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Figures of Merit for Refractometric LSPR Biosensing

  • Marinus A. Otte
  • Borja SepulvedaEmail author
Chapter
Part of the Integrated Analytical Systems book series (ANASYS)

Abstract

The aim of this chapter is to describe routes to improve the features of plasmonic nanoparticles as refractometric based biosensors. Taking advantage of the tunability of their localized surface plasmon resonance (LSPR), we explore the sensing performance as a function of the LSPR spectral position. Firstly, we show the ambiguities that can arise from the description of the sensitivity in the wavelength and energy scales. However, we will see how such ambiguities can be circumvented with the introduction of the figure of merit (FOM), defined as the quotient between sensitivity and width of the resonance peaks, since this parameter is equivalent in both energy and wavelength scales. The spectral analysis reveals that the sensitivity to local changes of refractive index close to the metal surface can be comparable or even larger than that of conventional SPR sensors when the resonance position of the nanoparticles is properly selected. Indeed, for a fixed nanoparticle volume, we show that the surface sensitivity only depends on the spectral position of the resonance, whereas the shape of the particle only plays a secondary role. In addition, the FOM displays an optimized spectral region, located between 700 and 900 nm in the case of gold, which coincides with the region where the quotient between real and imaginary parts of the dielectric constant of the metal is maximized.

Finally, we study the influence of the supporting substrate and adhesion layers, required to improve the mechanical stability of the nanoparticles, on their refractometric FOMs. Just the presence of the substrate can induce a sensitivity reduction larger than 40%, especially in substrates with high refractive index. On the other hand, the adhesion layer can drastically downgrade the sensing performance of plasmonic nanoparticles due to the large decrease of their scattering or extinction cross-sections and the substantial broadening of their LSPR peaks. In the particular case of Cr adhesion layers, the FOM can show a fourfold decrease, while the scattering cross-section can be reduced close to one order of magnitude, adding drastic constraints to the limit of detection and performance of nanoplasmonic sensors. Therefore, minimization of the substrate refractive index and the thickness of the adhesion layers are prerequisites to ensure excellent limits of detection in refractometric nanoplasmonic sensors.

Keywords

Localize Surface Plasmon Resonance Adhesion Layer Resonance Wavelength Finite Different Time Domain Dielectric Coating 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

  1. 1.
    Anker JN, Hall WP, Lyandres O, et al. Biosensing with plasmonic nanosensors. Nat Mater. 2008;7(6):442–53.CrossRefGoogle Scholar
  2. 2.
    Sepulveda B, Angelome PC, Lechuga LM, et al. LSPR-based nanobiosensors. Nano Today. 2009;4(3):244–51.CrossRefGoogle Scholar
  3. 3.
    Lal S, Link S, Halas NJ. Nano-optics from sensing to waveguiding. Nat Photonics. 2007;1:641–8.CrossRefGoogle Scholar
  4. 4.
    Bohren CF, Huffman DR. Absorption and scattering by small particles. New York: Wiley-Interscience; 1983.Google Scholar
  5. 5.
    Miller MM, Lazarides AA. Sensitivity of metal nanoparticle surface plasmon resonance to the dielectric environment. J Phys Chem B. 2005;109(46):21556–65.CrossRefGoogle Scholar
  6. 6.
    Lee KS, El-Sayed MA. Gold and silver nanoparticles in sensing and imaging: sensitivity of plasmon response to size, shape, and metal composition. J Phys Chem B. 2006;110(39):19220–5.CrossRefGoogle Scholar
  7. 7.
    Chen HJ, Kou XS, Yang Z, et al. Shape- and size-dependent refractive index sensitivity of gold nanoparticles. Langmuir. 2008;24(10):5233–7.CrossRefGoogle Scholar
  8. 8.
    Larsson EM, Alegret J, Kall M, et al. Sensing characteristics of NIR localized surface plasmon resonances in gold nanorings for application as ultrasensitive biosensors. Nano Lett. 2007;7(5):1256–63.CrossRefGoogle Scholar
  9. 9.
    Wang H, Brandl DW, Le F, et al. Nanorice: a hybrid plasmonic nanostructure. Nano Lett. 2006;6(4):827–32.CrossRefGoogle Scholar
  10. 10.
    Otte MA, Sepulveda B, Ni WH, et al. Identification of the optimal spectral region for plasmonic and nanoplasmonic sensing. ACS Nano. 2010;4(1):349–57.CrossRefGoogle Scholar
  11. 11.
    Becker J, Trugler A, Jakab A, et al. The optimal aspect ratio of gold nanorods for plasmonic bio-sensing. Plasmonics. 2010;5(2):161–7.CrossRefGoogle Scholar
  12. 12.
    Homola J. Present and future of surface plasmon resonance biosensors. Anal Bioanal Chem. 2003;377(3):528–39.CrossRefGoogle Scholar
  13. 13.
    Svedendahl M, Chen S, Dmitriev A, et al. Refractometric sensing using propagating versus localized surface plasmons: a direct comparison. Nano Lett. 2009;9(12):4428–33.CrossRefGoogle Scholar
  14. 14.
    Schubert M. Polarization-dependent optical parameters of arbitrarily anisotropic homogeneous layered systems. Phys Rev B. 1996;53(8):4265–74.CrossRefGoogle Scholar
  15. 15.
    Knight MW, Wu YP, Lassiter JB, et al. Substrates matter: influence of an adjacent dielectric on an individual plasmonic nanoparticle. Nano Lett. 2009;9(5):2188–92.CrossRefGoogle Scholar
  16. 16.
    Vernon KC, Funston AM, Novo C, et al. Influence of particle-substrate interaction on localized plasmon resonances. Nano Lett. 2010;10(6):2080–6.CrossRefGoogle Scholar
  17. 17.
    Brian B, Sepulveda B, Alaverdyan Y, et al. Sensitivity enhancement of nanoplasmonic sensors in low refractive index substrates. Opt Express. 2009;17(3):2015–23.CrossRefGoogle Scholar
  18. 18.
    Gunnarsson L, Rindzevicius T, Prikulis J, et al. Confined plasmons in nanofabricated single silver particle pairs: experimental observations of strong interparticle interactions. J Phys Chem B. 2005;109(3):1079–87.CrossRefGoogle Scholar
  19. 19.
    Acimovic SS, Kreuzer MP, Gonzalez MU, et al. Plasmon near-field coupling in metal dimers as a step toward single-molecule sensing. ACS Nano. 2009;3(5):1231–7.CrossRefGoogle Scholar
  20. 20.
    Fredriksson H, Alaverdyan Y, Dmitriev A, et al. Hole-mask colloidal lithography. Adv Mater. 2007;19(23):4297.CrossRefGoogle Scholar
  21. 21.
    Dmitriev A, Hagglund C, Chen S, et al. Enhanced nanoplasmonic optical sensors with reduced substrate effect. Nano Lett. 2008;8(11):3893–8.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2012

Authors and Affiliations

  1. 1.NanoBiosensors and Bioanalytical Applications Group, Research Center on Nanoscience and Nanotechnology (CIN2: CSIC-ICN)BarcelonaSpain
  2. 2.CSIC-ICNBarcelonaSpain

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