References of "Debuigne, Antoine"
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See detailProtein encapsulation and release from PEO-b-polyphosphoester templated calcium carbonate particles
Ergül, Zeynep ULg; Cordonnier, Thomas; Debuigne, Antoine ULg et al

in International Journal of Pharmaceutics (2016), 513

Calcium carbonate particles are promising candidates as proteins carriers for their controlled delivery in the body. The present paper aims at investigating the protein encapsulation by in situ ... [more ▼]

Calcium carbonate particles are promising candidates as proteins carriers for their controlled delivery in the body. The present paper aims at investigating the protein encapsulation by in situ precipitation of calcium carbonate particles prepared by a process based on supercritical CO2 and using a new type of degradable well-defined double hydrophilic block copolymers composed of poly(ethylene oxide) and polyphosphoester blocks acting as templating agent for the calcium carbonate. For this study, lysozyme was chosen as a model for therapeutic protein for its availability and ease of detection. It was found that by this green process, loading into the CaCO3 microparticles with a diameter about 2 mm can be obtained as determined by scanning electron microscopy. A protein loading up to 6.5% active lysozyme was measured by a specific bioassay (Micrococcus lysodeikticus). By encapsulating fluorescent-labelled lysozyme (lysozyme-FITC), the confocal microscopy images confirmed its encapsulation and suggested a core–shell distribution of lysozyme into CaCO3, leading to a release profile reaching a steady state at 59% of release after 90 min. [less ▲]

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See detailAlkylcobalt as source of radicals for the controlled polymerization of less activated vinyl monomer
Demarteau, Jérémy ULg; Cordella, Daniela ULg; Kermagoret, Anthony et al

Poster (2016, October 13)

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See detailOrganocobalt complexes as source of radicals for the controlled polymerization of unconjugated monomers
Demarteau, Jérémy ULg; Cordella, Daniela ULg; Kermagoret, Anthony et al

Poster (2016, September 12)

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See detailPolyphosphoester containing amphiphilic block copolymers as drug nanocarriers
Ergül, Zeynep ULg; Vanslambrouck, Stéphanie; Thiry, Justine ULg et al

Poster (2016, September 12)

The design of drug delivery systems often requires biodegradable and biocompatible materials that allow safe retention and controlled release of the drug. In this respect, supramolecularly self-assembled ... [more ▼]

The design of drug delivery systems often requires biodegradable and biocompatible materials that allow safe retention and controlled release of the drug. In this respect, supramolecularly self-assembled amphiphilic block copolymers into spherical micelles are appropriate carriers for poorly soluble drugs. In that framework, we have designed novel functional poly(ethylene oxide)-b-polyphosphoester amphiphilic block copolymers able to cross-linked under UV and degrade in response to a reduction of the pH from neutral conditions. Therefore, an unsaturated alkene side-chain was introduced on the cyclic phosphate monomer according to a one-step reaction followed by its organocatalyzed polymerization initiated by a poly(ethylene oxide) macroinitiator. After self-assembly into water, the micelles were cross-linked by UV irradiation. Then, these cross-linked micelles have been loaded by doxorubicin, i.e. a drug used in cancer therapy. We observed that the doxorubicin loading increased with the number of double bonds on the polyphosphate block of non-cross-linked micelles. This diblock amphiphilic copolymer bearing pendant unsaturations appears thus particularly promising candidate to build micellar drug delivery systems for intravenous injection. [less ▲]

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See detailMacro- and near-mesoporous monoliths by medium internal phase emulsion polymerization: a systematic study
Mathieu, Kevin ULg; Jérôme, Christine ULg; Debuigne, Antoine ULg

in Polymer (2016), 99

The synthesis of a series of poly(ethylene oxide)-b-polystyrene copolymers with different block lengths was performed by radical addition fragmentation chain transfer. These amphiphilic copolymers were ... [more ▼]

