References of "Rieger, Jutta"
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See detailPegylated thermally responsive block copolymer micelles and nanogels via in situ RAFT aqueous dispersion polymerization
Rieger, Jutta ULg; Grazon, Chloé; Charleux, Bernadette et al

in Journal of Polymer Science. Part A, Polymer Chemistry (2009), 47(9), 2373-2390

A very straightforward approach was developed to synthesize pegylated thermoresponsive core-shell nanoparticles in a minimum of steps, directly in water. It is based on RAFT-controlled radical ... [more ▼]

A very straightforward approach was developed to synthesize pegylated thermoresponsive core-shell nanoparticles in a minimum of steps, directly in water. It is based on RAFT-controlled radical crosslinking copolymerization of N,N-diethylacrylamide (DEAAm) and N,N-methylene bisacrylamide (MBA) in aqueous dispersion polymerization. Because DEAAm is water-soluble and poly(N,N-diethylacrylamide) (PDEAAm) exhibits a lower critical solution temperature at 32 °C, the initial medium was homogeneous, whereas the polymer formed a separate phase at the reaction temperature. The first macroRAFT agent was a surface-active trithiocarbonate based on a hydrophilic poly(ethylene oxide) block and a hydrophobic dodecyl chain. It was further extented with N,N-dimethylacrylamide (DMAAm) to target macroRAFT agents with increasing chain length. All macroRAFT agents provided excellent control over the aqueous dispersion homopolymerization of DEAAm. When they were used in the radical crosslinking copolymerization of DEAAm and MBA, the stability and size of the resulting gel particles were found to depend strongly on the chain length of the macroRAFT agent, on the concentrations of both the monomer and the crosslinker, and on the process (one step or two steps). The best-suited experimental conditions to reach thermosensitive hydrogels with nanometric size and well-defined surface properties were determined. [less ▲]

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See detailPolyester nanoparticles presenting mannose residues : toward the development of new vaccine delivery systems combining biodegradability and targeting properties
Rieger, Jutta ULg; Freichels, Hélène ULg; Imberty, Anne et al

in Biomacromolecules (2009), 10(3), 651-657

We report the synthesis of fully biodegradable polymeric nanoparticles presenting mannose residues at their surface and their interaction with lectins. A simple and versatile method was used to reach the ... [more ▼]

We report the synthesis of fully biodegradable polymeric nanoparticles presenting mannose residues at their surface and their interaction with lectins. A simple and versatile method was used to reach the surface functionalization of poly(d,l-lactic acid) (PLA) nanoparticles by mannose moieties: It consists in using an amphiphilic mannosylated poly(ethylene oxide)-b-poly(-caprolactone) (PEO-b-PCL) diblock copolymer as a bioresorbable surface modifier in a simple nanoprecipitation-evaporation procedure. The size and zeta potential of the nanoparticles were found to depend on the molar copolymer/PLA ratio, demonstrating the influence of the copolymer on the formation of the nanoparticles. The bioavailability of the mannose residues as specific recognition sites on the nanoparticle surface could be demonstrated by a modified enzyme-linked lectin assay (ELLA) using biotin-labeled lectins which interact specifically with α-d-mannopyrannoside derivatives. Besides specific interaction by lectin−mannose complex formation, nonspecific adsorption of the proteins on the nanoparticle surface was observed. These results were fully supported by isothermal titration calorimetry experiments which suggested that the balance between specific and nonspecific interactions can be controlled by the amount of glycosylated polymer used for the preparation of the nanoparticles. Such nanoparticles are expected to be specifically recognized by mannose receptors, which are highly expressed in cells of the immune system. The targeting properties of these carrier systems combined with their potential adjuvant effects due to their size in the range of 200−300 nm make them attractive candidates as vaccine delivery systems. [less ▲]

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See detailThermally-responsive nanogels by RAFT-mediated aqueous dispersion polymerization
Rieger, Jutta ULg; Grazon, Chloé; Bui, Chuong et al

in PMSE preprints (2009), 101

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See detailAmphiphilic poly(ethylene oxide) macromolecular RAFT agent as a stabilizer and control agent in ab Initio batch emulsion polymerization
Rieger, Jutta ULg; Stoffelbach, François; Bui, Chuong et al

in Macromolecules (2008), 41(12), 4065-4068

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See detailMannosylated poly(ethylene oxide)-b-Poly(epsilon-caprolactone) diblock copolymers: Synthesis, characterization, and interaction with a bacterial lectin
Rieger, Jutta ULg; Stoffelbach, François; Cui, Di et al

in Biomacromolecules (2007), 8(9), 2717-2725

A novel bioeliminable amphiphilic poly(ethylene oxide)-b-poly(epsilon-caprolactone) (PEO-b-PCL) diblock copolymer end-capped by a mannose residue was synthesized by sequential controlled polymerization of ... [more ▼]

