References of "Dreesen, Laurent"
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See detailDevelopment of an all-solid-state pulsed picosecond laser system for nonlinear spectroscopy
Mani, A. A.; Jazmati, A. K.; Zidan, M. D. et al

in Physical Chemical News (2007), 36

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See detailSum-frequency generation spectroscopy of DNA monolayers
Sartenaer, Yannick; Tourillon, Gérard; Dreesen, Laurent ULg et al

in Biosensors & Bioelectronics (2007), 22

The anchoring of thiolated single-strandedDNA(HS-ssDNA) monolayers onto platinum substrates was investigated by sum-frequency generation spectroscopy. Different buffer solutions were used for the ... [more ▼]

The anchoring of thiolated single-strandedDNA(HS-ssDNA) monolayers onto platinum substrates was investigated by sum-frequency generation spectroscopy. Different buffer solutions were used for the preparation of the adlayers. Vibrational fingerprints in the 2700–3100 cm−1 spectral range showed the intercalation of Tris/EDTA (TE) buffer molecules within the HS-ssDNA self-assembled monolayer. Buffer contribution to SFG can be quenched either by using SFG inactive molecules like KH2PO4/K2HPO4/NaCl (PBS) or by repeated rinsing of the DNA layer with pure water. Comparing the SFG spectra of HS-ssDNA and mercaptohexanol (MCH), which had been self-assembled onto the same substrate, enabled us to infer ordering of the anchor arms and strong disordering of the DNA strands of HS-ssDNA monolayers self-assembled on platinum. [less ▲]

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See detailThe interaction between a protein and a ligand molecule studied by linear and non-linear optical spectroscopies
Dreesen, Laurent ULg; Méthivier, C.; Sartenaer, Y. et al

in Physical Chemical News (2007), 36

We use infrared reflection-adsorption (IRRAS) and sum-frequency generation (SFG) spectroscopies to study the interaction between a protein (avidin) and a ligand molecule (biocytin or its thiol derivative ... [more ▼]

We use infrared reflection-adsorption (IRRAS) and sum-frequency generation (SFG) spectroscopies to study the interaction between a protein (avidin) and a ligand molecule (biocytin or its thiol derivative) adsorbed on metals (Au and Ag) and insulators (CaF2 in two separate spectral ranges 2800-3500 cm-1 and 1400-1800 cm-1, respectively. No specific interaction is detected by SFG when the measurements are carried out on metals although IRRAS measurements attest the presence of a protein ad-layer. This is explained by the disordered character of the adsorbed film of avidin which is therefore SFG inactive. When the experiments are performed on an insulating substrate, no change of the biocytin/CaF2 SFG spectrum is detected in the low spectral range (1400-1800 cm-1) after immersion in an avidin solution in contrast with what was clearly demonstrated in the 2800-3500 cm-1 spectral range. Finally, we report, for the first time, the observation by SFG of the CH2 scissor vibration mode at 1465 cm-1. [less ▲]

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See detailTotal internal reflection sum-frequency generation spectroscopy and dense gold nanoparticles monolayer: a route for probing adsorbed molecules
Tourillon, Gérard; Dreesen, Laurent ULg; Volcke, Cédric et al

in Nanotechnology (2007), 18

We show that sum-frequency generation spectroscopy performed in the total internal reflection configuration (TIR–SFG) combined with a dense gold nanoparticles monolayer allows us to study, with an ... [more ▼]

We show that sum-frequency generation spectroscopy performed in the total internal reflection configuration (TIR–SFG) combined with a dense gold nanoparticles monolayer allows us to study, with an excellent signal to noise ratio and high signal to background ratio, the conformation of adsorbed molecules. Dodecanethiol (DDT) was used as probe molecules in order to assess the potentialities of the approach. An enhancement of more than one order of magnitude of the SFG signals arising from the adsorbed species is observed with the TIR geometry compared to the external reflection one while the SFG non-resonant contribution remains the same for both configurations. Although further work is required to fully understand the origin of the SFG process on nanoparticles, our work opens new possibilities for studying nanostructures. [less ▲]

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See detailAdsorption Properties of the Penicillin Derivative DTPA on Gold Substrates
Dreesen, Laurent ULg; Silien, Christophe; Volcke, Cédric et al

in Chemphyschem : A European Journal of Chemical Physics and Physical Chemistry (2007), 8(7), 1071-1076

Despite the large number of articles and patents dealing with penicillin and other b-lactam antibiotics, there have been no reports about the self-assembly of such substances as monolayers on gold ... [more ▼]

Despite the large number of articles and patents dealing with penicillin and other b-lactam antibiotics, there have been no reports about the self-assembly of such substances as monolayers on gold surfaces. The main reason stems from the high reactivity of the b-lactam ring, which hinders the development of molecules possessing this entity together with a metal-anchoring function. Herein, we present the synthesis of a novel molecule, 6-[(R,S)-5-(1,2-dithiolan-3-yl)pentanoyl-amino]-penicillanic acid, which combines the b-lactam ring and a metal-anchoring group. Using spectroscopic tools, we demonstrate the chemisorption of this compound on gold as self-assembled monolayers without any alteration of the penicillin pharmacophore and document its reactivity towards a penicillin-binding protein, BlaR-CTD. Our work is a preliminary step towards the development of new biosensors and well-ordered protein arrays, both based on the high affinity of penicillin for penicillin-binding proteins. [less ▲]

