure, we show that the thin SiO2 shell can conveniently distance the fluorophore from the underneath metal, thereby effectively avoiding fluorescence quenching. Meanwhile, the inner Au nanoshell dimers create abundant hot spots at particle-particle junctions and enable near-infrared fluorescence enhancement. The largest fluorescence enhancement achieved is 69 times for the design with a 9 nm external SiO2 shell, as is also confirmed by three-dimensional finite-difference time-domain simulations. This dramatically increased fluorescence has great significance in fluorescence-based sensing and imaging.


Au nanoshell Dimer Plasmon Fluorescence Metal-enhanced fluorescence 



The authors thank the financial supports from the National Natural Science Foundation of China (Grant Nos. 91027037 and 21173171) and Prof. Yan He for his kind assistance for obtaining the dark-field images in his lab.

Supplementary material

11468_2016_259_MOESM1_ESM.docx (3.2 mb)
ESM 1 (DOCX 3246 kb)


  1. 1.
    Chen LY, Wang CW, Chang HT et al (2015) Fluorescent gold nanoclusters: recent advances in sensing and imaging. Anal Chem 87(1):216–229CrossRefGoogle Scholar
  2. 2.
    Carter KP, Young AM, Palmer AE (2014) Fluorescent sensors for measuring metal ions in living systems. Chem Rev 114(8):4564–4601CrossRefGoogle Scholar
  3. 3.
    Domaille DW, Que EL, Chang CJ (2008) Synthetic fluorescent sensors for studying the cell biology of metals. Nat Chem Biol 4(3):168–175CrossRefGoogle Scholar
  4. 4.
    Medintz IL, Uyeda HT, Goldman ER et al (2005) Quantum dot bioconjugates for imaging, labelling and sensing. Nat Mater 4:435–446CrossRefGoogle Scholar
  5. 5.
    Liu HY, Wu PJ, Chan YH et al (2015) Quinoxaline-based polymer dots with ultrabright red to near-infrared fluorescence for in vivo biological imaging. J Am Chem Soc 137(32):10420–10429CrossRefGoogle Scholar
  6. 6.
    Liu W, Howarth M, Nocera DG et al (2008) Compact biocompatible quantum dots functionalized for cellular imaging. J Am Chem Soc 130(4):1274–1284CrossRefGoogle Scholar
  7. 7.
    Yan J, Wang K, Tan W et al (2007) Dye-doped nanoparticles for bioanalysis. Nano Today 2(3):44–50CrossRefGoogle Scholar
  8. 8.
    Wang K, He X, Shi H et al (2013) Functionalized silica nanoparticles: a platform for fluorescence imaging at the cell and small animal levels. Acc Chem Res 46(7):1367–1376CrossRefGoogle Scholar
  9. 9.
    Drexhage KH (1970) Influence of a dielectric interface on fluorescence decay time. J Lumin 1(2):693–701CrossRefGoogle Scholar
  10. 10.
    Ford GW, Weber WH (1981) Electromagnetic effects on a molecule at a metal surface 1. effects of nonlocality and finite molecular size. Surf Sci 109:451–481CrossRefGoogle Scholar
  11. 11.
    Geddes CD (2010) Metal-enhanced fluorescence. John Wiley & Sons, New JerseyCrossRefGoogle Scholar
  12. 12.
    Baker GA, Moore DS (2005) Progress in plasmonic engineering of surface-enhanced Raman-scattering substrates toward ultra-trace analysis. Anal Bioanal Chem 382(8):1751–1770CrossRefGoogle Scholar
  13. 13.
    Johansson P, Xu H, Käll M (2005) Surface-enhanced Raman scattering and fluorescence near metal nanoparticles. Phys Rev B 72(3):035427CrossRefGoogle Scholar
  14. 14.
    Li M, Cushing SK, Wu N (2015) Plasmon-enhanced optical sensors: a review. Analyst 140(2):386–406CrossRefGoogle Scholar
  15. 15.
    Li CY, Meng M, Huang SC et al (2015) “Smart” Ag nanostructures for plasmon-enhanced spectroscopies. J Am Chem Soc 137(43):13784–13787CrossRefGoogle Scholar
  16. 16.
    Wu K, Zhang J, Wang S et al (2015) Plasmon-enhanced fluorescence of PbS quantum dots for remote near-infrared imaging. Chem Commun 51(1):141–144CrossRefGoogle Scholar
  17. 17.
    Bardhan R, Grady NK, Cole JR et al (2009) Fluorescence enhancement by Au nanostructures: nanoshells and nanorods. ACS Nano 3(3):744–752CrossRefGoogle Scholar
  18. 18.
    Li C, Yang X, Li C et al (2014) Enhanced fluorescence of graphene oxide by well-controlled Au@SiO2 core-shell nanoparticles. J Fluoresc 24(1):137–141CrossRefGoogle Scholar
  19. 19.
    Bardhan R, Grady NK, Halas NJ (2008) Nanoscale control of near-infrared fluorescence enhancement using Au nanoshells. Small 4(10):1716–1722CrossRefGoogle Scholar
  20. 20.
    Liaw JW, Chen JH, Kuo MK et al (2009) Purcell effect of nanoshell dimer on single molecule’s fluorescence. Opt Express 17(16):13532–13540CrossRefGoogle Scholar
  21. 21.
    Aslan K, Wu M, Geddes CD et al (2007) Fluorescent core-shell Ag@SiO2 nanocomposites for metal-enhanced fluorescence and single nanoparticle sensing platforms. J Am Chem Soc 129(6):1524–1525CrossRefGoogle Scholar
  22. 22.
