References of "Jérôme, Christine"
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See detailImprégnation de polymères par voie CO2 supercritique: suivi in situ par microscopie FTIR
Champeau, Mathilde; Thomassin, Jean-Michel ULg; Jérôme, Christine ULg et al

Conference (2012, September 15)

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See detailEffects of cellular morphology on electricalconductivity of carbon nanotubes containing nanocomposites foams
Tran, Minh Phuong ULg; Detrembleur, Christophe ULg; Thomassin, Jean-Michel ULg et al

Conference (2012, September 13)

In the last few years, polymer carbon nanotubes (CNTs) nanocomposites foams have received increasing attention due to their potential applications in electrostatic dissipation (ESD) and in electromagnetic ... [more ▼]

In the last few years, polymer carbon nanotubes (CNTs) nanocomposites foams have received increasing attention due to their potential applications in electrostatic dissipation (ESD) and in electromagnetic interferences (EMI) shielding. To be efficient, these foams must exhibit appropriate electrical conductivity (> 1 S/m) and dielectric constant. A good understanding of the influence of the foam structural parameters on the electrical properties of the foam will ultimately enable the optimum design of these materials for the targeted applications. A wide range of poly(methyl methacrylate) (PMMA)/CNTs nanocomposites foams were synthesized using the supercritical CO2 technology. Different foaming parameters, such as the temperature, impregnation pressure, time and rate of depressurization were varied to modify the foam structure. The amount of carbon nanotubes in PMMA plays the most important role in increasing the electrical conductivity. Nanocomposite foams show higher electrical conductivity than non-foamed nanocomposites at the same volume content of CNTs. Effects of foam morphology such as cell-density; pore size, volume expansion, and cell-wall thickness on electrical conductivity were comprehensively assessed. High electrical conductivity can be achieved with nanocomposite foams that have high volume expansion, small pore size, high cell density, and thin cell-walls [less ▲]

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See detailStimuli-responsive Magnetic Nanohybrids for Triggered Drug Release and Potential Tumor Treatment via Hyperthermia
Liu, Ji ULg; Detrembleur, Christophe ULg; Mornet, Stéphane et al

Poster (2012, September 13)

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See detailMechanistic investigation and selectivity of the grafting onto C60 of macroradicals prepared by cobalt-mediated radical polymerization
Hurtgen, Marie ULg; Debuigne, Antoine ULg; Gigmes, Didier et al

in Polymer (2012), 53(20), 4353-4358

The grafting mechanism of poly(vinyl acetate) macroradicals prepared by cobalt-mediated radical polymerization onto C60 is investigated. The experimental conditions directly impact the nature and ... [more ▼]

The grafting mechanism of poly(vinyl acetate) macroradicals prepared by cobalt-mediated radical polymerization onto C60 is investigated. The experimental conditions directly impact the nature and stability of the PVAc/C60 adducts. In the presence of residual initiating radicals that can compete with PVAc! macroradicals for addition onto C60, mixtures of PVAc/C60 adducts having between one and eight polymer chains per C60 are formed. PVAc/C60 adducts prepared with low [PVAc]:[C60] ratios may contain weak C60-C60 bonds that further dissociate and account for the instability of the products. The formation of such dimers can be lessened by increasing the temperature from 30 !C to 100 !C. The temperature increase also allows a complete dissociation of the PVAc-Co dormant species into PVAc! macroradicals and an almost quantitative grafting of eight PVAc chains onto C60, leading to well-de!ned C60(PVAc)8 octa-adducts. These results might shed new light on the grafting onto C60 of macroradicals prepared by other CRP techniques. [less ▲]

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See detailThermally induced coupling of poly(thiophene)-based block copolymers prepared by Grignard metathesis polymerization: a straightforward route toward highly regioregular multiblock conjugated copolymers
Ouhib, Farid ULg; Desbief, Simon; Lazzaroni, Roberto et al

in Macromolecules (2012), 45(17), 6796-6806

We report on a convenient and simple process to prepare highly regioregular poly(thiophene)-based multiblock copolymers by a novel thermally induced coupling reaction. Diblock copolymers of 3 ... [more ▼]