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See detailHigh energy and short pulses generation by Nd:yttrium aluminum garnet laser mode-locked using frequency-doubling nonlinear mirror
Mani, A. A.; Lis, D.; Grawet, L. et al

in Optics Communications (2007), 276

The generation of laser pulses with energies of >40 mJ at 25 Hz and durations variable from 15 ps to 45 ps using an Nd:yttrium aluminum garnet laser mode-locked with a Stankov nonlinear mirror is ... [more ▼]

The generation of laser pulses with energies of >40 mJ at 25 Hz and durations variable from 15 ps to 45 ps using an Nd:yttrium aluminum garnet laser mode-locked with a Stankov nonlinear mirror is demonstrated. This laser is used to pump an optical parametric generator-amplifier, which is tunable in the visible spectral range. [less ▲]

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See detailSynthesis and characterization of aromatic self-assembled monolayers containing methylene and ethyleneglycol entities by means of sum-frequency generation spectroscopy
Dreesen, Laurent ULg; Sartenaer, Y.; Peremans, A. et al

in Thin Solid Films (2006), 500

We use infrared-visible sum-frequency generation (SFG) spectroscopy in order to investigate the adsorption properties on Pt(111) of molecules having CH3–C6H4–(O–CH2–CH2)n –O–(CH2)m –SH as general chemical ... [more ▼]

We use infrared-visible sum-frequency generation (SFG) spectroscopy in order to investigate the adsorption properties on Pt(111) of molecules having CH3–C6H4–(O–CH2–CH2)n –O–(CH2)m –SH as general chemical formula. We synthesized three molecules defined by the values m=5 n =4, m =11 n =4, m=11 n =8 and characterized them by Nuclear Magnetic Resonance spectroscopy. Thanks to spectroscopic measurements, we show that these molecules build self-assembled monolayers on Pt(111). First, the weak SFG signals arising from the ad-layer indicate low order and surface coverage of the substrate by these molecules. Next, the vibrational fingerprints of the aforementioned molecules are determined between 2825 and 3125 cm 1 and the observed SFG spectral features are ascribed on the basis of the analysis of shorter and simpler molecules (1- dodecanethiol, 4-methylbenzenethiol and CH3–C6H4–O–(CH2)11–SH) also adsorbed on Pt(111). The occurrence of methylene vibration modes indicates a significant amount of chain defects whatever the n and m numbers are. Finally, the identification of a particular vibration mode, characteristic of the aromatic ring, enables us to qualitatively discuss the effect of the number of methylene and ethylene glycol entities on its orientation. More precisely, higher these numbers, more tilted (with respect to the substrate normal) the aromatic ring plane is. [less ▲]

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See detailComparative study of decyl thiocyanate and decanethiol self-assembled monolayers on gold substrates
Dreesen, Laurent ULg; Volcke, C.; Sartenaer, Y. et al

in Surface Science (2006), 600

In a recent paper Ciszek et al. [J.W. Ciszek, M.P. Stewart, J.M. Tour, J. Am. Chem. Soc. 126 2004) 13172] showed that organic thiocyanates may be an interesting alternative to the use of thiols for ... [more ▼]

In a recent paper Ciszek et al. [J.W. Ciszek, M.P. Stewart, J.M. Tour, J. Am. Chem. Soc. 126 2004) 13172] showed that organic thiocyanates may be an interesting alternative to the use of thiols for thiolate assemblies. We use scanning tunnelling microscopy (STM), infrared reflection absorption and sum-frequency generation spectroscopies (IRRAS and SFG) in order to study the adsorption properties of decyl thiocyanates (DTCN) and compare them to the decanethiol (DT) ones. Firstly, IRRAS measurements show that DTCN molecules form self-assembled monolayers (SAMs) on gold via a thiolate link with the metallic substrate. Secondly, the DTCN SAM on gold is less ordered than the DT one as highlighted by SFG spectroscopy. Indeed, the intensities of the methyl vibration modes vanish while the methylene ones increase when DTCN molecules are adsorbed on the substrate instead of DT. We explain the differences in SAMs quality on the basis of STM measurements which reveal differences in molecular order and packing. [less ▲]

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See detailMolecular conformation and electronic properties of protoporphyrin-IX self-assembled monolayers adsorbed on a Pt(111) surface
Humbert, C.; Volcke, C.; Sartenaer, Y. et al

in Surface Science (2006), 600

Monolayers of protoporphyrin-IX molecules are prepared on a Pt(111) surface by a self-assembly process in order to manufacture organic devices with controlled electronic properties. Scanning tunnelling ... [more ▼]

