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Plasmonic biochips based on amorphous silicon carbon alloy

by Rosso Michel - published on , updated on

Participants : J.-N. Chazalviel, A.C. Gouget-Laemmel, A. Moraillon, F. Ozanam

PhD students : C. Andrei , J. Yang (2014), L. Touahir (2010)

Collaboration : S. Szunerits et R. Boukherroub (Institut de Recherche Interdisciplinaire, Villeneuve d’Asq)

The use of noble metal nanoparticles is well-adapted for the conception of biosensors due to their unique optical properties. They exhibit a strong UV-Vis absorption band, known as the localized surface plasmon resonance. This band LSPR is sensitive to the local refractive index changes that occur during the molecular recognition between probes and targets.

We used thin films of hydrogenated silicon carbon alloys a-Si1-x(CH3)x:H deposited by PECVD on metallic nanostructures (gold and silver) immobilized on glass to develop LSPR biosensors (Figure A). These thin films act as dielectric spacers allowing for the control of the optical properties of the nanoparticles and of the surface chemistry thanks to the covalent attachment of DNA probes on carboxy-terminated monolayers via Si-C. The DNA hybridization was studied by UV-Visible and a detection limit in the low nM was found. By coupling the fluorescence with the localized surface plasmons, the sensitivity of the detection was enhanced (by a factor of 35 compared to commercial slides) with a limit of detection lower than 5 fM (Figure B). We also proposed a multiplex imaging tool allowing for in-situ analysis of the biological recognition by fluorescence, LSPR and Raman (two patents in 2009 and 2010, innovation prize of Ecole Polytechnique in 2011). We are currently working on the development of glycans biochips for the study of glycan/protein interactions. The plasmonic effects are also exploited to develop a direct method of target detection (with labelling) by SERS imaging (Surface-enhanced Raman Spectroscopy).

Publications :

"Localized surface plasmon-enhanced fluorescence spectroscopy for highly-sensitive real-time detection of DNA hybridization", L. Touahir, E. Galopin, R. Boukherroub, A. C. Gouget-Laemmel, J.-N. Chazalviel, F. Ozanam* and S. Szunerits, Biosensors and Bioelectronics 25 (2010) 2579–2585.

“Surface plasmon-enhanced fluorescence spectroscopy on silver based SPR substrates”, L. Touahir, A. Jenkins, R. Boukherroub, A. C. Gouget-Laemmel, J.-N. Chazalviel, J. Peretti, F. Ozanam and S. Szunerits, Journal of Physical Chemistry C 114 (2010) 22582-22589.

“Carbohydrate microarray for the detection of glycan-protein interactions using metal-enhanced fluorescence”, J. Yang, A. Moraillon, A. Siriwardena, R. Boukherroub, F. Ozanam, A. C. Gouget-Laemmel, S. Szunerits, Analytical Chemistry 87 (2015) 3721-3728.