References of "Jérôme, Christine"
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See detailDrug loading of polymer implants by supercritical CO2 assisted impregnation: a review
Champeau, Mathilde; Thomassin, Jean-Michel ULg; Tassaing, Thierry et al

in Journal of Controlled Release (2015), 209

Drug loaded implants also called drug-eluting implants have proven their benefits over simple implants. Among the developed manufacturing processes, the supercritical CO2 (scCO2) assisted impregnation has ... [more ▼]

Drug loaded implants also called drug-eluting implants have proven their benefits over simple implants. Among the developed manufacturing processes, the supercritical CO2 (scCO2) assisted impregnation has attracted growing attention to load Active Pharmaceutical Ingredients into polymer implants since it enables to recover a final implant free of any solvent residue and to operate under mild temperature which is suitable for processing with thermosensitive drugs. This paper is a review of the state-of-the-art and the application of the scCO2 assisted impregnation process to prepare drug-eluting implants. It introduces the process and presents its advantages for biomedical applications. The influences of the characteristics of the implied binary systems and of the experimental conditions on the drug loading are described. Then, the various current applications of this process for manufacturing drug-eluting implants are reviewed. Finally, the new emerging variations of this process are described. [less ▲]

Detailed reference viewed: 41 (10 ULg)
See detailCO2-sourced non-isocyanate polyurethanes: from the monomer synthesis to the elaboration of polymeric materials
Gennen, Sandro ULg; Grignard, Bruno ULg; Gilbert, Bernard ULg et al

Conference (2015, July 07)

Due to problems related to the rarefaction of fossil resources and the global warming that comes from CO2 emissions, new carbon feedstocks that are abundant, renewable, non-toxic, inexpensive and ... [more ▼]

Due to problems related to the rarefaction of fossil resources and the global warming that comes from CO2 emissions, new carbon feedstocks that are abundant, renewable, non-toxic, inexpensive and environmentally friendly must be explored to produce chemicals. Besides the valorization of bio-based raw materials, the use of CO2 as a C1 carbon source into added-value products has gained interest in both academic and industrial fields. One promising way to valorize CO2 relies on its chemical fixation onto epoxides to produce cyclic carbonates that find applications as electrolytes in lithium ion batteries, as aprotic polar solvents or as useful intermediates for polycarbonates. Cyclic carbonates also react with primary amines to produce 2-hydroxyethylurethane. This reaction can be extrapolated to the synthesis of non-isocyanate polyurethanes (NIPU) by polyaddition of bifunctional cyclic carbonates with diamines.5 This study focusses on (i) the synthesis of cyclic carbonates using new highly efficient organocatalysts and (ii) their valorization as monomers to produce non-isocyanate polyurethanes. First, we have identified a bicomponent organocatalyst for the very fast synthesis of cyclic carbonates from CO2 and epoxides under very mild reaction conditions. Kinetics of reactions were followed by online Raman spectroscopy. NMR titrations were realized to evidence the mechanism of activation of this novel organocatalytic system that will be discussed in detail this talk. The second objective relies on the development of new efficient organocatalysts for the synthesis of high molar masses NIPUs in short reaction times. Organic compounds interacting with the cyclic carbonate by hydrogen bonding were identified and their catalytic activity was highlighted by a model reaction between ethylene carbonate and a primary amine before extrapolation to the synthesis of NIPUs that find applications as coatings or foamed materials. [less ▲]

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See detailEfficient hydrogen-bond donor activators for the synthesis of bio-based cyclic carbonates from CO2 and vegetable oils: a combined in-situ FT-IR and DFT study
Alves, Margot ULg; Méreau, Raphaël; Grignard, Bruno ULg et al

Conference (2015, July 06)

The present research aims at developing new very efficient organocatalysts for the chemical fixation of carbon dioxide onto epoxides that are precursors of non-isocyanate polyurethanes (NIPUs). Although ... [more ▼]

