References of "Jérôme, Christine"
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See detailCombination of lipase catalysis and thiol-Michael addition for the synthesis of carbohydrate esters used as stabilizers in supercritical carbon dioxide emulsions
Boyère, Cédric ULg; Favrelle, Audrey; Broze, Guy ULg et al

Poster (2011, November 21)

The use of aqueous dispersed media, such as emulsions and miniemulsions, has many advantages over solution processes for chemical transformations and polymerization reactions, i.e. limited environmental ... [more ▼]

The use of aqueous dispersed media, such as emulsions and miniemulsions, has many advantages over solution processes for chemical transformations and polymerization reactions, i.e. limited environmental impact, ease of products recovery and increased reaction rate. Although, dispersed media are usually implemented from water/solvent mixtures, supercritical carbon dioxide (scCO2) (Pc =74 bars; Tc = 31°C) constitutes an interesting alternative to the traditional organic solvents because it is inexpensive, non-toxic, non-flammable and environmentally friendlier. In this context, we develop a novel class of surface active compounds able to stabilize water/scCO2 emulsions, i.e. fluorinated modified carbohydrates. The hydrophilic head of the surfactant consists in a sugar moiety whereas the fluorinated tail has a strong affinity for the scCO2 phase. These carbohydrate esters are prepared by a two-step strategy which takes advantage of the selectivity of enzymatic catalysis and the versatility of the thiol-Michael addition reaction. The new thiolated mannose intermediate is a useful building block for the incorporation of unprotected sugar moieties into complex molecules. The surface active properties of the fluorinated derivatives have been evaluated as well as their use as stabilizers for the preparation of microparticles and highly porous polymer materials in scCO2. [less ▲]

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See detailSmart block copolymers for biomedical applications
Sibret, Pierre ULg; De Pauw, Marie-Claire ULg; Jérôme, Christine ULg

Poster (2011, November 21)

Smart polymers are polymers that respond with rapid changes to external stimuli such as pH, temperature, light or ionic strength. Responses to the stimuli may manifest themselves as changes in solubility ... [more ▼]

Smart polymers are polymers that respond with rapid changes to external stimuli such as pH, temperature, light or ionic strength. Responses to the stimuli may manifest themselves as changes in solubility, shape or surface characteristics. These materials are very intersesting for different biomedical applications such as drug delivery systems, tissue engineering or sensors. In this work, we focused on two separate systems: on the one hand, micelles and, on the other hand, iron oxide nanoparticles. These nanoparticles are generally synthesized in a one-step process by alkaline coprecipitation of iron (II) and iron (III) precursors. However, iron oxide nanoparticles are not stable enough in physiological conditions to be used as is. A stabiliser coating is needed to avoid aggregation and precipitation of the colloids in body fluids. For this coating, the polymer blocks chosen are PEO (to confer stealthiness), PAA (pH-responsive) and PNIPAM (thermoresponsive). This triblock copolymer was synthesized by RAFT polymerization and was used alone to form micelles and with iron oxide to make magnetic stabilized nanoparticles. The behaviour of micelles and coated nanoparticles was investigated by a combination of DLS, TEM and zeta potential measurements. To highlight the potentiality of these nanomaterials, their cytotoxicity will be studied and compared. [less ▲]

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See detailMorphology and mechanical properties of bisphenol A polycarbonate/poly(styrene-co-acrylonitrile) blends based clay nanocomposites
Lin, Demiao; Boschetti-de-Fierro, Adriana; Alexandre, Michaël ULg et al

in Composites Science & Technology (2011), 71(16), 1893-1897

Two organic modified clays (Cloisite®30B (CL30B) and PCL/Cloisite®30B masterbatch (MB30B)) were used to improve the mechanical properties of polycarbonate (PC)/poly (styrene-co-acrylonitrile) (SAN) blends ... [more ▼]

Two organic modified clays (Cloisite®30B (CL30B) and PCL/Cloisite®30B masterbatch (MB30B)) were used to improve the mechanical properties of polycarbonate (PC)/poly (styrene-co-acrylonitrile) (SAN) blends. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) measurements of the melt blended nanocomposites revealed that partially exfoliated and partially degraded structure was obtained and the clay platelets were located mostly in the SAN phase and at the two-phase boundary. Dispersion of the clay platelets is better when MB30B were used. The mechanical properties of the clays filled nanocomposites vary accordingly and when MB30B is used better mechanical properties can be achieved. Tensile strength increases 41% at maximum as the CL30B loading is 5 wt.%, while elongation at break decreases dramatically. Impact strength can be improved up to 430% compared to the pure blend when 1 wt.% MB30B was used. [less ▲]