A novel bioeliminable amphiphilic poly(ethylene oxide)-b-poly(epsilon-caprolactone) (PEO-b-PCL) diblock copolymer end-capped by a mannose residue was synthesized by sequential controlled polymerization of ethylene oxide and epsilon-caprolactone, followed by the coupling of a reactive mannose derivative to the PEO chain end. The anionic polymerization of ethylene oxide was first initiated by potassium 2-dimethylaminoethanolate. The ring-opening polymerization of epsilon-caprolactone was then initiated by the omega-hydroxy end-group of PEO previously converted into an Al alkoxide. Finally, the saccharidic end-group was attached by quaternization of the tertiary amine (alpha-end-group of the PEO-b-PCL with a brominated mannose derivative. The copolymer was fully characterized in terms of chemical composition and purity by high-resolution NMR spectroscopy and size exclusion chromatography. Furthermore, measurements with a pendant drop tensiometer showed that both the mannosylated copolymer and the non-mannosylated counterpart significantly decreased the dichloromethane/water interfacial tension. Moreover, these amphiphilic copolymers formed monodisperse spherical micelles in water with an average diameter of similar to 11 nin as measured by dynamic light scattering and cryo-transmission electron microscopy. The availability of mannose as a specific recognition site at the surface of the micelles was proved by isothermal titration microcalorimetry (ITC), using the BclA lectin (from Burkholderia cenocepacia), which interacts selectively with a-D-mannopyranoside derivatives. The thermodynamic parameters of the lectin/mannose interaction were extracted from the ITC data. These colloidal systems have great potential for drug targeting and vaccine delivery systems. [less ▲]

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See detailPolymeric nanomaterials – synthesis, functionalization and applications in diagnosis and therapy
Rieger, Jutta ULg; Jérôme, Christine ULg; Jérôme, Robert ULg et al

in Kumar, Challa (Ed.) Nanomaterials for Medical Diagnosis and Therapy (2007)

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See detailHeterograft copolymers of poly(epsilon-caprolactone) prepared by combination of ATRA "grafting onto" and ATRP "grafting from" processes
Riva, Raphaël ULg; Rieger, Jutta ULg; Jérôme, Robert ULg et al

in Journal of Polymer Science. Part A, Polymer Chemistry (2006), 44(20), 6015-6024

This paper aims at reporting on the synthesis of a heterograft copolymer by combining the "grafting onto" process based on atom transfer radical addition (ATRA) and the "grafting from" process by atom ... [more ▼]

This paper aims at reporting on the synthesis of a heterograft copolymer by combining the "grafting onto" process based on atom transfer radical addition (ATRA) and the "grafting from" process by atom transfer radical polymerization (ATRP). The statistical copolymerization of epsilon-caprolactone (epsilon-CL) and alpha-chloro-epsilon-caprolactone (alpha-Cl-epsilon-CL) was initiated by 2,2-dibutyl-2-stanna-1,3-dioxepane (DSDOP), followed by ATRA of parts of the chlorinated units of poly(alpha-Cl-epsilon-CL-co-epsilon CL) on the terminal double bond of alpha-MeO,omega-CH2=CH-CH2-CO2-poly(ethylene oxide) (PEO). The amphiphilic poly(epsilon CL-g-EO) graft copolymer collected at this stage forms micelles as supported by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The unreacted pendant chloro groups of poly(epsilon-CL-g-EO) were used to initiate the ATRP of styrene with formation of copolymer with two populations of randomly distributed grafts, that is PEO and polystyrene [less ▲]

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See detailControlled synthesis and interface properties of new amphiphilic PCL-g-PEO copolymers
Rieger, Jutta ULg; Dubois, Philippe ULg; Jérôme, Robert ULg et al

in Langmuir (2006), 22(18), 7471-7479

Novel biodegradable and biocompatible poly(epsilon-caprolactone)-graft-poly(ethylene oxide), PCL-g-PEO, copolymers consisting of biocompatible blocks have been synthesized by ring-opening copolymerization ... [more ▼]

