References of "Benoit, Jean-Pierre"
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See detailpH-responsive flower-type micelles formed by a biotinylated poly(2-vinylpyridine)-block-poly(ethylene-oxide)-block-poly(ε-caprolactone) triblock copolymer
Van Butsele, Kathy ULg; Cajot, Sébastien ULg; Van Vlierberghe, Sandra et al

in Advanced Functional Materials (2009), 19(9), 1416-1425

In the present work, a method is proposed to assemble pH-responsive, flower-like micelles that can expose a targeting unit at their periphery upon a decrease in pH. The micelles are composed of a novel ... [more ▼]

In the present work, a method is proposed to assemble pH-responsive, flower-like micelles that can expose a targeting unit at their periphery upon a decrease in pH. The micelles are composed of a novel biotinylated triblock copolymer of poly(-caprolactone)-block-poly(ethylene oxide)-block-poly(2-vinylpyridine) (PCL-b-PEO-b-P2VP) and the non-biotinylated analogue. The block copolymers are synthesized by sequential anionic and ring-opening polymerization. The pH-dependent micellization behaviour in aqueous solution of the triblock copolymers developed is studied using dynamic light scattering, zeta potential, transmission electron microscopy (TEM), and fluorimetric measurements. The shielding of the biotin at neutral pH and their availability at the micelle surface upon protonation is established by TEM and surface plasmon resonance with avidin and streptavidin-coated gold surfaces. The preliminary stealthy behavior of these pH-responsive micelles is examined using the complement activation (CH50) test. [less ▲]

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See detailSynthesis and pH-dependent micellization of diblock copolymer mixtures
Van Butsele, Kathy ULg; Sibret, Pierre ULg; Fustin, Charles-André et al

in Journal of Colloid & Interface Science (2009), 329(2), 235-243

This work focused on the preparation and the aqueous solution properties of hybrid polymeric micelles consisting of a hydrophobic poly(ε-caprolactone) (PCL) core and a mixed shell of hydrophilic poly ... [more ▼]

This work focused on the preparation and the aqueous solution properties of hybrid polymeric micelles consisting of a hydrophobic poly(ε-caprolactone) (PCL) core and a mixed shell of hydrophilic poly(ethylene oxide) (PEO) and pH-sensitive poly(2-vinylpyridine) (P2VP). The hybrid micelles were successfully prepared by the rapid addition of acidic water to a binary solution of PCL34-b-PEO114 and PCL32-b-P2VP52 diblock copolymers in N,N-dimethylformamide. These micelles were pH-responsive as result of the pH-dependent ionization of the P2VP block. The impact of pH on the self-assembly of the binary mixture of diblocks—thus on the composition, shape, size and surface properties of the micelles—was studied by a variety of experimental techniques, i.e., dynamic and static light scattering, transmission electron microscopy, Zeta potential, fluorescence spectroscopy and complement hemolytic 50 test. [less ▲]

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See detailPEO coated magnetic nanoparticles for biomedical application
Aqil, Abdelhafid ULg; Vasseur, S.; Duguet, E. et al

in European Polymer Journal (2008), 44(10), 3191-3199

This paper reports on the preparation, characterization and stealthiness of superparamagnetic nanoparticles (magnetite Fe3O4) with a 5 nm diameter and stabilized in water (pH 6.5) by a shell of water ... [more ▼]

This paper reports on the preparation, characterization and stealthiness of superparamagnetic nanoparticles (magnetite Fe3O4) with a 5 nm diameter and stabilized in water (pH 6.5) by a shell of water-soluble poly(ethylene oxide) (PEO) chains. Two types of diblock copolymers, i.e., poly(acrylic acid)-b-poly(ethylene oxide), PAA–PEO, and poly(acrylic acid)-b-poly(acrylate methoxy poly(ethyleneoxide)), PAA–PAMPEO, were prepared as stabilizers with different compositions and molecular weights. At pH 6.5, the negatively ionized PAA block interacts strongly with the positively-charged nanoparticles, thus playing the role of an anchoring block. Aggregates of coated nanoparticles were actually observed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The hydrodynamic diameter was in the 50–100 nm range and the aggregation number (number of nanoparticles per aggregate) was lying between several tens and hundred. Moreover, the stealthiness of these aggregates was assessed “in vitro” by the hemolytic CH50 test. No response of the complement system was observed, such that biomedical applications can be envisioned for these magnetic nanoparticles. Preliminary experiments of magnetic heating (10 kA/m; 108 kHz) were performed and specific absorption rate varied from 2 to 13 W/g(Fe). [less ▲]