The synthesis of a series of poly(ethylene oxide)-b-polystyrene copolymers with different block lengths was performed by radical addition fragmentation chain transfer. These amphiphilic copolymers were tested as stabilizers for water-in-oil medium internal phase emulsion (MIPE) templating polymerization and the formation of polyMIPEs with controlled morphology. Aside from the structure of the emulsion stabilizer, several parameters susceptible to influence the size of the cavities and the interconnectivity of the porous monoliths were probed including the choice of the comonomers, treatment of the emulsion by ultrasound, the use of controlled radical polymerization method for the network formation as well as interfacial initiation. Interconnected cellular monoliths were produced. The polymerization of the ultrasonicated water-in-ethylhexylacrylate/divinylbenzene MIPE notably led to near-mesoporous open-cell material. Mechanical properties and specific surface areas of the polyMIPEs were also investigated and discussed. [less ▲]

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See detailControlled synthesis of poly(vinylamine)-based copolymers by organometallic-mediated radical polymerization
Dréan, Mathilde ULg; Guégan, Philippe; Detrembleur, Christophe ULg et al

in Macromolecules (2016), 49(13), 4817-4827

iving/controlled polymerization methods have enabled the synthesis of numerous (co)polymers with defined compositions and architectures. However, the precision design of poly(vinylamine)-based copolymers ... [more ▼]

iving/controlled polymerization methods have enabled the synthesis of numerous (co)polymers with defined compositions and architectures. However, the precision design of poly(vinylamine)-based copolymers remains challenging despite their extensive use in various fields of applications and the clear benefits to finely tune their properties. Here, we report on a two-step strategy for the synthesis of tailor-made poly(vinylamine) derivatives through the organometallic- mediated radical (co)polymerization (OMRP) of N-vinyl- acetamide and/or N-methylvinylacetamide followed by acid hydrolysis of the acetamide groups. A series of well-defined homopolymers as well as statistical and block copolymers with pendant primary and/or secondary amines having controlled molar masses, compositions, and low dispersities were produced accordingly. The reactivity ratios of the comonomers as well as the composition drift along the chain were determined in order to have a precise idea of the polymer structures. These advances represent a significant step toward an efficient platform for synthesis of this important class of amino group-containing (co)polymers. [less ▲]

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See detailPolyphosphoesters as a new platform for the design of particulate drug delivery systems
Vanslambrouck, Stéphanie; Ergul Yilmaz, Zeynep; Debuigne, Antoine ULg et al

Conference (2016, June)

Thanks to their biocompatibility and degradability properties, polyphosphates are appealing polymers for biomedical applications. In contrast to aliphatic polyesters, such as poly(ε-caprolactone) and poly ... [more ▼]

Thanks to their biocompatibility and degradability properties, polyphosphates are appealing polymers for biomedical applications. In contrast to aliphatic polyesters, such as poly(ε-caprolactone) and poly(lactide), the pentavalency of the phosphorus atom allows the easy modification of the polyphosphate properties by simply adjusting the nature, the length and the functionality of the polyphosphate pendant groups. Therefore, macromolecular engineering of polyphosphoesters was applied to design well-defined architectures and functionalities adapted to drug nanocarriers. In a first approach, amphiphilic block copolymers are synthesized by organo-catalyzed ring-opening polymerization process for the synthesis of a range of PEO-b-polyphosphate bearing various pendant groups. Post-polymerization thiol-ene click reactions preformed on PEO-b-polyphosphate copolymers was also investigated to improve the hydrophobicity of the polyphosphate. The self-assembly of these PEO-b-polyphosphate copolymers into micelles was investigated, particularly, the effect of the nature of the polyphosphate pendant groups (i) on the micelles characteristics, (ii) on the encapsulation of a poorly soluble drug and (iii) on the drug release profile. The toxicity of the different amphiphilic block copolymers was also evaluated by live/dead cell viability assays. In a second approach, double hydrophilic copolymers based on polyphosphoesters have been used as templating agent for the synthesis of calcium carbonate particles. Indeed, the use of such microparticles is becoming more and more attractive in many fields especially for biomedical applications for which fine tuning of size, morphology and crystalline form of CaCO3 particles is crucial. Although some structuring compounds, like hyaluronic acid, give satisfying results, the control of the particle structure still has to be improved. To this end, we evaluated the CaCO3 structuring capacity of the well-defined double hydrophilic block copolymers composed of poly(ethylene oxide) and of a polyphosphoester segment with affinity for calcium like poly(phosphotriester)s bearing pendant carboxylic acids or poly(phosphodiester)s with a negatively charged oxygen atom on each repeating monomer unit. [less ▲]