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See detailNew functional poly(N-vinylpyrrolidone) based (co)polymers via photoinitiated cobalt-mediated radical polymerization
Debuigne, Antoine ULg; Schoumacher, Matthieu; Willet, Nicolas ULg et al

in Chemical Communications (2011), 47(47), 12703-12705

The photoinitiated cobalt-mediated radical polymerization enables the synthesis of novel alpha-functional and alpha,omega-telechelic polymers. In combination with ring-opening polymerization, it also ... [more ▼]

The photoinitiated cobalt-mediated radical polymerization enables the synthesis of novel alpha-functional and alpha,omega-telechelic polymers. In combination with ring-opening polymerization, it also produces new amphiphilic copolymers which self-assemble into flower-like vesicles in water. [less ▲]

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See detailPreparation and characterization of thermo-responsive gold nanohybrids
Liu, Ji ULg; Hurtgen, Marie ULg; Detrembleur, Christophe ULg et al

Poster (2011, October 25)

Stimuli-responsive nano-materials have been playing increasingly important roles in the biomedical field due to their ability to alter the physico-chemical properties in response to external stimuli, such ... [more ▼]

Stimuli-responsive nano-materials have been playing increasingly important roles in the biomedical field due to their ability to alter the physico-chemical properties in response to external stimuli, such as temperature, pH, ionic strength, magnetic field, etc. Nanohybrids bearing an inorganic core and thermo-responsive polymer shell are particularly applicable in target delivery and controlled drug release. Poly (N-vinylcaprolactam) (PNVCL) and its copolymers, exhibiting lower critical solution temperature (LCST) where the transition between hydrophilic and hydrophobic state happens, is one of the optimal choices for this core/shell structure. Here we present the in-situ fabrication of thermo-responsive gold nanohybrids coated with a novel poly(vinyl alcohol)-b-poly(N-vinylcaprolactam) (PVOH-b-PNVCL) block copolymer prepared by the cobalt-mediated radical polymerization (CMRP). The interaction between both PVOH and PNVCL segments and gold nanoparticles was confirmed by FT-IR spectra. A sharp thermo-induced phase transition with a good reversibility upon change in temperature was detected by DLS and UV/vis spectrometer. Furthermore, the presence of hydrophilic PVOH moieties endows the gold nanohybrids with improved colloidal stability above LCST without any flocculation detected, compared with the gold nanoparticles stabilized with PNVCL homopolymer. This kind of gold nanohybrids can be envisaged as a new drug delivery vehicle. [less ▲]

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See detailLipase catalysis and thiol-Michael addition: a relevant association for the synthesis of new surface active carbohydrate esters
Boyère, Cédric ULg; Favrelle, Audrey ULg; Broze, Guy ULg et al

in Carbohydrate Research (2011), 346(14), 2121-2125

A novel class of surface-active carbohydrate esters is prepared by a two-step strategy that takes advantage of the selectivity of enzymatic catalysis and the versatility of the thiol-Michael addition ... [more ▼]

A novel class of surface-active carbohydrate esters is prepared by a two-step strategy that takes advantage of the selectivity of enzymatic catalysis and the versatility of the thiol-Michael addition reaction. The surfactant performance of the produced aliphatic, fluorinated and silicon based sugar esters are evaluated by surface tension measurements. The novel thiolated mannose, made available in this work, appears as a powerful building block for the incorporation of unprotected sugar moieties into complex molecules. [less ▲]

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See detailSmart networks for biomedical applications
Jérôme, Christine ULg

Conference (2011, October 04)

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See detailStealth properties of poly(ethylene oxide)-based triblock copolymer micelles: A prerequisite for a pH-triggered targeting system
Van Butsele, Kathy; Morille, M.; Passirani, Catherine et al

in Acta Biomaterialia (2011), 7(10), 3700-3707

Evaluation of the biocompatibility of pH-triggered targeting micelles was performed with the goal of studying the effect of a poly(ethylene oxide) (PEO) coating on micelle stealth properties. Upon ... [more ▼]

