Search

Your search keyword '"Raphaël Riva"' showing total 17 results
Start Over Author "Raphaël Riva" Language english
17 results on '"Raphaël Riva"'

1. Accelerating the end-to-end production of cyclic phosphate monomers with modular flow chemistry

Author

Romain Morodo, Raphaël Riva, Nynke M. S. van den Akker, Daniel G. M. Molin, Christine Jérôme, Jean-Christophe M. Monbaliu, Fysiologie, and RS: Carim - V03 Regenerative and reconstructive medicine vascular disease

Subjects
BLOCK-COPOLYMERS, DELIVERY, POLYMERIZATION, POLY(ETHYLENE GLYCOL), ACID, PLATFORM, FUNCTIONALIZATION, General Chemistry, IN-VITRO, POLYPHOSPHOESTER, DRUG
Abstract

The biocompatibility, tunable degradability and broad functionalities of polyphosphoesters and their potential for biomedical applications have stimulated a renewed interest from Chemistry, Medicinal Chemistry and Polymer Sciences. Commercial applications of polyphosphoesters as biomaterials are still hampered because of the time and resource-intensive sourcing of their corresponding monomers, in addition to the corrosive and sensitive nature of their intermediates and by-products. Here, we present a groundbreaking challenge for sourcing the corresponding cyclic phosphate monomers by a different approach. This approach relies on the use of continuous flow technologies to intensify the end-to-end preparation of cyclic phosphate monomers with a semi-continuous modular flow platform. The applied flow technology mitigates both safety and instability issues related to the more classical production of cyclic phosphate monomers. The first flow module allows safe synthesis of a library of cyclic chlorophosphite building blocks and features in-line P-31 NMR real-time monitoring. After optimization on the microfluidic scale, this first module is successfully transposed toward mesofluidic scale with a daily throughput of 1.88 kg. Downstream of the first module, a second module is present, allowing the quantitative conversion of cyclic chlorophosphites with molecular oxygen toward chlorophosphate derivatives within seconds. The two modules are concatenable with a downstream semi-batch quench of intermediate chlorophosphate with alcohols, hence affording the corresponding cyclic phosphate monomers. Such a continuous flow setup provides considerable unprecedented advantages to safely and efficiently synthesize a library of versatile high value-added cyclic phosphate monomers at large scale. These freshly produced monomers can be successfully (co)polymerized, using either batch or flow protocols, into well-defined polyphosphoesters with assessed thermal properties and cytotoxicity.

Published
2022

2. Thiol-ene Reaction: An Efficient Tool to Design Lipophilic Polyphosphoesters for Drug Delivery Systems

Author

Stéphanie Vanslambrouck, Raphaël Riva, Bernard Ucakar, Véronique Préat, Mick Gagliardi, Daniel G. M. Molin, Philippe Lecomte, and Christine Jérôme

Subjects
click chemistry, biodegradable polymer, polyphosphoester, drug-delivery, Organic chemistry, QD241-441
Abstract

Poly(ethylene glycol)-b-polyphosphoester (PEG-b-PPE) block copolymer nanoparticles are promising carriers for poorly water soluble drugs. To enhance the drug loading capacity and efficiency of such micelles, a strategy was investigated for increasing the lipophilicity of the PPE block of these PEG-b-PPE amphiphilic copolymers. A PEG-b-PPE copolymer bearing pendant vinyl groups along the PPE block was synthesized and then modified by thiol-ene click reaction with thiols bearing either a long linear alkyl chain (dodecyl) or a tocopherol moiety. Ketoconazole was used as model for hydrophobic drugs. Comparison of the drug loading with PEG-b-PPE bearing shorter pendant groups is reported evidencing the key role of the structure of the pendant group on the PPE backbone. Finally, a first evidence of the biocompatibility of these novel PEG-b-PPE copolymers was achieved by performing cytotoxicity tests. The PEG-b-PPE derived by tocopherol was evidenced as particularly promising as delivery system of poorly water-soluble drugs.