The present research aims at developing new very efficient organocatalysts for the chemical fixation of carbon dioxide onto epoxides that are precursors of non-isocyanate polyurethanes (NIPUs). Although this area of research is the subject of many works, the catalytic performance must be further enhanced in particular for the carbonatation of vegetable-based precursors while respecting environmental standards. In this context, we developed a new organocatalytic platform based on the combination of ammonium salts with single or double hydrogen bond donor activators that showed unexpected catalytic activity for the fast addition of CO2 onto epoxidized oils under mild conditions. First of all, in situ kinetic studies of the cycloaddition of CO2 onto model epoxidized oils were monitored by FT-IR spectroscopy in order to evaluate the influence of the hydrogen bond structure and various parameters such as the pressure, the temperature, the catalyst loading, and the nature of the epoxide on the reaction kinetics. Thanks to this catalyst screening, we found that ammonium salt/fluorinated hydrogen bond donors bicomponent organocatalysts were by far more efficient than that proposed in the literature under mild conditions (60°C, 2MPa). Then, the reaction mechanism of the organocatalyzed cycloaddition of propylene oxide onto CO2 was elucidated by performing Density Functional Theory (DFT). Our theoretical results highlighted the key role of the hydrogen bond interaction between the epoxide and the activators for the enhancement of the catalytic platform’s efficiency. [less ▲]

Detailed reference viewed: 92 (6 ULg)
See detailPhoto- and thermo-reversible crosslinked recyclable shape memory materials
Defize, Thomas ULg; Riva, Raphaël ULg; Thomassin, Jean-Michel ULg et al

Poster (2015, July 02)

Shape memory polymers (SMPs) are remarkable materials able to switch from a stressed deformed state (temporary shape) to their initial relaxed state (permanent shape) by the application of a stimulus ... [more ▼]

Shape memory polymers (SMPs) are remarkable materials able to switch from a stressed deformed state (temporary shape) to their initial relaxed state (permanent shape) by the application of a stimulus; such as heat or light. Typically; the shape memory property is generally observed for chemically or physically cross-linked polymers that exhibit an elastomeric behavior above a phase transition; e.g. glass or melting transition. As an example; cross-linked semi-crystalline poly(ε-caprolactone) (PCL) is widely studied for the development of SMPs. As most of SMPs are irreversibly cross-linked material; their reprocessing is impossible preventing any recycling. Thereby; reversible reactions; allowing the formation/cleavage of the network; raise tremendous interest for the development of new SMPs. Recently, we reported the preparation reversibly cross-linked PCL-based SMP using the Diels-Alder (DA) reaction between furan and maleimide end-groups of 4-arm star-shaped PCL, well-known to create reversible bonds. After implementation, this shape memory material was demonstrated to be recyclable, and was characterized by excellent fixity and recovery before and after recycling experiments. However, the relatively low retro DA temperature of the furan-maleimide adducts led to an inelastic deformation during shape memory tensile cycles. In order to get rid of this drawback, an alternative approach was investigated. The substitution of the DA reaction by a photo-reversible reaction, typically the photo-induced (2+2) cycloaddition of coumarins, was proposed to prepare cross-linked PCL matrix presenting one-way and two-way memory properties, since photolabile adducts are supposed to be stable during shape memory tensile cycles. [less ▲]

Detailed reference viewed: 90 (8 ULg)
See detailDouble hydrophilic polyphosphoester containing copolymers as efficient templating agnets for calcium carbonate microparticles
Ergül, Zeynep ULg; Debuigne, Antoine ULg; Calvignac, Brice et al

Conference (2015, June 22)

The design of drug delivery systems (DDS) often requires biodegradable and biocompatible materials that allow safe retention and controlled drug release. In this respect, CaCO3 particles are appropriate ... [more ▼]

The design of drug delivery systems (DDS) often requires biodegradable and biocompatible materials that allow safe retention and controlled drug release. In this respect, CaCO3 particles are appropriate drug carriers that have excellent properties such as low density, high specific surface areas and porosity for drugs and proteins encapsulation. Here, degradable synthetic copolymers based on polyphosphoester (PPE) were used to template CaCO3 particles. PPE is a promising candidate due to its biocompatibility, biodegradability and low toxicity of its degradation products such as phosphates. In particular, PPE copolymers with carboxylic acid pendant groups and negatively charged polyphosphodiester-based copolymers were prepared by organocatalyzed ring opening polymerization (ROP) initiated from poly(ethylene oxide). The moieties introduced along the polymer chains enhance the calcium affinity and so the ability of the copolymers to tune the morphology of the CaCO3 particles. The copolymers were tested as templating agents for the preparation of CaCO3 particles by the classical chemical pathway and the supercritical CO2 (Sc-CO2) route. The morphology of the resulting particles was then compared to the one of particles obtained using hyaluronic acid (HA) as a templating agent. The synthesis involving Sc-CO2 and the copolymer with pendant carboxylic groups was particularly interesting and led to smaller (~1.5 µm) and non-aggregated particles. In the future, the impact of the copolymer structure and of the particle size on the encapsulation and release processes will be investigated. [less ▲]