Novel biodegradable and biocompatible poly(epsilon-caprolactone)-graft-poly(ethylene oxide), PCL-g-PEO, copolymers consisting of biocompatible blocks have been synthesized by ring-opening copolymerization of epsilon-caprolactone (epsilon CL) and a poly(ethylene oxide) (PEO) macromonomer, i.e., PEO end-capped by an epsilon-caprolactone unit (gamma PEO.CL). The control is effective on the composition and length of both the hydrophobic polyester backbone and the hydrophilic PEO grafts. The reactivity ratios have been determined by monitoring the copolymer composition in relation to the comonomer conversion. The PCL-g-PEO copolymers have a tapered (gradient) rather than a random structure consistent with r(epsilon)CL = 3.95 and r(gamma)PEO.CL = 0.05. The amphiphilic graft copolymers display surfactant properties similar to those of PEO-b-PCL diblock copolymers of comparable composition and solubility, as supported by CHCl3/water interfacial tension measured by the pendant drop method. [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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See detailNew prospects for the grafting of functional groups onto aliphatic polyesters. Ring-opening polymerization of alpha- or gamma-substituted epsilon-caprolactone followed by chemical derivatization of the substituents
Lecomte, Philippe ULg; Riva, Raphaël ULg; Schmeits, Stephanie ULg et al

in Macromolecular Symposia (2006), 240

Recent progress in the synthesis of aliphatic polyesters, substituted by pendent functional groups, has been reviewed. Two main strategies have to be distinguished. The first route consists of the ring ... [more ▼]

Recent progress in the synthesis of aliphatic polyesters, substituted by pendent functional groups, has been reviewed. Two main strategies have to be distinguished. The first route consists of the ring-opening polymerization of F,caprolactone substituted by various functional groups, protected if needed, in alpha- or gamma-position. In a second strategy, the functional groups are grafted onto preformed polyesters chains in alpha-position of the carbonyl groups. alpha-chloro-epsilon-caprolactone is quite an interesting monomer because, after polymerization, the activated chloride can be easily derivatized by atom transfer radical addition and "click" chemistry, respectively. Similarly, gamma-acrylic-epsilon-caprolactone is precursor of (co)polyesters wellsuited to derivatization of the pendent double bonds by Michael addition. [less ▲]

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See detailDesign of stealth nanoparticles for drug delivery based on new amphiphilic copolymers
Rieger, Jutta ULg; Passirani, Catherine; Dubois, Philippe et al

Conference (2006, May 18)

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See detailControlled synthesis of an ABC miktoarm star-shaped copolymer by sequential ring-opening polymerization of ethylene oxide, benzyl beta-malolactonate, and epsilon-caprolactone
Rieger, Jutta ULg; Coulembier, Olivier; Dubois, Philippe ULg et al

in Macromolecules (2005), 38(26), 10650-10657

This paper reports on the synthesis of an amphiphilic miktoarm ABC star-shaped copolymer, s[(PEO)(PMLABz)(PCL)], consisting of biocompatible/bioresorbable arms. Indeed, PEO is a hydrophilic biocompatible ... [more ▼]

This paper reports on the synthesis of an amphiphilic miktoarm ABC star-shaped copolymer, s[(PEO)(PMLABz)(PCL)], consisting of biocompatible/bioresorbable arms. Indeed, PEO is a hydrophilic biocompatible poly(ethylene oxide) arm, PMLABz is a poly(benzyl beta-malolactonate) arm precursor of a pH-sensitive bioresorbable poly(beta-malic acid) block, and PCL is a hydrophobic bioresorbable poly(epsilon-caprolactone) arm. Each constitutive arm was prepared by ring-opening polymerization. A double-headed PEO macroinitiator [PEO-(OH)-COO-K+] was first prepared by selective hydrolysis of the alpha-lactone (2-oxepanone) end group of PEO chains end-capped by a omega-methoxy group. The anionic polymerization of benzyl beta-malolactonate (MLABz) was selectively initiated by the alpha-potassium carboxylate end group of PEO in the presence of 18-crown-6 ether. The polymerization of epsilon-caprolactone (epsilon-CL) was initiated by the hydroxyl group left at the junction of the two blocks of the as-prepared PEO-b-PMLABz diblock copolymer, in the presence of tin(II) bis(2-ethylhexanoate) (Sn(Oct)(2)). The macroinitiator, the intermediate diblock, and the final miktoarm. star-shaped copolymer were analyzed by H-1 NMR spectroscopy and size exclusion chromatography. [less ▲]

