0000000001302945
AUTHOR
Nicolas Sok
showing 37 related works from this author
Direct subphthalocyanine conjugation to bombesin vs. indirect conjugation to its lipidic nanocarrier
2016
International audience; Bombesin (BBN) was covalently bound to graftable subphthalocyanine (SubPc) or to a cholesterol derivative, a component of a liposome that encapsulates non-graftable SubPc. The latter bioconjugation approach was suitable to address the stability of SubPc and was achieved by copper-free click-chemistry on the outer-face of the liposome. Liposomes were purified (FPLC) and then analyzed in size (outer diameter about 60 nm measured by DLS). In vitro binding studies allowed to determine the IC50 13.9 nM for one component of the liposome, cholesterol, conjugated to BBN. Hence, azido- (or alkynyl-) liposomes give fluorophores with no reactive functional group available on th…
Thermal Denaturation of Pea Globulins (Pisum sativum L.)—Molecular Interactions Leading to Heat-Induced Protein Aggregation
2013
The heat-induced denaturation and aggregation of mixed pea globulins (8%, w/w) were investigated using differential scanning calorimetry (DSC), SDS-PAGE, and size-exclusion chromatography (SEC-HPLC). DSC data showed that the pea proteins denaturation temperature (T(d)) was heating-rate dependent. The T(d) value decreased by about 4 °C by lowering the heating rate from 10 to 5 °C/min. The SDS-PAGE analysis revealed that protein denaturation upon heating at 90 °C was mainly governed by noncovalent interaction. The SEC-HPLC measurements indicated that low-denatured legumin (≈350-410 kDa) and vicilin/convicilin (≈170 kDa) globulins were heat-denatured and most of their subunits reassociated int…
Efficient Synthesis of Multifunctional Chelating Agents Based on Tetraazacycloalkanes
2018
An efficient route has been developed for the synthesis of multifunctional tetraazacycloalkanes (in particular 1,4,7,10-tetraazacyclotridecane) incorporating an aminomethyl pendant arm on the carbon skeleton. Starting from the appropriate C-functionalized bisaminal-protected intermediate, the target macrocycles were easily obtained by means of a step-by-step introduction of the desired functional groups onto the free primary amine group, followed by deprotection of the bisaminal intermediates. This straightforward and versatile synthetic approach paves the way for the design of a new family of multifunctional chelators.
Dry vs soaked wood: Modulating the volatile extractible fraction of oak wood by heat treatments
2012
The aim of this study was to analyze the impact of the water content of wood on the concentrations of volatile compounds which can be extracted after heat treatments. Head Space-Solid Phase Micro Extraction Gas Chromatography coupled to Mass Spectrometry (HS-SPME GC-MS) has been used to compare the concentrations of six aroma compounds (vanillin, furfural, eugenol, guaiacol and cis- and trans-whisky lactones) in hydroalcoholic extracts of heated oak wood samples either previously soaked in hot water or not. Except for eugenol, concentrations of extracted aromas appeared to be lower in soaked woods than in dry woods for temperatures up to 200 °C. If a delaying effect of water could explain s…
Iron intake among Lebanese women: sociodemographic factors, iron-rich dietary patterns, and preparation of hummus, a Mediterranean dish
2021
Background: Plant-based foods such as hummus are alternative to animal protein, and when properly pre-pared, they help to alleviate nutritional iron deficiency that leads to anemia, a global health problem. Objective: The objective was to assess iron intake among Lebanese women and related participant’s charac-teristics, discern iron-rich dietary patterns, evaluate their association with nutrients intake and participant’s sociodemographic characteristics, and identify the women preparing hummus traditionally and properly for an enhanced iron bioavailability. Design: A cross-sectional study of 400 Lebanese women (18–74 years old) was conducted in Lebanon. Data from a questionnaire, including…
A New pH-Dependent Macrocyclic Rhodamine B-Based Fluorescent Probe for Copper Detection in White Wine
2019
For efficiently measuring copper (II) ions in the acidic media of white wine, a new chemosensor based on rhodamine B coupled to a tetraazamacrocyclic ring (13aneN4CH2NH2) was designed and synthesized by a one-pot reaction using ethanol as a green solvent. The obtained chemosensor was characterized via NMR, UV and fluorescent spectra. It was marked with no color emission under neutral pH conditions, with a pink color emission under acidic conditions, and a magenta color emission under acidic conditions where copper (II) ions were present. The sensitivity towards copper (II) ions was tested and verified over Ca2+, Ag+, Zn2+, Mg2+, Co2+, Ni2+, Fe2+, Pb2+, Cd2+, Fe3+, and Mn2+, with a detection…
