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Optical label-free biosensors based on surface plasmon resonance

Research Area: Lab-on-a-chip label-free biosensors

Main Researcher: Peter Debackere

Surface Plasmons are peculiar electromagnetic modes that exist at the surface of metal layers, such as gold. Their high intensity at the surface of the metal explains their extreme sensitivity for chemical or biological interactions near the metal surface.

Conventionally, these surface modes are excited by shining light on a thin metal film. For certain combinations of wavelength and incidence angle the reflection of the light will go through a minimum because the incident light is resonantly absorbed as surface plasmons. The refractive index change caused by the adsorption of the biomolecules translates to a measurable variation of the resonance angle.

In this project we want to combine the SOI material system with a gold surface to obtain a fully integrated surface plasmon biosensor. A schematic of the proposed structure is shown in the figure below. The gold layer on top of the optical waveguide can support multiple surface plasmon modes which can be used to detect the refractive index in the vicinity of this layer. The device is based on the interference between two surface plasmon modes.

The surface will be chemically modified with detector molecules. When using gold, thiol- and/or disulphide-containing molecules can be chemisorbed onto the metal. In this project self assembling monolayers (SAMís) with functional end groups, e.g. amine or carboxylic acid, will be used to decorate the gold and to serve as anchoring sites for subsequent attachment of the selected detector molecule.

Schematic setup (left) and illustration of the interference effect(right)
Schematic setup (left) and illustration of the interference effect(right)

When scanning over a certain wavelength interval the transmission will show a pronounced minimum. The wavelength for which this minimum occurs is directly related to the refractive index in the vicinity of the gold layer, and is thus also related to the amount of detector molecule attached to the thiol groups. The figure below shows preliminary measurement results showing the interference of two surface plasmon modes.

Preliminary measurement results demonstrating proof-of-principle
Preliminary measurement results demonstrating proof-of-principle

Other people involved:

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Si based waveguide and surface plasmon sensors Si based waveguide and surface plasmon sensors

Publications

    International Journals

  1. P.P.P. Debackere, R. Baets, P. Bienstman, Bulk sensing experiments using a surface-plasmon interferometer, Optics Letters, 34(18), p.2858-2860 (2009)  Download this Publication (403KB).
  2. P.P.P. Debackere, S. Scheerlinck, P. Bienstman, R. Baets, Surface plasmon interferometer in silicon-on-insulator: novel concept for an integrated biosensor: Reply, Optics Express, 15(21), p.13651-13653 (2007)  Download this Publication (369KB).
  3. P.P.P. Debackere, P. Bienstman, R. Baets, Adaptive spatial resolution: application to surface plasmon waveguide modes, Optical and Quantum Electronics, 38(9-11), p.857-867 (2006)  Download this Publication (963KB).
  4. P.P.P. Debackere, S. Scheerlinck, P. Bienstman, R. Baets, Surface plasmon interferometer in silicon-on-insulator: novel concept for an integrated biosensor, Optics Express, 14(16), p.7063-7072 (2006)  Download this Publication (382KB).
      International Conferences

    1. G. Yurtsever, K. De Vos, T. Claes, P.P.P. Debackere, P. Bienstman, R. Baets, Photonic Biosensors in Silicon-on-Insulator , 2nd International Conference On Silicon Photonics (invited), United States, (2010)  Download this Publication (124KB).
    2. K. De Vos, P.P.P. Debackere, T. Claes, J. Girones, W.A.D. De Cort, E. Schacht, R. Baets, P. Bienstman, Label-free biosensors on silicon-on-insulator optical chips, SPIE Optics and Photonics (invited), 7397(37), United States, (2009)  Download this Publication (1.5MB).
    3. K. De Vos, P.P.P. Debackere, R. Baets, P. Bienstman, Label-free biosensors on Silicon-on-Insulator optical chips based on microring cavities and surface plasmon interferometry, ICTON 2008 (invited), 2, Greece, p.88-91 (2008)  Download this Publication (325KB).
    4. P.P.P. Debackere, K. De Vos, S. Scheerlinck, P. Bienstman, R. Baets, Silicon-on-Insulator as a Platform for Biosensors, Frontiers research Meeting, (2007)  Download this Publication (406KB).
    5. P.P.P. Debackere, D. Taillaert, S. Scheerlinck, K. De Vos, P. Bienstman, R. Baets, Si based waveguide and surface plasmon sensors, Photonics West 2007: Silicon Photonics II (invited), 6477, United States, p.647719 (2007)  Download this Publication (1.7MB).
    6. P.P.P. Debackere, S. Scheerlinck, P. Bienstman, R. Baets, A Biosensor based on Surface Plasmon Interference, LEOS Benelux Annual Symposium, Netherlands, (2006)  Download this Publication (1.4MB).
    7. P.P.P. Debackere, S. Scheerlinck, P. Bienstman, R. Baets, Surface Plasmon Interferometer in Silicon-on-Insulator: Novel Concept for an Integrated Biosensor, Group IV Photonics , Canada, p.7-10 (2006)  Download this Publication (909KB).
    8. P.P.P. Debackere, P. Bienstman, R. Baets, Improved ASR convergence for the simulation of Surface Plasmon Waveguide Modes, ICTON (COSTP 11 training school), p.We.P.15 (2006)  Download this Publication (419KB).
    9. P.P.P. Debackere, P. Bienstman, R. Baets, Improved ASR Convergence for the Simulation of Surface Plasmon Waveguide Modes, OWTNM 2006, Italy, p.14 (2006)  Download this Publication (60KB).

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