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See detailFunctionlization of biodegradable aliphatic polyesters by mannose-residue for the design of surface-modified polymeric nanoparticles
Rieger, Jutta ULg; Stoffelbach, François; Stoilova, Olya et al

Conference (2005, June 01)

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See detailSynthesis of novel functional PEO as builiding block for biomaterials
Rieger, Jutta ULg; Bernaerts, K.; Qiiu, Hongjin et al

Poster (2005, June 01)

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See detailVersatile functionalization and grafting of poly(epsilon-caprolactone) by Michael-type addition
Rieger, Jutta ULg; Van Butsele, Kathy ULg; Lecomte, Philippe ULg et al

in Chemical Communications (2005), (2), 274-276

The Michael-type addition of aliphatic (co)polyesters onto gamma-acryloyloxy epsilon-caprolactone units is a very straightforward technique of functionalization and grafting, which is tolerant to a ... [more ▼]

The Michael-type addition of aliphatic (co)polyesters onto gamma-acryloyloxy epsilon-caprolactone units is a very straightforward technique of functionalization and grafting, which is tolerant to a variety of functional groups and does not require intermediate protection/deprotection steps. [less ▲]

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See detailLactone end-capped poly(ethylene oxide) as a new building block for biomaterials
Rieger, Jutta ULg; Bernaerts, Katrien V.; Du Prez, Filip E et al

in Macromolecules (2004), 37(26), 9738-9745

This paper reports on the synthesis of a novel poly(ethylene oxide) (PEO) macromonomer, which can be copolymerized with epsilon-caprolactone (epsilon-CL) by ring-opening polymerization (ROP). PEO chains ... [more ▼]

This paper reports on the synthesis of a novel poly(ethylene oxide) (PEO) macromonomer, which can be copolymerized with epsilon-caprolactone (epsilon-CL) by ring-opening polymerization (ROP). PEO chains end-capped by an epsilon-caprolactone unit (gammaPEO(.)CL) have been synthesized by living anionic ring-opening polymerization of ethylene oxide (EO) initiated by the potassium alkoxide of 1,4-dioxaspiro[4.5]decan-8-ol, followed by derivatization of the acetal into a ketone and the Baeyer-Villiger oxidation of the ketone into a lactone. The end-capping of PEO by epsilon-CL was assessed by FTIR, MALDI-TOF, and H-1 NMR spectroscopy. This type of macromonomer is a precursor of amphiphilic comblike copolymers consisting of a biodegradable hydrophobic backbone of poly-(epsilon-caprolactone) (PCL) and hydrophilic PEO grafts. Copolymerization of gammaPEO(.)CL with epsilon-CL was successfully initiated by aluminum alkoxide. [less ▲]

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See detailPLA-coated gold nanoparticles for the labeling of PLA biocarriers
Qiu, Hongjin; Rieger, Jutta ULg; Gilbert, Bernard ULg et al

in Chemistry of Materials (2004), 16(5), 850-856

POly-DL-lactide end-capped by a protected thiol was synthesized by bulk ring-opening polymerization (ROP) of DL-lactide initiated by the reaction product of aluminum isopropoxide [Al (iOPr) (3)] with ... [more ▼]

POly-DL-lactide end-capped by a protected thiol was synthesized by bulk ring-opening polymerization (ROP) of DL-lactide initiated by the reaction product of aluminum isopropoxide [Al (iOPr) (3)] with alpha- (2,4-dinitrophenylsulfenyl) ethanol. After the thiol deprotection, PLA-SH was used to stabilize gold nanoparticles. Either these nanoparticles were prepared in the presence of PLA-SH, or PLA-SH was substituted for part of the undecanethiol (C11SH) that stabilized preformed gold nanoparticles. In contrast to C11SH-coated nanoparticles, those stabilized by PLA-SH were successfully entrapped into 100-nm PLA nanocarriers prepared by nanoprecipitation. This is an easy technique to label PLA biocarriers and therefore trace their fate in vivo. [less ▲]

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