An Off-On-Off Fluorescent Sensor for pH Windows Based on the 13aneN4-Zn 2+ System
2016
International audience; The new ligand L was prepared and features a 13-membered tetraaza macrocyclic ring with a 1,8-naphthalimide fluorophore appended to a C atom of its backbone. The protonation constants of L as well as its complexation constants with Zn2+ ions were determined in 1:1 water/methanol solutions by potentiometric titrations. Fluorimetric pH titrations were performed with L alone and L in the presence of Zn2+ ions (1:1), and the species distributions (%) versus pH were compared. A window-shaped fluorescence trend was observed with pH for the L/Zn2+ system, which behaves as an off-on-off pH sensor. The on window is centred in the 6.5-7.5 pH range, in correspondence with the f…
Efficient synthesis of new C-functionalized macrocyclic polyamines
2010
A powerful synthetic route for the preparation of new poly-azamacrocycles, valuable precursors of bifunctional chelating agents with applications in nuclear medicine, is reported. The desired functional group was introduced onto the macro-cycle backbone during the cyclization step, thus avoiding the tedious preparation of a C-functionalized synthon. The regioselective reaction of macrocycles bearing an aminomethyl pendant arm with aldehydes is also described.
Micelles as containers for self-assembled nanodevices: a fluorescent sensor for lipophilicity
2008
Potentiometric titrations, fluorescence versus pH titrations, dynamic light scattering and fluorescence polarization anisotropy studies demonstrate that inside the nanodimensioned Triton X-100 micelles, 1-pyrenecarboxylic acid, PCOO-, forms an apical complex with the Zn2+ cation encircled by a lipophilic cyclen ligand and hugely increasing its fluorescence. The ability of the Zn2+-cyclen-PCOO- complex plus its micellar container to act as a fluorescent sensor to evaluate the lipophilicity of molecular species is demonstrated on the fatty acid series CH 3(CH2)xCOOH (x=0-16). At pH 7.4 a decrease in fluorescence is observed on the addition of fatty acids that is directly related to their chai…
A micellar multitasking device: sensing pH windows and gauging the lipophilicity of drugs with fluorescent signals.
2010
A multitasking fluorescent device can be obtained by forming micelles of Triton X-100, containing a lipophilic macrocyclic Cu(2+) complex and the coordinating fluorophore Coumarin 343 (C343), which features a COOH moiety. At low pH the two micellised components do not interact, and the fluorescence of Courmarin 343 (C343) is intense. At intermediate pH, C343 is deprotonated and coordinates to the Cu(2+) centre in its apical position, with fluorescence quenching. At higher pH the deprotonated C343 is displaced from Cu(2+) by the formation of an OH(-) complex, and the fluorescence is revived. This allows the system to carry out its first task as it behaves as an "on-off-on" fluorescent sensor…
Monitoring of transglutaminase crosslinking reaction by 1H NMR spectroscopy on model substrates
2015
International audience; A new method based on 1H NMR spectroscopy was developed for monitoring transglutaminase crosslinking reaction with model molecules (CBZ-Gln-Gly and N-α-acetyl-lysine). The transglutaminase reaction led to the appearance of new resonances on NMR spectrum as well as significant decrease in others. The new observed resonances, originated from newly formed ɛ-(γ-glutamyl)lysine isopeptide bonds, evidence the enzymatic reaction and allow to quantify the ɛ-(γ-glutamyl)lysine fragment. Moreover, the decrease in resonance intensity, originated from lysine, permit to determine the crosslinking degree. These results obtained by 1H NMR spectroscopy can be used as an alternative …
A monolayer of a Cu2+-tetraazamacrocyclic complex on glass as the adhesive layer for silver nanoparticles grafting, in the preparation of surface-act…
2011
International audience; A silane-derivatized tetraaza Cu2+ macrocyclic complex is prepared, which forms monolayers on glass surfaces, capable of allowing the further deposition of a stable monolayer of silver nanoparticles, obtaining by this, surfaces that display an enhanced antibacterial activity against Staphylococcus aureus and Escherichia coli.