Published
2021
Full Text
View/download PDF

4. Photo-Cross-Linkable Coumarin-Based Poly(ϵ-caprolactone) for Light-Controlled Design and Reconfiguration of Shape-Memory Polymer Networks

Author

Thomas Defize, Raphaël Riva, Christine Jérôme, Michaël Alexandre, Jean-Michel Thomassin, Gauthier Eppe, Cédric Malherbe, Heidi Ottevaere, Rachid Jellali, Brussels Photonics Team, and Applied Physics and Photonics

Subjects
chemistry.chemical_classification, Materials science, Polymers and Plastics, Organic Chemistry, Control reconfiguration, 02 engineering and technology, Shape-memory alloy, Polymer, 010402 general chemistry, 021001 nanoscience & nanotechnology, ϵ caprolactone, Coumarin, 01 natural sciences, 0104 chemical sciences, Polyester, Inorganic Chemistry, chemistry.chemical_compound, Shape-memory polymer, chemistry, Chemical engineering, Materials Chemistry, 0210 nano-technology
Abstract

Photochemically cross-linked shape-memory polymer (SMP) materials have been achieved by functionalizing chain-ends of star-shaped poly(ϵ-caprolactone) (PCL) with 7-hydroxypropoxy-4-methylcoumarin followed by photodimerization of these end-groups. The kinetics of the network formation in function of the photosensitizer concentration has been studied by swelling experiments and rheology. Thanks to the design of a dedicated homemade mold, highly reproducible irradiation conditions have been achieved allowing to study the network formation and properties, especially the shape-memory properties, in relation to the coumarin dimerization degree as determined by Raman spectroscopy. In optimized conditions, PCL-based SMP materials exhibiting high fixity and recovery have been achieved in remarkably short irradiation time, typically 5 min. In addition, the precise control of the network cross-link density with the irradiation time, so as the high stability of the formed networks toward temperature variations was also demonstrated allowing the fine-tuning of the network properties by the irradiation process. Finally, the reversible character of the coumarin dimerization under light irradiation of appropriate wavelength has been quantified by Raman spectroscopy. The dimer photocleavage allows the photoreconfiguration of the networks offering the ability to modify the "permanent" shape of the SMP material, while preserving the excellent shape-memory properties.

Published
2019
Full Text
View/download PDF

5. Hybrid Gd 3+ /cisplatin cross-linked polymer nanoparticles enhance platinum accumulation and formation of DNA adducts in glioblastoma cell lines

Author

Clément Tétaud, Philippe Lecomte, Bénédicte Lelièvre, Christine Jérôme, Raphaël Riva, Hélène Lajous, Frank Boury, François Hindré, Emmanuel Garcion, Sylvie Avril, Bernardo, Elizabeth, Design and Application of Innovative Local Treatments in Glioblastoma (CRCINA-ÉQUIPE 17), Centre de Recherche en Cancérologie et Immunologie Nantes-Angers (CRCINA), Université d'Angers (UA)-Université de Nantes (UN)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre hospitalier universitaire de Nantes (CHU Nantes)-Université d'Angers (UA)-Université de Nantes (UN)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre hospitalier universitaire de Nantes (CHU Nantes), Center for Education and Research on Macromolecules - CERM [Liège, Belgium], Université de Liège-CESAM RU [Liège, Belgium], Département de Pharmacologie-Toxicologie [CHU Angers], Centre Hospitalier Universitaire d'Angers (CHU Angers), PRES Université Nantes Angers Le Mans (UNAM)-PRES Université Nantes Angers Le Mans (UNAM), Plateforme de Radiobiologie et d’Imageries EXpérimentale [SFR ICAT - UA] (PRIMEX), SFR UA 4208 Interactions Cellulaires et Applications Thérapeutiques (ICAT), Université d'Angers (UA)-Université d'Angers (UA), This work was supported by the 'Institut National de la Santé et de la Recherche Médicale' (INSERM), by the University ofAngers (Angers, France) and by the University of Liège (Liege, Belgium). H. L. was a Ph.D. student from the EuropeanCommunity in the framework of the Erasmus Mundus JointDoctorate Program NanoFar and received a fellowship from 'La Région Pays-de-la-Loire'. P. L. is Research Associate of the FRS-FNRS. F. H., C. T. and E. G. are members of the LabEx IRON 'Innovative Radiopharmaceuticals in Oncology and Neurology' funded by the ANR (French National Research Agency) as part of the French government 'Investissements d’Avenir' programme. The presented work is also related to the PL-BIO 2014-2020 INCA (Institut National du Cancer) project MARENGO – 'MicroRNA agonist and antagonist Nanomedicines for GliOblastoma treatment: from molecular programmation to preclinical validation' and to the 'Réseau Vectorisation and Radiothérapies' and 'Réseau Gliome (ReGGO)' of the 'Cancéropôle Grand-Ouest'., Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Nantes - UFR de Médecine et des Techniques Médicales (UFR MEDECINE), Université de Nantes (UN)-Université de Nantes (UN)-Centre hospitalier universitaire de Nantes (CHU Nantes)-Centre National de la Recherche Scientifique (CNRS)-Université d'Angers (UA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Nantes - UFR de Médecine et des Techniques Médicales (UFR MEDECINE), Université de Nantes (UN)-Université de Nantes (UN)-Centre hospitalier universitaire de Nantes (CHU Nantes)-Centre National de la Recherche Scientifique (CNRS)-Université d'Angers (UA), Center for Education and Research on Macromolecules, Université de Liège, Groupe d'Étude des Interactions Hôte-Pathogène (GEIHP), Université d'Angers (UA), Génétique Diversité et Ecophysiologie des Céréales (GDEC), Institut National de la Recherche Agronomique (INRA)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020]), CESAM RU [Liège, Belgium]-Université de Liège, Plateforme de Radiobiologie et d’Imagerie EXperimentale - PRIMEX [Angers], Design and Application of Innovative Local Treatments in Glioblastoma (CRCINA - Département NOHMAD - Equipe 17), Centre de recherche de Cancérologie et d'Immunologie / Nantes - Angers (CRCINA), Université d'Angers (UA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre hospitalier universitaire de Nantes (CHU Nantes)-Université de Nantes - UFR de Médecine et des Techniques Médicales (UFR MEDECINE), Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre hospitalier universitaire de Nantes (CHU Nantes)-Université de Nantes - UFR de Médecine et des Techniques Médicales (UFR MEDECINE), Université de Nantes (UN)-Université de Nantes (UN), Groupe d'Etude des Interactions Hôte-Parasite (GEIHP), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de la Recherche Agronomique (INRA), and Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut National de la Recherche Agronomique (INRA)