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See detailSynthesis of novel poly(vinylamine)-based copolymers with controlled compositions
Dréan; Guégan, Philippe; Detrembleur, Christophe ULg et al

Poster (2016, May 23)

Metal binding, pH sensitivity and polyelectrolytes complexation are key characteristics of amine-containing polymers. Among them, poly(vinylamine)s presenting high amine densities are particularly useful ... [more ▼]

Metal binding, pH sensitivity and polyelectrolytes complexation are key characteristics of amine-containing polymers. Among them, poly(vinylamine)s presenting high amine densities are particularly useful in many fields such as coatings , water purification and gas membrane separation. The properties of such polymers strongly depend on the nature of the amines and can thus be adjusted by incorporating different types of amines along the backbone. In this perspective, we developed a strategy for synthesizing poly(vinylamine)-based (co)polymers containing primary and secondary amines as well as imidazole moieties in predictable proportions. First, radical (co)polymerizations of N-vinylacetamide, N-methylvinylacetamide and vinylimidazole were performed followed by deprotection of the amine functions via acidic hydrolysis of the pendant amides. We determined the reactivity ratios of each comonomer pairs and developed the corresponding Skeist’s model, allowing the prediction of the copolymer compositions and distributions. Following this straightforward approach, novel amine-containing copolymers with predictable and precise compositions were made available and should contribute in the future to the development of the above-mentioned applications. [less ▲]

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See detailTuning morphology and surface properties of emulsion-templated porous polymers by controlled radical polymerization
Mathieu, Kevin ULg; Jérôme, Christine ULg; Debuigne, Antoine ULg

Poster (2016, May 23)

Macroporous polymer monoliths with interconnected structures have attracted considerable interests in the last decades and sustain many applications in the fields of supported catalysis, chromatography ... [more ▼]

Macroporous polymer monoliths with interconnected structures have attracted considerable interests in the last decades and sustain many applications in the fields of supported catalysis, chromatography, microfluidic, water purification, membrane separation, tissue engineering, to name but a few. A very popular and straightforward synthetic approach for such open-cell polymers is the High Internal Phase Emulsion (HIPE) polymerization method. The latter consists in three steps: (i) stabilization of an emulsion in which an internal phase with a volume fraction higher than 74% is dispersed within a minor continuous phase containing a polymer network precursor, (ii) curing of the polymer phase by polymerization or crosslinking reactions, (iii) removal of the internal phase to release the porosity. The surface properties and morphology of the polyHIPEs are important features that must be controlled and adjusted for each applications. In this context, we prepared by controlled radical polymerization a series of well-defined amphiphilic copolymers having different hydrophilic-lipophilic balance (HLB) and chain-ends, used it as stabilizers for the emulsion-templated polymerizations and demonstrated the crucial effect of the structure of the macromolecular surfactant on the morphology of the polyHIPEs. Finally, the physical and chemical anchoring of the macromolecular surfactants at the surface pores were also considered for tuning the surface properties of the porous monoliths. [less ▲]

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See detailPolyphosphoester containing amphiphilic block copolymers as drug nanocarriers
Yilmaz-Ergül, Zeynep ULg; Vanslambrouck, Stéphanie; Thiry, Justine ULg et al

Poster (2016, May 23)

The design of drug delivery systems (DDS) often requires biodegradable and biocompatible materials that allow safe retention and controlled release of the drug. In this respect, poly(ethylene oxide)-b ... [more ▼]