Evaluation of the biocompatibility of pH-triggered targeting micelles was performed with the goal of studying the effect of a poly(ethylene oxide) (PEO) coating on micelle stealth properties. Upon protonation under acidic conditions, pH-sensitive poly(2-vinylpyridine) (P2VP) blocks were stretched, exhibiting positive charges at the periphery of the micelles as well as being a model targeting unit. The polymer micelles were based on two different macromolecular architectures, an ABC miktoarm star terpolymer and an ABC linear triblock copolymer, which combined three different polymer blocks, i.e. hydrophobic poly(E-caprolactone), PEO and P2VP. Neutral polymer micelles were formed at physiological pH. These systems were tested for their ability to avoid macrophage uptake, their complement activation and their pharmacological behavior after systemic injection in mice, as a function of their conformation (neutral or protonated). After protonation, complement activation and macrophage uptake were up to twofold higher than for neutral systems. By contrast, when P2VP blocks and the targeting unit were buried by the PEO shell at physiological pH, micelle stealth properties were improved, allowing their future systemic injection with an expected long circulation in blood. Smart systems responsive to pH were thus developed which therefore hold great promise for targeted drug delivery to an acidic tumoral environment. [less ▲]

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See detailStealth macromolecular platforms for the design of MRI blood pool contrast agents
Grogna, Mathurin ULg; Cloots, Rudi ULg; Luxen, André ULg et al

in Polymer Chemistry (2011), 2(10), 2316-2327

Stealth macromolecular platforms bearing alkyne groups and poly(ethylene oxide) brushes were synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization. The anchoring of Gd3 ... [more ▼]

Stealth macromolecular platforms bearing alkyne groups and poly(ethylene oxide) brushes were synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization. The anchoring of Gd3+-chelates bearing an azide group was then carried out by the Huisgen 1,3-dipolar cycloaddition (“click”) reaction in mild conditions, leading to macrocontrast agents for MRI applications. The gadolinium complex is hidden in the PEO shell that renders the macrocontrast agents free of any cytotoxicity and stealth to proteins of the immune system. Relaxometry measurements have evidenced an improved relaxivity of the macrocontrast agent compared to ungrafted gadolinium chelate. Moreover, this relaxivity is further enhanced when the spacer length between the Gd3+-chelate and the polymer backbone is shorter, as the result of its decreased tumbling rate. These novel products are therefore promising candidates for MRI applications. [less ▲]

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See detailOrganic compositions for repeatedly adjustable optical elements and such elements
Jérôme, Christine ULg; Alexandre, Michaël ULg; Jellali, Rachid ULg

Patent (2011)

The invention relates to an organic transparent liquid composition comprising preformed polymeric chains having some photoactive groups per chain that can reversibly couple, being capable in this way to ... [more ▼]

The invention relates to an organic transparent liquid composition comprising preformed polymeric chains having some photoactive groups per chain that can reversibly couple, being capable in this way to form a transparent solid polymer network with a shape that can be repeatedly and reversibly adjusted by at least local irradiation of the network with electromagnetic waves of different wave lengths whereby the liquid composition is cross-linked at at least one wave length L1 on the one hand and is liquid again by cleaving the cross-link nodes by irradiating the material at at least one other wavelength L2 on the other hand in order to repeatedly adjust the optical properties of said composition in its photo-cross linked state. The composition is applicable as a starting material for intraocular lenses and for other lenses and optical elements. [less ▲]

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See detailDisulfide bridges, new prospect in drug delivery systems?
Cajot, Sébastien ULg; Danhier, F.; Schol, Daureen ULg et al

Poster (2011, September 03)

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See detailGlucose-responsive layer-by-layer microcapsules as self-regulated insulin delivery system
Alaimo, David ULg; Detrembleur, Christophe ULg; Auzély-Velty, Rachel et al

Poster (2011, September 03)

Detailed reference viewed: 22 (3 ULg)
See detailSmart block copolymers for biomedical applications
Sibret, Pierre ULg; Schol, D; De Pauw, Marie-Claire ULg et al

Poster (2011, September 03)

Stimuli-responsive polymers are polymers that respond with rapid changes to external stimuli such as pH, temperature, light or ionic strength. Responses to the stimuli may manifest themselves as changes ... [more ▼]