Subjects
Cisplatin, Biodistribution, Chemistry, Gadolinium, [SDV]Life Sciences [q-bio], Biomedical Engineering, Nanoparticle, chemistry.chemical_element, [SDV.CAN]Life Sciences [q-bio]/Cancer, 02 engineering and technology, Prodrug, 021001 nanoscience & nanotechnology, Micelle, 03 medical and health sciences, 0302 clinical medicine, Targeted drug delivery, [SDV.CAN] Life Sciences [q-bio]/Cancer, 030220 oncology & carcinogenesis, medicine, Biophysics, Nanomedicine, General Materials Science, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS, medicine.drug
Abstract

International audience; Glioblastoma is the most frequent and aggressive primary malignant tumor of the central nervous system with a gloomy prognosis. Platinum derivatives and one among them, cisplatin, exhibited promising results when locally administered into the brain of glioblastoma bearing rats. Nanovectorization of anticancer agents through polymeric nanoparticles may even promote drug accumulation within cells, thus concentrating the drug efficiently at its target. Anchorage of gadolinium complexes on the corona of such smart drug delivery systems could further allow magnetic resonance imaging (MRI) monitoring of the nanoplat-form biodistribution in the damaged parenchyma and its therapeutic benefit. For this purpose, a biocom-patible amphiphilic triblock copolymer, made of degradable polyester and polycarbonate and bioelimin-able polyethylene oxide (PEO), was synthesized by successive ring-opening polymerizations. After micelli-zation in water, gadolinium complexes were grafted onto the PEO micelle corona and the carboxylate functions, located at the surface of the micelle's core, were able to cross-link with Pt(II) complexes. A macromolecular prodrug was therefore recovered in which more than one third of the carboxylate functions were linked to a platinum atom. By this strategy, stable cisplatin cross-linked nanoparticles were formulated with a mean size in the range of 100.63 ± 12.04 nm consistent with biological investigations. Relaxometry measurements both in water and in plasma at 7 T, 25 °C, confirmed the intrinsic potential of these hybrid nanoparticles as alternative MRI contrast agents with a substantial increase in the r 2 /r 1 ratio by a factor of 3.3 and 2.7, respectively, compared to the conventional low molar mass Gd-DTPA. As a result, their infusion within the striatum of glioblastoma-bearing mice resulted in a hypersignal on T 2-weighted MR images that persisted over time. Ultimately, the formulated prodrug exhibited up to 50-fold increased accumulation in human glioblastoma cell lines and up to 32-fold enhanced subsequent Pt-DNA adduct formation in comparison with free cisplatin, thus supporting the potential of this innovative bimodal tool for further applications.