Detailed reference viewed: 63 (12 ULg)
See detailOrganometallic-mediated radical polymerization for the precision design of novel poly(ionic liquid) copolymers
Cordella, Daniela ULg; Kermagoret, Anthony; Debuigne, Antoine ULg et al

Conference (2015, June 12)

In recent years, poly(ionic liquid)s (PIL)s were found to take an enabling role in important fields of polymer chemistry and material science. PILs combine the unique properties of ionic liquids with the ... [more ▼]

In recent years, poly(ionic liquid)s (PIL)s were found to take an enabling role in important fields of polymer chemistry and material science. PILs combine the unique properties of ionic liquids with the flexibility and properties of macromolecular architectures giving rise to a new family of functional polymers that opens new area of applications such as polymer electrolytes in electrochemical devices, powerful dispersants and stabilizers, absorbing membranes, precursors for carbon materials, porous polymers, etc. In this communication, we will report on the implementation of organometallic-mediated radical polymerization (OMRP) technique for the precision synthesis of unprecedented PILs (co)polymers. We will discuss how an organocobalt complex can efficiently control the growth of vinyl imidazolium chains and lead to PILs with predicted molar masses and low polydispersities under mild experimental conditions, which provide low temperatures (compared to the conventional radical polymerization techniques) and also the use of water as green polymerization medium. The huge potential of this system will be also highlighted by describing the one-pot synthesis of vinyl imidazolium-based block copolymers in heterogeneous conditions. This OMRP is unique for providing well-defined vinyl imidazolium based-copolymers opening for advanced PILs applications. [less ▲]

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See detailFluorinated alcohols as activators for the solvent-free chemical fixation of carbon dioxide onto epoxides
Gennen, Sandro ULg; Alves, Margot ULg; Méreau, Raphaël et al

in ChemSusChem (2015), 8(11), 1845-1849

The addition of fluorinated alcohols to onium salts provides highly efficient organocatalysts for the chemical fixation of CO2 onto epoxides under mild experimental conditions. The combination of online ... [more ▼]

The addition of fluorinated alcohols to onium salts provides highly efficient organocatalysts for the chemical fixation of CO2 onto epoxides under mild experimental conditions. The combination of online kinetic studies, NMR titrations and DFT calculations allows understanding this synergistic effect that provides an active organocatalyst for CO2/epoxides coupling. [less ▲]

Detailed reference viewed: 68 (20 ULg)
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See detailA new design of organic radical batteries (ORBs): carbon nanotube buckypaper electrode functionalized by electrografting
Aqil, Abdelhafid ULg; Vlad, Alexandru; Piedboeuf, Marie-Laure ULg et al

in Chemical Communications (2015), 51(45), 9301-9304

A novel hybridmaterial displaying a fast and reversible charge storage capability is prepared by electrografting of an alkoxyamine-bearing acrylate onto a carbon nanotube buckypaper, followed by the quan ... [more ▼]

A novel hybridmaterial displaying a fast and reversible charge storage capability is prepared by electrografting of an alkoxyamine-bearing acrylate onto a carbon nanotube buckypaper, followed by the quan- titative generation of an electroactive polynitroxide. [less ▲]

Detailed reference viewed: 78 (15 ULg)
See detailAliphatic polyphosphates, a promising class of polymers for drug delivery
Vanslambrouck, Stéphanie ULg; Clément, Benoit; Molin, Daniel G. et al

Conference (2015, June 02)

Detailed reference viewed: 22 (7 ULg)
See detailControlled synthesis of multi-functional polymers bearing pendant catechols for surface modifications
Patil, Nagaraj ULg; Aqil, Abdelhafid ULg; Jérôme, Christine ULg et al

Poster (2015, June)

Poly(ethylene glycol) (PEG)-based polymers have been widely employed in anti-fouling coating applications due to their robust bio-relevant properties including water solubility and biocompatibility ... [more ▼]