Reinforced cyclam derivatives functionalized on the bridging unit
2016
International audience; A new synthetic method has been developed for the preparation of reinforced cyclams (1,4,8,11-tetraazacyclotetradecane) C-functionalized on the bridging unit, by using a "one pot" reaction starting from the appropriate bis-aminal cyclam intermediate. The high reactivity of quaternized aminal moiety toward nucleophilic agent has been used to elaborate a new class of cross-bridged and side-bridged cyclam derivatives containing cyanide group on the ethylene bridge. Several chelators and corresponding copper(II) complexes have been prepared and characterized by X-ray diffraction. These new constrained polyazamacrocycles are valuable precursors of bifunctional chelating a…
The Cu(II) complex of a C-lipophilized 13aneN4 macrocycle with an additional protonable amino group as micellar anion receptor.
2009
Three 13aneN4 macrocyclic ligands have been prepared bearing a -CH(2)NHR side arm (R = H, n-C(5)H(11), n-C(10)H(21)) on a carbon atom. When Cu(2+) is complexed in the macrocyclic ring, the amino group of the side arm undergoes an acid-base protonation equilibrium but it is not able to coordinate apically the metal cation even when it is deprotonated. The Cu(2+) complex with the ligand bearing the longest appended aliphatic chain is fully confined inside Triton X-100 micelles, and its ability to bind and sequestrate a series of anions inside micelles has been studied at two different pH values, i.e. both with protonated and neutral side-arm amino group. The favourable role played by the prot…
Lemon Juice, Sesame Paste, and Autoclaving Influence Iron Bioavailability of Hummus: Assessment by an In Vitro Digestion/Caco-2 Cell Model
2020
Hummus, an iron-containing plant-based dish mainly made from chickpea puré
Direct NMR evidence for the dissociation of sulfur-dioxide-bound acetaldehyde under acidic conditions: Impact on wines oxidative stability
2021
Abstract SO2 reaction with electrophilic species present in wine, including in particular carbonyl compounds, is responsible for the reduction of its protective effect during wine aging. In the present study, direct 1H NMR profiling used to monitor the reactivity of SO2 with acetaldehyde under wine-like oxidation conditions. The dissociation of acetaldehyde bound SO2 was evidenced suggesting that released free SO2 can further act as an antioxidant. EPR and DPPH assays showed an increasing antioxidant capacity of wine with the increase in the concentration of acetaldehyde sulfonate. The presence of acetaldehyde sulfonate in wines was correlated with the overall antioxidant activity of wines.…
Design of new sensitive α,β-unsaturated carbonyl 1,8-naphtalimide fluorescent probes for thiol bioimaging
2017
International audience; We report herein an efficient synthesis of news naphtalimide-based fluorescent derivatives functionalized with an a,(3-unsaturated carbonyl group. Probes were synthesized from reaction of an amino-naphtalimide precursor with maleic anhydride. Photophysical study of fluorescent probes and cells labelling were performed, and showed that the reactive derivatives exhibit rich turn on fluorescence properties in presence of different biological thiol (Glutathione and Cysteine) making these systems a very promising way for thiol bioimaging.