Published
2018
Full Text
View/download PDF

6. Synthesis and tensioactive properties of PEO-b-polyphosphate copolymers

Author

Guy Broze, Philippe Lecomte, Daniel G. M. Molin, Raphaël Riva, Stéphanie Vanslambrouck, Benoît Clement, Christine Jérôme, Leo H. Koole, RS: CARIM - R3 - Vascular biology, Biomedische Technologie, and Fysiologie

Subjects
chemistry.chemical_classification, Ethylene oxide, General Chemical Engineering, Polyphosphate, Biomaterial, Nanoparticle, General Chemistry, Micelle, chemistry.chemical_compound, chemistry, Polymer chemistry, Copolymer, Pyrene, Alkyl
Abstract

Poly(ethylene oxide) (PEO)-b-polyphosphate copolymers made of hydrophilic PEO and hydrophobic polyphosphates are amphiphilic copolymers prone to self-assemble in water into nanoparticles. In this work, nanoparticles are obtained by the self-assembly of PEO-b-polyphosphate copolymers in water in the absence of any organic co-solvent whatever the length of the pendant alkyl chain (between 4 and 7 carbon atoms) of the polyphosphate block. Remarkably, this solvent-free process remains efficient even for the most hydrophobic polyphosphate blocks. The critical aggregation concentration (CAC) of the block copolymers was determined by pyrene probe fluorescence. Finally, the efficiency of these copolymer surfactants to decrease the air-water interface was measured by air-bubble tensiometry.

Published
2015
Full Text
View/download PDF

7. Implementation and Switching Behavior of a PCB-DBC IGBT Module Based on the Power Chip-on-Chip 3D Concept

Author

Raphaël Riva, Johan Delaine, Jean-Louis Marchesini, Cyril Buttay, Yvan Avenas, Pierre-Olivier Jeannin, Laboratoire de Génie Electrique de Grenoble (G2ELab), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Ampère, Département Energie Electrique (EE), Ampère (AMPERE), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-École Centrale de Lyon (ECL), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), IRT Saint Exupéry - Institut de Recherche Technologique, and Institut Carnot 'énergies du futur', Région Rhône-Alpes

Subjects
Engineering, Busbar, 02 engineering and technology, Capacitors, 01 natural sciences, Industrial and Manufacturing Engineering, law.invention, [SPI]Engineering Sciences [physics], law, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Electronic engineering, Electrical and Electronic Engineering, Inductance, 010302 applied physics, Substrates, business.industry, 020208 electrical & electronic engineering, Transistor, Electrical engineering, Logic gates, Insulated-gate bipolar transistor, Converters, Power (physics), Insulated gate bipolar transistors, Capacitor, Control and Systems Engineering, Logic gate, business, Switches, Copper
Abstract

International audience; With the emergence of new power semiconductor devices, the switching speeds in power converters are increasing. The stray inductances of switching cells must therefore be minimized to limit over-voltages on transistors. One relatively new approach, called Power Chip-on-Chip (PCoC), considers the integration of power dies, one on top of the other, directly in the busbar. This allows for the reduction of the stray inductance. This paper first presents the implementation of a PCoC module using classical packaging techniques. Then a description of the different technological steps for the realization is outlined. Finally, experimental characterization results confirm the lower stray inductances offered by the PCoC package compared with the planar one.

Published
2016
Full Text
View/download PDF

8. Silver sintering for power electronics integration

Author

Cyril Buttay, Bruno Allard, Raphaël Riva, Ampère, Département Energie Electrique (EE), Ampère (AMPERE), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-École Centrale de Lyon (ECL), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), IRT Saint Exupéry - Institut de Recherche Technologique, IMAPS, Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National des Sciences Appliquées de Lyon - INSA (FRANCE), Université Claude Bernard-Lyon I - UCBL (FRANCE), and IRT Saint Exupéry - Institut de Recherche Technologique (FRANCE)