Monolayers of protoporphyrin-IX molecules are prepared on a Pt(111) surface by a self-assembly process in order to manufacture organic devices with controlled electronic properties. Scanning tunnelling microscopy (STM) and two-colour sum-frequency generation (2C-SFG) are performed ex situ in ambient air, in order to characterize their molecular conformation and electronic properties at the monolayer level, respectively. STM measurements performed with functionalized gold tips reveal a high covering rate of the metal surface. 2C-SFG measurements highlight CH stretching modes of vinyl substituted groups (R-CH=CH2) in the 2800–3200 cm-1 infrared spectral range and particular electronic features in the visible spectral range, i.e. a Soret band red shift and band separation compared to the liquid phase. Moreover, similar measurements are performed on Zn(II)Protoporphyrin-IX and 5-[p-(6-mercaptohexoxy)-phenyl]-10,15,20-triphenylporphin films for comparison. These results suggest a film conformation with the molecules having different tilt angles with respect to the substrate normal, depending on the ion metal presence or the chain length bonded to the porphyrin moiety. [less ▲]

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See detailOn the Protoporphyrin Monolayers Conformation
Humbert, Christophe; Dreesen, Laurent ULg; Sartenaer, Yannick et al

in Chemphyschem : A European Journal of Chemical Physics and Physical Chemistry (2006), 7

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See detailThiocyanate and thiol self-assembling process on platinum investigated by means of sum-frequency generation
Sartenaer, Yannick; Tourillon, Gérard; Louette, Pierre et al

Poster (2005, September)

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See detailComparative study of decyl thiocyanate and decanethiol self-assembled monolayers on gold substrates
Dreesen, Laurent ULg; Volcke, Cédric; Sartenaer, Yannick et al

Poster (2005, September)

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See detailMolecular conformation and electronic properties of protoporphyrin-IX self-assembled monolayers adsorbed on Pt(111) surface
Humbert, Christophe; Volcke, Cédric; Sartenaer, Yannick et al

Poster (2005, September)

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See detailSum-frequency generation from surface species in porous silicon
Mattei, Giorgio; Valentini, Veronica; Yakovlev, Vladimir et al

in Phys. Stat. Sol. (a) (2005), 202(8), 1487-1491

For the first time, the sum-frequency generation (SFG) spectra of surface species have been measured in porous silicon (PS) layers. The range of the vibrations 2000–2300 cm–1 for the native species Si–Hx ... [more ▼]

For the first time, the sum-frequency generation (SFG) spectra of surface species have been measured in porous silicon (PS) layers. The range of the vibrations 2000–2300 cm–1 for the native species Si–Hx has been explored. Furthermore for the studied mesoporous materials, it has been found that, as opposed to the infrared absorption, the SFG signal increases with porosity. Finally, the angular dependence and the enhancement of the SFG signal were measured in a one-dimensional PS photonic crystal structure with a defect producing an energy level in the photonic band gap. [less ▲]

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See detailSum-frequency generation spectrocopy applied to model biosensors systems
Dreesen, Laurent ULg; Sartenaer, Yannick; Humbert, Christophe et al

Conference (2004, November)

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See detailTwo-color-sum-frequency generation characterization of a protein monolayer adsorbed on a metallic substrate
Dreesen, Laurent ULg; Sartenaer, Yannick; Humbert, Christophe et al

Poster (2004, June)

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See detailTwo-color-sum-frequency generation characterization of a protein monolayer adsorbed on a metallic substrate
Dreesen, Laurent ULg; Sartenaer, Yannick; Humbert, Christophe et al

Poster (2004, May 25)

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See detailPicosecond laser for performance of efficient nonlinear spectroscopy from 10 to 21 mm
Mani, A. A.; Schultz, Z. D.; Gewirth, A. A. et al

in Optics Letters (2004), 29(3), 274-276

Laser tunability from 10 to 21 mm is obtained by use of an optical parametric oscillator based on a KTP crystal followed by a difference-frequency stage with a CdSe crystal. An all-solid-state picosecond ... [more ▼]

Laser tunability from 10 to 21 mm is obtained by use of an optical parametric oscillator based on a KTP crystal followed by a difference-frequency stage with a CdSe crystal. An all-solid-state picosecond Nd:YAG oscillator mode locked by a frequency-doubling nonlinear mirror is used for synchronous pumping. [less ▲]

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See detailMethanol dissociative adsorption on Pt(1 0 0) as studied by nonlinear vibrational spectroscopy
Vidal, Franck; Busson, B.; Six, C. et al

in Journal of Electroanalytical Chemistry (2004), 563

The methanol dissociative adsorption on Pt(1 0 0) at low potentials in the hydrogen region is studied using nonlinear vibrational sum-frequency generation (SFG) spectroscopy. It is shown that adsorbed ... [more ▼]

The methanol dissociative adsorption on Pt(1 0 0) at low potentials in the hydrogen region is studied using nonlinear vibrational sum-frequency generation (SFG) spectroscopy. It is shown that adsorbed hydrogen atoms effectively block atop sites at the surface. In the hydrogen potential region, CO produced by the methanol dissociation adsorbs at step-edges and in bridge sites on terraces as shown by the characteristic stretching frequencies observed for adsorbed CO. [less ▲]

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