    Wang HS, Wang C, Zhou GJ et al (2014) Core-shell Ag@SiO2 nanoparticles concentrated on a micro/nanofluidic device for surface plasmon resonance-enhanced fluorescent detection of highly reactive oxygen species. Anal Chem 86(6):3013–3019CrossRefGoogle Scholar
  23. 23.
    Wosnick JH, Mello CM, Swager TM (2005) Synthesis and application of poly(phenylene ethynylene)s for bioconjugation: a conjugated polymer-based fluorogenic probe for proteases. J Am Chem Soc 127(10):3400–3405CrossRefGoogle Scholar
  24. 24.
    Lu L, Qian Y, Zhang Y et al (2014) Metal-enhanced fluorescence-based core-shell Ag@SiO2 nanoflares for affinity biosensing via target-induced structure switching of aptamer. ACS Appl Mater Interfaces 6(3):1944–1950CrossRefGoogle Scholar
  25. 25.
    Zhou JL, Zhang T, Hu JW et al (2015) Citrate-stabilized large Au nanoparticles: Seed-mediated synthesis and their size-optimized enhanced Raman at Pd overlayers. Chem Phys Lett 628:91–95CrossRefGoogle Scholar
  26. 26.
    Rodriguez-Fernandez J, Pérez-Juste J, Liz-Marzán LM et al (2006) Seeded growth of submicron Au colloids with quadrupole plasmon resonance modes. Langmuir 22(16):7007–7010CrossRefGoogle Scholar
  27. 27.
    Oldenburg SJ, Averitt RD, Halas NJ et al (1998) Nanoengineering of optical resonances. Chem Phys Lett 288:243–247CrossRefGoogle Scholar
  28. 28.
    Xu S, Hartvickson S, Zhao JX (2008) Engineering of SiO2-Au-SiO2 sandwich nanoaggregates using a building block: single, double, and triple cores for enhancement of near infrared fluorescence. Langmuir 24(14):7492–7499CrossRefGoogle Scholar
  29. 29.
    Wei Y, Cheng D, Ren T et al (2016) Design of NIR chromenylium-cyanine fluorophore library for “switch-on” and ratiometric detection of bio-active species in vivo. Anal Chem. doi: 10.1021/acs.analchem.5b04169 Google Scholar
  30. 30.
    Benson RC, Kues HA (1978) Fluorescence properties of indocyanine green as related to angiography. Phys Med Biol 23:159–163CrossRefGoogle Scholar
  31. 31.
    Stöber W, Fink A, Bohn E (1968) Controlled growth of monodisperse silica spheres in the micron size range. J Colloid Interface Sci 26:62–69CrossRefGoogle Scholar
  32. 32.
    Chen SL (1998) Preparation of monosize silica spheres and their crystalline stack. Colloid Surface A 142:59–63CrossRefGoogle Scholar
  33. 33.
    Graf C, Blaaderen V (2002) Metallodielectric colloidal core-shell particles for photonic applications. Langmuir 18(2):524–534CrossRefGoogle Scholar
  34. 34.
    Graf C, Vossen DLJ, Blaaderen V et al (2003) A general method to coat colloidal particles with silica. Langmuir 19(17):6693–6700CrossRefGoogle Scholar
  35. 35.
    Duff DG, Baiker A (1993) A new hydrosol of gold clusters. 1. Formation and particle size variation. Langmuir 9:2301–2309CrossRefGoogle Scholar
  36. 36.
    Luo CX, Cui Y, Hu JW et al (2014) Seed number density-controlled synthesis of Au@SiO2 nanoparticles. Chem J Chinese U 35(9):1948–1953Google Scholar
  37. 37.
    Birdi KS (2016) Handbook of surface and colloid chemistry. Taylor & Francis Group, CRC Press, Boca RatonGoogle Scholar
  38. 38.
    Smith JN, Meadows J, Williams PA (1996) Adsorption of polyvinylpyrrolidone onto polystyrene latices and the effect on colloid stability. Langmuir 12:3773–3778CrossRefGoogle Scholar
  39. 39.
    Lu Y, Yin YD, Xia YN et al (2002) Synthesis and self-assembly of Au@SiO2 core-shell colloids. Nano Lett 2(7):785–788CrossRefGoogle Scholar
  40. 40.
    Liz-Marzán LM, Giersig M, Mulvaney P (1996) Synthesis of nanosized gold-silica core-shell particles. Langmuir 12:4329–4335CrossRefGoogle Scholar
  41. 41.
    Im SH, Herricks T, Xia YN et al (2005) Synthesis and characterization of monodisperse silica colloids loaded with superparamagnetic iron oxide nanoparticles. Chem Phys Lett 401(1-3):19–23CrossRefGoogle Scholar
  42. 42.
    Yuan L, Lin W, Zhu S et al (2012) A unique approach to development of near-infrared fluorescent sensors for in vivo imaging. J Am Chem Soc 134(32):13510–13523CrossRefGoogle Scholar
  43. 43.
    Peng J, Xu W, Teoh CL et al (2015) High-efficiency in vitro and in vivo detection of Zn2+ by dye-assembled upconversion nanoparticles. J Am Chem Soc 137(6):2336–2342CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2016

Authors and Affiliations

  1. 1.State Key Laboratory of Chem/Biosensing and Chemometrics, College of Chemistry and Chemical EngineeringHunan UniversityChangshaPeople’s Republic of China
  2. 2.Department of PhysicsXiamen UniversityXiamenChina
  3. 3.Changsha Animal Disease Control CenterChangshaChina
  4. 4.Department of Chemistry and BiochemistryUniversity of CaliforniaLos AngelesUSA

Personalised recommendations