Subjects
Energie électrique, Materials science, Assembly, chemistry.chemical_element, Sintering, 02 engineering and technology, Capacitors, 01 natural sciences, law.invention, [SPI]Engineering Sciences [physics], law, Power electronics, 0103 physical sciences, Thermal, Electronique, 010302 applied physics, Internet, Substrates, Metallurgy, Process (computing), 021001 nanoscience & nanotechnology, Copper, Capacitor, chemistry, Soldering, visual_art, Electronic component, visual_art.visual_art_medium, Electrical thermal performance Switches, 0210 nano-technology
Abstract

International audience; Silver sintering is an attractive alternative to soldering in power electronics, as it offers higher electrical and thermal performance. Furthermore, sintered attaches can operate at a higher temperature. In this paper, we investigate the use of silver sintering for the bonding of passive components, and for the manufacturing of so-called 3D-modules. It is shown that this technique is well suited, as it makes it possible to operate at very high temperature (up to 310 °C demonstrated), and as it simplifies the assembly process (several identical sintering steps can be performed successively without problem).

Published
2015
Full Text
View/download PDF

9. 3D Packaging Structure for High Temperature Power electronics

Author

Raphaël Riva, Cyril Buttay, Rémi Perrin, Marie-Laure Locatelli, Vincent Bley, Bruno Allard, Ampère, Département Energie Electrique (EE), Ampère (AMPERE), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-École Centrale de Lyon (ECL), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Matériaux Diélectriques dans la Conversion d’Energie (LAPLACE-MDCE), LAboratoire PLasma et Conversion d'Energie (LAPLACE), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, and IMAPS France

Subjects
[SPI.NRJ]Engineering Sciences [physics]/Electric power
Abstract

International audience; This paper presents a so-called "3D power packaging structure", in which silicon-carbide power devices are placed between two ceramic-metal substrates (DBC). This allows for more efficient cooling of the transistors (double side cooling), better electrical performance (lower resistance and inductance), and higher level of integration. The paper presents the manufacturing steps required to produce and assemble the different parts of the module: The substrates are etched with a high-resolution, two step process which exceeds the common design rules. The module is assembled using silver sintering. A new approach is used for the encapsulation of this intricate structure: parylene HT.Some of these results were published in the IMAPS HiTEC conference in may 2014. For this presentation, we will focus on new results: the electrical characterization (static and dynamic) of the power module. A half-bridge module, using two SiC JFET transistors is used for these tests.

Published
2014

10. Direct Route to Well-Defined Poly(ionic liquid)s by Controlled Radical Polymerization in Water

Author

Christophe Detrembleur, Daniel Taton, Christine Jérôme, Ian German, Mehmet Isik, Raphaël Riva, Antoine Debuigne, Anthony Kermagoret, David Mecerreyes, Daniela Cordella, Univ Liege, Dept Chem, CERM, Université de Liège-CERM, Univ Basque Country UPV EHU, Joxe Mari Korta Ctr, POLYMAT, Univ Basque Country, Laboratoire de Chimie des Polymères Organiques (LCPO), Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), Team 1 LCPO : Polymerization Catalyses & Engineering, and Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)

Subjects
AMBIENT-TEMPERATURE, Polymers and Plastics, METHACRYLATE, Radical polymerization, Dispersity, CLICK CHEMISTRY POLYADDITION, SOLUBLE (CO)POLYMERS, AQUEOUS RAFT POLYMERIZATION, Inorganic Chemistry, chemistry.chemical_compound, Polymer chemistry, Materials Chemistry, Reversible addition−fragmentation chain-transfer polymerization, VINYL-ACETATE, IONIC LIQUID, Molar mass, Chemistry, HYDROPHILIC BLOCK-COPOLYMERS, Organic Chemistry, DIBLOCK COPOLYMERS, [CHIM.POLY]Chemical Sciences/Polymers, Monomer, Cobalt-mediated radical polymerization, N-BUTYL ACRYLATE, Ionic liquid, Ionic polymerization
Abstract

International audience; The precision synthesis of poly(ionic liquid)s (PILs) in water is achieved for the first time by the cobalt-mediated radical polymerization (CMRP) of N-vinyl-3-alkylimidazolium-type monomers following two distinct protocols. The first involves the CMRP of various 1-vinyl-3-alkylimidazolium bromides conducted in water in the presence of an alkyl cobalt(III) complex acting as a monocomponent initiator and mediating agent. Excellent control over molar mass and dispersity is achieved at 30 degrees C. Polymerizations are complete in a few hours, and PIL chain-end fidelity is demonstrated up to high monomer conversions. The second route uses the commercially available bis(acetylacetonato)cobalt(II) (Co(acac)2) in conjunction with a simple hydroperoxide initiator (tertbutyl hydroperoxide) at 30, 40, and 50 degrees C in water, facilitating the scaling-up of the technology. Both routes prove robust and straightforward, opening new perspectives onto the tailored synthesis of PILs under mild experimental conditions in water.