Stimuli-responsive polymers are polymers that respond with rapid changes to external stimuli such as pH, temperature, light or ionic strength. Responses to the stimuli may manifest themselves as changes in solubility, shape or surface characteristics. They can also lead to the fomation of micelles or a sol-gel transition. These materials are very intersesting for different biomedical applications such as drug delivery systems, tissue engineering or sensors. In this work, we focused on two separate systems: on the one hand, micelles and, on the other hand, iron oxide nanoparticles. These nanoparticles are generally synthesized in a one-step process by alkaline coprecipitation of iron (II) and iron (III) precursors in aqueous solutions (Massart process). However, iron oxide nanoparticle suspensions produced by Massart process are not stable enough in physiological conditions to be used as is. A stabiliser coating is needed to avoid aggregation and consequent precipitation of the colloids in body fluids. For this coating, the polymer blocks chosen are: the poly(ethylene oxide) (PEO), the poly(acrylic acid) (PAA) and the poly(N-isopropyl acrylamide) (PNIPAM). The high flexibility and hydrophilicity of PEO chains make it an outstanding candidate for confering stealthiness to micelles and nanoparticles in order to avoid their rapid removal from the body by the opsonization process. The PAA is the pH-responsive block and the anchoring block. The PNIPAM is the thermoresponsive block with a thermal transition close to 37°C (99°F). Triblock copolymer was synthesized by a Reversible Addition Fragmentation Transfer Polymerization (RAFT) process combining poly(acrylic acid) PAA, poly(N-isopropylacrylamide) and poly(ethylene oxide) or poly[acrylate methoxy poly(ethylene oxide)]. This triblock copolymer was used alone to form micelles and with iron oxide to make magnetic stabilized nanoparticles. The behaviour of micelles and coated nanoparticles was investigated in different conditions by a combination of dynamic light scattering (DLS), transmission electron microscopy (TEM) and zeta potential measurements. Moreover, PAA-b-PNIPAM-b-PAMPEO nanofibers were obtained using electrospinning technique. These nanofibers present interesting prospects in the field of biomaterials and biomedical applications as they mimic the extracellular matrix of the skin. [less ▲]

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See detailStainless steel with robust anibacterial activiy based on a versatile and bio-inspired strategy
Faure, Emilie ULg; Lecomte, Philippe ULg; Vreuls, Christelle ULg et al

Conference (2011, September 01)

The synthesis of a poly(methacrylamide) bearing 3,4-dihydroxyphenylalanine inspired from the chemical composition of mussel adhesives will be presented. This homopolymer is designed to insure a multilayer ... [more ▼]

The synthesis of a poly(methacrylamide) bearing 3,4-dihydroxyphenylalanine inspired from the chemical composition of mussel adhesives will be presented. This homopolymer is designed to insure a multilayer film growth by covalent coupling during the layer-by-layer building with a homopolymer containing amino groups. The film cross-linking is initiated by adequately controlling both the redox state of the polymer and the pH of the solutions. This cross-linking is evidenced by solid-state 13C NMR with the occurrence of a typical signal of imine, traducing the Schiff base formation during film growth. The same coupling reaction is implemented for grafting an antibacterial peptide, Nisin, on a stainless steel substrate. Antibacterial activity against Bacillus subtilis is preserved even after long immersion time, as the result of the peptide covalent anchoring on the surface. All the processing steps, including the synthesis of the polymers and the peptide grafting, are performed in aqueous solutions under mild conditions. [less ▲]

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See detailConvenient grafting through approach for the preparation of stealth polymeric blood pool magnetic resonance imaging contrast agents
Grogna, Mathurin ULg; Cloots, Rudi ULg; Luxen, André ULg et al

in Journal of Polymer Science. Part A, Polymer Chemistry (2011), 49(17), 3700-3708

New hydrosoluble magnetic resonance imaging (MRI) macrocontrast agents are synthesized by reversible addition fragmentation chain transfer (RAFT) copolymerization of poly(ethylene oxide) methyl ether ... [more ▼]

New hydrosoluble magnetic resonance imaging (MRI) macrocontrast agents are synthesized by reversible addition fragmentation chain transfer (RAFT) copolymerization of poly(ethylene oxide) methyl ether acrylate (PEOMA) with an acrylamide bearing a ligand for gadolinium, followed by the complexation of Gd3+. This convenient and simple grafting through approach leads to macrocontrast agents with a high relaxivity at high frequency that is imparted by the restricted tumbling of the Gd3+ complex caused by its attachment to the polymer backbone. Importantly a very low protein adsorption is also evidenced by the hemolytic CH50 test. It is the result of the poly(ethylene oxide) (PEO) brush that efficiently hides the gadolinium complex and renders it stealth to the proteins of the immune system. Improved contrast and long blood circulating properties are thus expected for these macrocontrast agents. [less ▲]

Detailed reference viewed: 37 (13 ULg)
See detailPMMA/ carbon nanotube nanocomposite foams for EMI shielding application
Thomassin, Jean-Michel ULg; Vuluga, Daniela; Huynen, Isabelle et al

Conference (2011, August 30)

Detailed reference viewed: 27 (5 ULg)