1H NMR Spectroscopy As Tool To Study Transglutaminase Crosslinking Of Pea Globulin
2013
Skiathos Island, GREECE - 30 May - 02 June 2013; International audience; A new method based on NMR spectroscopy was developed to detect the G-L (GlutamylLysine) isopeptide bonds formed by the enzymatic transglutaminase reaction. Because of thecomplexity of NMR signals of proteins due to their structures, the method was first developedon a model system (glutamine and lysine) to simplify the detection of the G-L residue. Andthen, the results were applied on the real protein matrix (pea globulin). MTG treatment ofmodel system led to the appearance of a new resonance on NMR spectrum which isoriginated probably from the ε-methylene protons of lysine residues covalently linked toglutamine. The co…
Préparation de liposomes fonctionnels pour l’encapsulation de composés bioactifs ou de sondes moléculaires fluorescentes pour l’imagerie cellulaire
2016
At ICMUB Institute, SUV liposomes have been used to achieve fluorophore encapsulation (subphtalocyanine) for cellular imaging [1] and have been bioconjugated to a peptide (bombesin) to achieve site-specificity, thanks to the structural modification of cholesterol, a component of the liposome, upon introduction of a reactive function. Hence, such liposomes fonctionnalised on the outer face may react with the terminal function of the peptide. Upon purification of the liposome by FPLC a 15 % encapsulation rate was measured by UV/Vis and attempted by ICP. The (outer) diameter of the liposomes (dDLS and dMET) ranged between 20 and 60 nm depending on the type of function or substituents on the ou…
CCDC 1439080: Experimental Crystal Structure Determination
2016
Related Article: Nicolas Sok, Isabelle Baglin, Yoann Rousselin, Frederic Boschetti, Claire Bernhard, Christine Goze, Franck Denat|2016|New J.Chem.|40|5829|doi:10.1039/C5NJ03488D
CCDC 1583210: Experimental Crystal Structure Determination
2018
Related Article: Nicolas Sok, Claire Bernhard, Pauline Désogère, Christine Goze, Yoann Rousselin, Frédéric Boschetti, Isabelle Baglin, Franck Denat|2018|Eur.J.Org.Chem.|2018|4762|doi:10.1002/ejoc.201800801
CCDC 1456530: Experimental Crystal Structure Determination
2016
Related Article: Yann Bernhard, Elodie Gigot, Victor Goncalves, Mathieu Moreau, Nicolas Sok, Philippe Richard, Richard A. Decréau|2016|Org.Biomol.Chem.|14|4511|doi:10.1039/C6OB00530F
CCDC 1439078: Experimental Crystal Structure Determination
2016
Related Article: Nicolas Sok, Isabelle Baglin, Yoann Rousselin, Frederic Boschetti, Claire Bernhard, Christine Goze, Franck Denat|2016|New J.Chem.|40|5829|doi:10.1039/C5NJ03488D
CCDC 1439081: Experimental Crystal Structure Determination
2016
Related Article: Nicolas Sok, Isabelle Baglin, Yoann Rousselin, Frederic Boschetti, Claire Bernhard, Christine Goze, Franck Denat|2016|New J.Chem.|40|5829|doi:10.1039/C5NJ03488D
CCDC 1439077: Experimental Crystal Structure Determination
2016
Related Article: Nicolas Sok, Isabelle Baglin, Yoann Rousselin, Frederic Boschetti, Claire Bernhard, Christine Goze, Franck Denat|2016|New J.Chem.|40|5829|doi:10.1039/C5NJ03488D
CCDC 1583212: Experimental Crystal Structure Determination
2018