We report on a convenient and simple process to prepare highly regioregular poly(thiophene)-based multiblock copolymers by a novel thermally induced coupling reaction. Diblock copolymers of 3-hexylthiophene (3HT) and 2,5-dibromo-3-(2-(2-tetrahydropyranyl-2-oxy)ethyl)thiophene (THPET) end-capped by a nickel complex (Br-P3HT-b-PTHPET-Ni(dppp)Br) are first prepared using Ni(dppp)Cl2 as catalyst at 30 °C by Grignard metathesis polymerization (GRIM process). The coupling of these α-bromo, ω-Ni(dppp)Br telechelic diblock copolymers then occurs by heating the solution of the copolymer at 80 °C for a few hours without adding any additional reagent. Reactions are complete in only 10 min when heating the copolymer at 120 °C using microwaves. The deprotection of the alcohol groups of PTHPET blocks allows further modifications such as the incorporation of acrylates by esterification. AFM analysis on thin films shows the influence of the nature of side chains (protected alcohol or acrylate), the molecular weight, and the architecture (diblock or multiblock) of the copolymer on the supramolecular organization of the polythiophene chains. [less ▲]

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See detailUse of new surface active carbohydrate esters for the synthesis of polyhipes in supercritical CO2
Boyère, Cédric ULg; Favrelle, Audrey; Grignard, Bruno ULg et al

Poster (2012, September 10)

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See detailα-Acetal, ω-alkyne poly(ethylene oxide) as a versatile building block for the synthesis of glycoconjugated graft-copolymers suited for targeted drug delivery
Freichels, Hélène; Alaimo, David ULg; Auzély-Velty, Rachel et al

in Bioconjugate Chemistry (2012), 23(9), 1740-1752

α-Acetal, ω-alkyne poly(ethylene oxide) was synthesized as building block of glycoconjugated poly(ε-caprolactone)-graft-poly(ethylene oxide) (PCL-g-PEO) copolymers. The alkyne group is indeed instrumental ... [more ▼]

α-Acetal, ω-alkyne poly(ethylene oxide) was synthesized as building block of glycoconjugated poly(ε-caprolactone)-graft-poly(ethylene oxide) (PCL-g-PEO) copolymers. The alkyne group is indeed instrumental for the PEGylation of a poly(α-azido-ε-caprolactone-co-ε-caprolactone) copolymer by the Huisgen’s 1,3 dipolar cycloaddition, i.e., a click reaction. Moreover, deprotection of the acetal end-group of the hydrophilic PEO grafts followed by reductive amination of the accordingly formed aldehyde with an aminated sugar is a valuable strategy of glycoconjugation of the graft copolymer, whose micelles are then potential. A model molecule (fluoresceinamine) was first considered in order to optimize the experimental conditions for the reductive amination. These conditions were then extended to the decoration of the graft copolymer micelles with mannose, which is a targeting agent of dendritic cells and macrophages. The bioavailability of the sugar units at the surface of micelles was investigated by surface plasmon resonance (SPR). The same question was addressed to nanoparticles stabilized by the graft copolymer. Enzyme linked lectin assay (ELLA) confirmed the availability of mannose at the nanoparticle surface. [less ▲]

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See detailOrganometallic-mediated radical polymerization of vinyl amides: Effect of metal coordination
Kermagoret, Anthony ULg; Morin, A.; Hurtgen, Marie ULg et al

Poster (2012, September 04)

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See detailOrganometallic-mediated radical polymerization of vinyl amides: Effect of metal coordination
Kermagoret, Anthony ULg; Morin, A.; Hurtgen, Marie ULg et al

Conference (2012, September 04)

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See detailFunctional degradable polymers for advanced drug delivery systems
Cajot, Sébastien; Riva, Raphaël ULg; Jérôme, Christine ULg

Conference (2012, September)

Nowadays, polymer micelles have attracted an increasing interest in pharmaceutical research because they could be used as efficient drug delivery systems. Micelles of amphiphilic block copolymers are ... [more ▼]

