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Molecular Organization and Interactions at surface

by Rosso Michel - published on , updated on

We realize functional hybrid structures associating an inorganic material, silicon, with (bio)molecular species or an organometallic film. A multistep protocol is generally necessary : (1) organic grafting of a dense functionalized monolayer on oxide free silicon; (2) covalent coupling of molecular entities by peptide bonding or "click chemistry". We often use well-defined H-terminated Si(111) surfaces to combine spectroscopic characterizations (FTIR, XPS) with scanning probe imaging (AFM/STM) for a quantitative determination of the surface composition. In some devices, a carbonated amorphous PECVD thin film is employed.

Current projects :

 Silicon biosensors for the monitoring of biomolecular interactions
We develop silicon biosensors based on the covalent anchoring of probes allowing for specific and selective recognition of targets. We used FTIR-ATR spectroscopy to quantify the composition of the molecular layers and to optimize the biomolecular interactions. We are currently working on the specific interactions between glycan probes and lectins targets [1] and DNA aptamers probes against the mycotoxin Ochratoxin A.
[1] “Quantitative assessment of the multivalent protein-carbohydrate interactions on silicon”, J. Yang, J.-N. Chazalviel, A. Siriwardena, R. Boukherroub, F. Ozanam, S. Szunerits, and A. C. Gouget-Laemmel, Analytical Chemistry, 86 (2014) 10340-10349.

 Photoswitching surfaces :
Photoswitchning surfaces are of interest in different fields. We investigate the photoswitching properties of organic photochromic compounds immobilized on silicon surfaces… Read more

 Conditioning and functionalization of silicon nitride
Silicon nitride thin-film is a common material in the microelectronic or glass industry thanks to its dielectric and mechanical properties. We investigate the surface chemistry of its oxyde free layer by tuning the silicon-nitrogen ratio and/or by H2 plasma treatment [1]. Various strategy of functionalization are envisaged.

[1] “Etching and Chemical Control of the Silicon Nitride Surface”, M. Brunet, D. Aureau, P. Chantraine, F. Guillemot, A. Etcheberry, A. C. Gouget-Laemmel and F. Ozanam, ACS Appl. Mater. Interfaces, 9 (2017), 3075-3084.

Recent works:
Composition of organic monolayers by calibrated FTIR
Alkyl monolayers hydrosilylation on H-Si(111) surfaces
Covalent immobilization of molecular entities on functionalized silicon surfaces
Acid / base titration acide in two dimensions
Selective oxidation of alkyl monolayers in soft plasma
Thermal desorption of organic monolayers grafted on silicon
Electrochemical grafting on silicon