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See detailMagnetic nanoparticles coated by temperature responsive copolymers for hyperthermia
Aqil, Abdelhafid ULg; Vasseur, Sébastien; Duguet, Etienne et al

in Journal of Materials Chemistry (2008), 18(28), 3352-3360

Various temperature-responsive N-isopropylacrylamide-based functional copolymers were prepared and used for the stabilization of iron oxide nanoparticles. The copolymers investigated are poly(acrylic acid ... [more ▼]

Various temperature-responsive N-isopropylacrylamide-based functional copolymers were prepared and used for the stabilization of iron oxide nanoparticles. The copolymers investigated are poly(acrylic acid)-b-poly(N-isopropylacrylamide) (PAA-PNIPAM) and poly(acrylic acid)-b-poly(N-isopropylacrylamide)-b-poly(acrylate methoxy poly(ethylene oxide)) (PAA-PNIPAM-PAMPEO), with different molecular weights. The coated nanoparticles were characterized in terms of size by a combination of dynamic light scattering (DLS) and transmission electron microscopy (TEM). A sharp temperature transition was confirmed by particle size measurements vs. temperature. In addition, the stealthiness of the coated nanoparticles has been assessed in vitro by the haemolytic CH50 test. These measurements evidenced the crucial role of the PEO segments on the stealthiness of the nanoparticles and thus that such copolymers are particularly suitable for biomedical applications. Preliminary experiments of alternating magnetic field induced heating were performed and specific absorption rates of the various samples were recorded. [less ▲]

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See detailSynthesis of amphiphilic copolymers of poly(ethylene oxide) and poly(epsilon-caprolactone) with different architectures, and their role in the preparation of stealthy nanoparticles
Rieger, Jutta ULg; Passirani, Catherine; Benoît, Jean-Pierre et al

in Advanced Functional Materials (2006), 16(11), 1506-1514

Well-defined copolymers of biocompatible poly(epsilon-caprolactone) (PCL) and poly(ethylene oxide) (PEO) are synthesized by two methods. Graft copolymers with a gradient structure are prepared by ring ... [more ▼]

Well-defined copolymers of biocompatible poly(epsilon-caprolactone) (PCL) and poly(ethylene oxide) (PEO) are synthesized by two methods. Graft copolymers with a gradient structure are prepared by ring-opening copolymerization of epsilon-caprolactone (FCL) with a PEO macromonomer of the epsilon CL-type. The epsilon CL polymerization is initiated by a PEO macroinitiator to prepare diblock copolymers. These amphiphilic copolymers are used as stabilizers for biodegradable poly(DL-lactide) (PLA) nanoparticles prepared by a nanoprecipitation technique. The effect of the copolymer characteristic features (architecture, composition, and amount) on the nanoparticle formation and structure is investigated. The average size, size distribution, and stability of aqueous suspensions of the nanoparticles is measured by dynamic light scattering. For comparison, an amphiphilic random copolymer, poly(methyl methacrylate-co-methacrylic acid) (P(MMA-co-MA)), is synthesized. The stealthiness of the nanoparticles is analyzed in relation to the copolymer used as stabilizer. For this purpose, the activation of the complement system by nanoparticles is investigated in vitro using human serum. This activation is much less important whenever the nanoparticles are stabilized by a PEO-containing copolymer rather than by the P(MMA-co-MA) amphiphile. The graft copolymers with a gradient structure and the diblock copolymers with similar macromolecular characteristics (molecular weight and hydrophilicity) are compared on the basis of their capacity to coat PLA nanoparticles and to make them stealthy. [less ▲]

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