Nowadays, polymer micelles have attracted an increasing interest in pharmaceutical research because they could be used as efficient drug delivery systems. Micelles of amphiphilic block copolymers are supramolecular core-shell type assemblies of several tens of nanometers in diameter. In principle, the micelle core is usually constructed with biodegradable hydrophobic polymers such as aliphatic polyesters, e.g. poly(ε-caprolactone) (PCL), which serves as a reservoir for the incorporation of various lipophilic drugs. Water soluble poly(ethylene oxide) (PEO) is most frequently used to build the micelle corona because it is very efficient in preventing protein adsorption at surfaces and in stabilizing micelles in the blood compartment, making particles invisible to the body defense system. Even if micelles get a high stability in aqueous media thanks to their low critical micellar concentration, micelle dissociation is not always preserved when they are injected in the blood compartment. A way to provide the micelle stability during their administration is to cross-link them. Different kinds of cross-linked micelles can be investigated depending on the localization of the cross-linking. Shell cross-linked micelles or nanocage structures with a degradable core have the great advantage to reach drug encapsulation with a high loading rate. However, cross-linking the hydrophilic shell may affect the stealthiness of the carrier. Thus, we have designed reversibly cross-linked micelles by introducing the cross-linking bridges in the hydrophobic segment of the block copolymer, rather than in the hydrophilic one, leading so to more internal cross-linking and thus preserving the mobility of the hydrophilic segment. Three different localizations of the cross-linking has been targeted; (i) loose core cross-linking of a core-corona system, (ii) tight core cross-linking of a core-shell-corona system (the shell and the core being both hydrophobic and the corona hydrophilic) and (iii) tight shell cross-linking of a similar core-shell-corona system. To reach this goal, three types of amphiphilic copolymers have been used bearing pendent azide groups in the hydrophobic segment. These copolymers have been obtained by starting the ring-opening polymerization of ε-CL and a functional CL, either as a mixture or sequentially from a poly(ethylene oxide) macroinitiator leading to the three targeted architectures. The azide groups located along the PCL backbone have then been used to cross-link the micelles by the Huisgens cycloaddition with a bis-alkyne cross-linker. The choice of this cross-linker has also taken into account the requirement to make the cross-linking reversible. For that purpose, disulfide bridges have been selected in order to impart reversibility to the cross-linking by intracellular reduction. Indeed, the marked concentration difference of glutathione between extra- and intra-cellular environments has already been used to trigger drug release by intracellular disulfide bond cleavage. Accordingly, a bis-alkyne disulfide molecule has been chosen as cross-linker. The micellization and cross-linking of these amphiphilic azido macromolecules have been studied. The reversibility of the cross-linking in reductive environment and the cross-linked micelles stealthiness have been tested. [less ▲]

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See detailBioactive Intraocular Lens - A New Concept to Control Secondary Cataract
Huang, Yi-Shiang ULg; Alexandre, Michaël ULg; Bozukova, Dimitriya et al

Poster (2012, August 29)

A cataract is pathology opacity of the lens, causing impairment of vision or even blindness. Today, a surgery is still the only available treatment. The intraocular lens (IOL) is a polymer implant ... [more ▼]

A cataract is pathology opacity of the lens, causing impairment of vision or even blindness. Today, a surgery is still the only available treatment. The intraocular lens (IOL) is a polymer implant designed to replace the natural lens in the cataract surgery. The materials for IOL require excellent optical properties for light transmission, mechanical properties for folding injection during surgery, and biological properties for preventing body rejection. The biocompatibility - or more specified, bio-inert - seems to be the prerequisite in selecting the materials. [1] However, the bioinert materials could not satisfy the unmet need in the secondary cataract control. Posterior capsular opacification (PCO, or Secondary Cataract), characterized by a thick and cloudy layer of lens epithelial cells (LECs), is the most common postoperative complication. In 1997, a “Sandwich Theory” model was proposed to elucidate the developmental process of PCO. [2] In this model, the residual LECs between the lens capsular bag and the IOL undergo proliferation, migration, as well as transdifferentiation and finally induce PCO if the affinity to the IOL material is low. In our research, a bioactive molecule is introduced to the conventional acrylic hydrophilic polymer pHEMA(Poly(2-hydroxyethyl methacrylate)) by covalent conjugation. The RGD peptide sequence, being well-known for its tissue integration ability, is designed to stimulate the biointegration between the LECs and the IOL. [3]. Our data have shown the peptide grafted biomaterial not only exhibits similar optical and mechanical properties, but also reveals enhanced biological properties in cell adhesion and cell morphology maintenance. By means of surface functionalization of IOL to stabilize and restore LECs, the secondary cataract could be controlled in a regenerative medicine way. References [1] Dimitriya Bozukova (2010) Materials Science and Engineering R, 69: 63-83. [2] Reijo Linnola (1997) J Cataract Refract Surg., 10: 1539–42. [3] Ruoslahti E (1986) Cell, 44(4): 517-8. [less ▲]