The design of drug delivery systems (DDS) often requires biodegradable and biocompatible materials that allow safe retention and controlled release of the drug. In this respect, poly(ethylene oxide)-b-polyphosphoester amphiphilic block copolymers are known to self-assemble into polymer micelles when placed in water are appropriate drug carriers. In this work, an unsaturated alkene side-chain was introduced on the cyclic phosphate monomer according to a one-step reaction followed by its organocatalyzed polymerization initiated by a poly(ethylene oxide) macroinitiator. After self-assembly into water, the micelles were cross-linked by UV irradiation. Then, these cross-linked micelles have been loaded by doxorubicin, which is a drug to use in cancer therapy. We observed that the doxorubicin loading increased with the number of double bonds on the polyphosphate block of non-cross-linked micelles. This diblock amphiphilic copolymer bearing pendant unsaturations appears thus particularly promising candidate to build micellar drug delivery systems for intravenous injection. [less ▲]

Detailed reference viewed: 46 (8 ULg)
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See detailCobalt-mediated radical polymerization of vinyl acetate and acrylonitrile in supercritical carbon dioxide
Kermagoret; Chau, Ngoc Do Quyen; Grignard, Bruno ULg et al

in Macromolecular Rapid Communications (2016), 39(6), 539-544

Cobalt-mediated radical polymerization (CMRP) of vinyl acetate (VAc) is successfully achieved in supercritical carbon dioxide (scCO 2 ). CMRP of VAc is conducted using an alkyl-cobalt(III) adduct that is ... [more ▼]

Cobalt-mediated radical polymerization (CMRP) of vinyl acetate (VAc) is successfully achieved in supercritical carbon dioxide (scCO 2 ). CMRP of VAc is conducted using an alkyl-cobalt(III) adduct that is soluble in scCO2 . Kinetics studies coupled to visual observations of the polymerization medium highlight that the melt viscosity and PVAc molar mass ( Mn ) are key parameters that affect the CMRP in scCO2. It is noticed that CMRP is controlled for M n up to 10 000 g mol−1 , but loss of control is progressively observed for higher molar masses when PVAc precipitates in the polymerization medium. Low molar mass PVAc macroinitiator, prepared by CMRP in scCO2 , is then successfully used to initiate the acrylonitrile polymerization. PVAc-b-PAN block copolymer is collected as a free flowing powder at the end of the process although the dispersity of the copolymer increases with the reaction time. Although optimization is required to decrease the dispersity of the polymer formed, this CMRP process opens new perspectives for macromolecular engineering in scCO2 without the utilization of fluorinated comonomers or organic solvents. [less ▲]

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See detailFar beyond primary poly(vinylamine)s through free radical copolymerization and amide hydrolysis
Dréan, Mathilde ULg; Guégan, Philippe; Jérôme, Christine ULg et al

in Polymer Chemistry (2016), 7(1), 69-78

Due to their affinity for many supports, their pH responsiveness, metal binding capacity and polyelectro- lyte complexation, poly(vinylamine) derivatives have attracted attention for many applications ... [more ▼]

Due to their affinity for many supports, their pH responsiveness, metal binding capacity and polyelectro- lyte complexation, poly(vinylamine) derivatives have attracted attention for many applications including coatings, water purification, or gas membrane separation. Nevertheless, most of them possess only pendant primary amines despite the possible benefits of incorporating different amino groups along the chain. In this work, a straightforward and scalable synthesis route towards polymers bearing primary and secondary amines, as well as imidazole groups, is reported. The general strategy relies on the radical copolymerization of different vinylamides and vinyl imidazoles followed by the hydrolysis of the resulting poly(vinylamide) derivatives. Binary and ternary free radical copolymerizations of N-vinylacetamide (NVA), N-methyl vinylacetamide (NMVA) and 1-vinylimidazole (VIm) were investigated and the reactivity ratios for each copolymerization system were determined. Thanks to these values a series of statistical copolymers with predictable composition and low deviation over the chain distribution could then be synthesized. Finally, the acidic hydrolysis of the acetamide functions towards the corresponding amine was performed and optimized. Copolymers containing various pendant amino groups and with low dispersity in the chain composition could be obtained, which opens new perspectives for the above mentioned applications. [less ▲]

Detailed reference viewed: 85 (24 ULg)