Poly(ethylene glycol) (PEG)-based polymers have been widely employed in anti-fouling coating applications due to their robust bio-relevant properties including water solubility and biocompatibility. However, limited by its poor adhesion towards surfaces, demands an addition modification strategies. Mussel adhesive proteins (MAPs) are potential models for adhesive polymers, which exhibits underwater adhesion towards dissimilar materials under environmentally challenging conditions. Most often experimentally simple, but structurally complex poly(dopamine) has been used as an analogues of MAPs for metal chelation, cross-linking and surface binding purposes. Inspired by MAPs, we have developed catechol-bearing copolymers for surface adhesion of stainless steel. This study describes the synthesis and reversible addition−fragmentation chain transfer (RAFT) polymerization of mussel-inspired acetonide-protected dopamine (meth)acrylamide monomers (ADA and ADMA). A series of well-defined P(PEGAm-b-ADAn) and P(ADMAn-b-PEGMAm) copolymers across a range of molar masses (13−42 kg/mol) with low molar mass dispersities (Đ = 1.12−1.25) were reported for the first time. Post polymerization TFA treatment yields block copolymers bearing free –catechol units in quantitative yields (>95%). The self-assembling nature of amphiphilic block-copolymers was studied by 1H-NMR, DLS and TEM. Surface functionalization and anti-fouling experiments were performed in real time using quartz crystal microbalance coupled with dissipation (QCM-D). The copolymer upon oxidation yields reactive quinones, which can be exploited to cross-link with chitosan (also, polymers with free –NH2 and –SH groups), thereby producing nano(macro)gels. In general, these novel class of block copolymeric ligand systems can be foreseen as versatile ingredients in material chemistry to obtain biocompatible multifunctional systems, benefited by high water solubility with inherent stealth ability and protein-repellency, as well as effective chelating groups, and may find application for a variety of biomedical fields, of which we have illustrated an important example. [less ▲]

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See detailDrug loading of sutures by supercritical CO2 impregnation: effect of polymer/drug interactions and thermal transitions
Champeau, Mathilde; Thomassin, Jean-Michel ULg; Tassaing, Thierry et al

in Macromolecular Materials and Engineering (2015), 300(6), 596-610

This paper aims at exploring the scCO2 impregnation of three commonly implanted polymer sutures made of poly-l-lactide (PLLA), poly(ethylene terephthalate) (PET) and polypropylene (PP) with two anti ... [more ▼]

This paper aims at exploring the scCO2 impregnation of three commonly implanted polymer sutures made of poly-l-lactide (PLLA), poly(ethylene terephthalate) (PET) and polypropylene (PP) with two anti-inflammatory drugs namely ketoprofen and aspirin. For all the investigated polymer/drug systems, the drug loading increases with temperature and pressure. It appears that two main criteria must be fulfilled by the polymer to achieve high drug loading: (i) a good affinity between the polymer and the drug and (ii) a high chain mobility to favor the diffusion of the drug into the matrix. As the investigated PLLA fulfills these two requirements, drug loading up to 32.5% with ketoprofen and 8.1% with aspirin has been achieved. [less ▲]

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See detailGold nanorods coated with mesoporous silica shell as drug delivery system for remote near infrared light-activated release and potential phototherapy
Liu, Ji; Detrembleur, Christophe ULg; De Pauw-Gillet, Marie-Claire ULg et al

in Small (Weinheim an der Bergstrasse, Germany) (2015), 11(19), 2323-2332

In this study, we report the synthesis of a nanoscaled drug delivery system, which is composed of a gold nanorod-like core and a mesoporous silica shell (GNR@MSNP) and partially uploaded with phase ... [more ▼]

In this study, we report the synthesis of a nanoscaled drug delivery system, which is composed of a gold nanorod-like core and a mesoporous silica shell (GNR@MSNP) and partially uploaded with phase-changing molecules (1-tetradecanol, TD, Tm 39 degrees C) as gatekeepers, as well as its ability to regulate the release of doxorubicin (DOX). Indeed, a nearly zero premature release is evidenced at physiological temperature (37 degrees C), whereas the DOX release is efficiently achieved at higher temperature not only upon external heating, but also via internal heating generated by the GNR core under near infrared irradiation. When tagged with folate moieties, GNR@MSNPs target specifically to KB cells, which are known to overexpress the folate receptors. Such a precise control over drug release, combining with the photothermal effect of GNR cores, provides promising opportunity for localized synergistic photothermal ablation and chemotherapy. Moreover, the performance in killing the targeted cancer cells is more efficient compared with the single phototherapeutic modality of GNR@MSNPs. This versatile combination of local heating, phototherapeutics, chemotherapeutics and gating components opens up the possibilities for designing multifunctional drug delivery systems. [less ▲]

Detailed reference viewed: 104 (19 ULg)