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See detailSynthesis of microsphere-loaded porous polymers by combining emulsion and dispersion polymerisations in supercritical carbon dioxide
Boyère, Cédric ULg; Léonard, Alexandre ULg; Grignard, Bruno ULg et al

in Chemical Communications (2012), 48(67), 8356-8358

Highly porous materials were produced by acrylamide polymerisation templated by supercritical CO2-in-water emulsions using new fluorinated glycosurfactants. Properties of the resulting polymer scaffolds ... [more ▼]

Highly porous materials were produced by acrylamide polymerisation templated by supercritical CO2-in-water emulsions using new fluorinated glycosurfactants. Properties of the resulting polymer scaffolds were tuned by performing dispersion polymerisations within their cavities filled with supercritical CO2. [less ▲]

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See detailOnline monitoring of heterogeneous polymerizations in supercritical carbon dioxide by Raman spectroscopy
Grignard, Bruno ULg; Gilbert, Bernard ULg; Malherbe, Cédric ULg et al

in Chemphyschem : A European Journal of Chemical Physics and Physical Chemistry (2012), 13(11), 2666-2670

A novel setup is described to monitor the kinetics of homogeneous and heterogeneous reactions online using Raman spectroscopy under high pressure. The arrangement is based on a high-pressure reactor ... [more ▼]

A novel setup is described to monitor the kinetics of homogeneous and heterogeneous reactions online using Raman spectroscopy under high pressure. The arrangement is based on a high-pressure reactor equipped with a sapphire window in combination with a mobile probe that allows the collection of the back-scattered Raman signal at 360°. [less ▲]

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See detailClickable PEG conjugate obtained by ‘‘clip’’ photochemistry: Synthesis and
Pourcelle, Vincent; Le Duff, Cécile S.; Freichels, Hélène et al

in Journal of Fluorine Chemistry (2012), 140

In this paper, we describe a grafting methodology associated to a quantitative 19F NMR method (qNMR) for the conjugation of small molecules on a PEG building block aimed at click chemistry applications in ... [more ▼]

In this paper, we describe a grafting methodology associated to a quantitative 19F NMR method (qNMR) for the conjugation of small molecules on a PEG building block aimed at click chemistry applications in the domain of drug delivery systems. Acetylenic PEG (PEG-yne) was first derivatized with a fluorinated benzyl amine (TagF6) by means of photografting of a trifluoromethylphenyl diazirine bifunctional linker (TPD-clip). The amount of TagF6 grafted on PEG-yne was calculated by NMR using an internal standard (trifluoroethanol) and adjusting of the acquisition and processing parameters. NMR is used as a valuable alternative to the complex procedures often employed for the quantification of functionalities on biomaterials. The accuracy of the qNMR methodology was attested by controlling its linearity, the determination of limits of quantification and the percentage of recovery. A good assessment of the TagF6 grafting rates was obtained after taking into account the inherent unspecific adsorption that occurs on materials. This versatile methodology that combines simple chemistry and a common analytical tool was, in a second time, applied to the preparation of a PEG conjugated with a RGD (Arg-Gly-Asp) peptidomimetic in a controlled manner. [less ▲]

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See detailA green and bio-inspired process to afford durable anti-biofilm properties to stainless steel
Faure, Emilie; Vreuls, Christelle; Falentin-Daudré, Céline et al

in Biofouling (2012), 28(7), 719-728

A bio-inspired durable anti-biofilm coating was developed for industrial stainless steel (SS) surfaces. Two polymers inspired from the adhesive and cross-linking properties of mussels were designed and ... [more ▼]

A bio-inspired durable anti-biofilm coating was developed for industrial stainless steel (SS) surfaces. Two polymers inspired from the adhesive and cross-linking properties of mussels were designed and assembled from aqueous solutions onto SS surfaces to afford durable coatings. Trypsin, a commercially available broad spectrum serine protease, was grafted as the final active layer of the coating. Its proteolytic activity after long immersion periods was demonstrated against several substrata, viz. a synthetic molecule, N-a-benzoyl-DL-arginine-p-nitroanilide hydrochloride (BAPNA), a protein, FTC-casein, and Gram-positive biofilm forming bacterium Staphylococcus epidermidis. [less ▲]

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