Related Article: Nicolas Sok, Claire Bernhard, Pauline Désogère, Christine Goze, Yoann Rousselin, Frédéric Boschetti, Isabelle Baglin, Franck Denat|2018|Eur.J.Org.Chem.|2018|4762|doi:10.1002/ejoc.201800801
CCDC 1583211: Experimental Crystal Structure Determination
2018
Related Article: Nicolas Sok, Claire Bernhard, Pauline Désogère, Christine Goze, Yoann Rousselin, Frédéric Boschetti, Isabelle Baglin, Franck Denat|2018|Eur.J.Org.Chem.|2018|4762|doi:10.1002/ejoc.201800801
CCDC 1583209: Experimental Crystal Structure Determination
2018
Related Article: Nicolas Sok, Claire Bernhard, Pauline Désogère, Christine Goze, Yoann Rousselin, Frédéric Boschetti, Isabelle Baglin, Franck Denat|2018|Eur.J.Org.Chem.|2018|4762|doi:10.1002/ejoc.201800801
CCDC 1439082: Experimental Crystal Structure Determination
2016
Related Article: Nicolas Sok, Isabelle Baglin, Yoann Rousselin, Frederic Boschetti, Claire Bernhard, Christine Goze, Franck Denat|2016|New J.Chem.|40|5829|doi:10.1039/C5NJ03488D
CCDC 1476682: Experimental Crystal Structure Determination
2017
Related Article: Nicolas Sok, Isabelle Baglin, Christelle Basset, Fatima Fakkor, Evelyne Kohli, Yoann Rousselin, Claire Bernhard, Frédéric Boschetti, Christine Goze, Franck Denat|2017|RSC Advances|7|28291|doi:10.1039/C7RA04218C
CCDC 1583208: Experimental Crystal Structure Determination
2018
Related Article: Nicolas Sok, Claire Bernhard, Pauline Désogère, Christine Goze, Yoann Rousselin, Frédéric Boschetti, Isabelle Baglin, Franck Denat|2018|Eur.J.Org.Chem.|2018|4762|doi:10.1002/ejoc.201800801
CCDC 1439079: Experimental Crystal Structure Determination
2016
Related Article: Nicolas Sok, Isabelle Baglin, Yoann Rousselin, Frederic Boschetti, Claire Bernhard, Christine Goze, Franck Denat|2016|New J.Chem.|40|5829|doi:10.1039/C5NJ03488D
CCDC 1476683: Experimental Crystal Structure Determination
2017
Related Article: Nicolas Sok, Isabelle Baglin, Christelle Basset, Fatima Fakkor, Evelyne Kohli, Yoann Rousselin, Claire Bernhard, Frédéric Boschetti, Christine Goze, Franck Denat|2017|RSC Advances|7|28291|doi:10.1039/C7RA04218C
CCDC 1476681: Experimental Crystal Structure Determination
2017
Related Article: Nicolas Sok, Isabelle Baglin, Christelle Basset, Fatima Fakkor, Evelyne Kohli, Yoann Rousselin, Claire Bernhard, Frédéric Boschetti, Christine Goze, Franck Denat|2017|RSC Advances|7|28291|doi:10.1039/C7RA04218C
CCDC 1054357: Experimental Crystal Structure Determination
2016
Related Article: Nicolas Sok, Maria Nikolantonaki, Stephane Guyot, Thanh Dat Nguyen, Anne-Sophie Viaux, Franck Bagala, Yoann Rousselin, Florence Husson, Régis Gougeon, Rémi Saurel|2017|Sens.Actuators,B|242|865|doi:10.1016/j.snb.2016.09.171
CCDC 1583213: Experimental Crystal Structure Determination
2018
Related Article: Nicolas Sok, Claire Bernhard, Pauline Désogère, Christine Goze, Yoann Rousselin, Frédéric Boschetti, Isabelle Baglin, Franck Denat|2018|Eur.J.Org.Chem.|2018|4762|doi:10.1002/ejoc.201800801
CCDC 1054356: Experimental Crystal Structure Determination
2016
Related Article: Nicolas Sok, Maria Nikolantonaki, Stephane Guyot, Thanh Dat Nguyen, Anne-Sophie Viaux, Franck Bagala, Yoann Rousselin, Florence Husson, Régis Gougeon, Rémi Saurel|2017|Sens.Actuators,B|242|865|doi:10.1016/j.snb.2016.09.171