Published
2014
Full Text
View/download PDF

11. Thermal stability of SiC JFETs in conduction mode

Author

Florent Morel, Raphaël Riva, Remy Ouaida, Dominique Bergogne, Bruno Allard, Cyril Buttay, Christophe Raynaud, Ampère (AMPERE), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Ampère, Département Energie Electrique (EE), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-École Centrale de Lyon (ECL), FRAE, and EPAHT

Subjects
JFET, Test bench, Materials science, High temperature electronics, 02 engineering and technology, Silicon carbide, 01 natural sciences, chemistry.chemical_compound, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Electronic engineering, Power semiconductor device, Silicon bandgap temperature sensor, 010302 applied physics, business.industry, 020208 electrical & electronic engineering, [SPI.NRJ]Engineering Sciences [physics]/Electric power, Wide-bandgap semiconductor, Atmospheric temperature range, Reliability, chemistry, Thermal design, Optoelectronics, Junction temperature, business
Abstract

8 pages; International audience; Although they can operate at elevated junction temperature, silicon carbide power devices can in some cases fail, even at low ambient temperature. This destruction mechanism, called the thermal run-away, is described in the paper. Then, the sensitivity of normally-on SiC JFETs (SiCED) to this mechanism is evaluated using a model based on experimental measurements performed over a wide temperature range (from -50°C to 300°C). It is shown that above a certain current level, run-away can occur. An experimental test bench is used to validate the modelling and explore the safe-operating area of these devices. The measurements confirm the sensitivity of the device to thermal run-away. Mitigation techniques are discussed.

Published
2013
Full Text
View/download PDF

12. Tocol modified glycol chitosan for the oral delivery of poorly soluble drugs

Author

Pierre Guillet, Véronique Préat, Jean-François Gohy, Julien Rolland, Raphaël Riva, Christine Jérôme, Jean-Marc Schumers, Nicolas Duhem, Pisciculture Expérimentale INRA des Monts d'Arrée (PEIMA), Institut National de la Recherche Agronomique (INRA), Ampère, École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie Bioorganique et des Systèmes Moléculaires Vectoriels (LCBOSMV), Avignon Université (AU), Center for Education and Research on Macromolecules, Université de Liège, Université Catholique de Louvain (UCL), Advanced Drug Delivery and Biomaterials [Brussels, Belgium], Louvain Drug Research Institute (LDRI)-Université Catholique de Louvain, Ampère (AMPERE), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université Catholique de Louvain = Catholic University of Louvain (UCL), and Université Catholique de Louvain = Catholic University of Louvain (UCL)-Louvain Drug Research Institute (LDRI)

Subjects
[SDV.BIO]Life Sciences [q-bio]/Biotechnology, Cell Survival, Surface Properties, Chemistry, Pharmaceutical, Drug Compounding, Administration, Oral, Tocopherols, Pharmaceutical Science, 02 engineering and technology, Microscopy, Atomic Force, 010402 general chemistry, 01 natural sciences, Micelle, Permeability, Chitosan, chemistry.chemical_compound, Microscopy, Electron, Transmission, [SDV.SP.MED]Life Sciences [q-bio]/Pharmaceutical sciences/Medication, medicine, Humans, Technology, Pharmaceutical, Organic chemistry, [CHIM]Chemical Sciences, Tocopherol, Intestinal Mucosa, Particle Size, Solubility, Micelles, ComputingMilieux_MISCELLANEOUS, Drug Carriers, Aqueous solution, Dose-Response Relationship, Drug, Chemistry, Permeation, [SDV.SP]Life Sciences [q-bio]/Pharmaceutical sciences, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Kinetics, Ketoconazole, [CHIM.POLY]Chemical Sciences/Polymers, Critical micelle concentration, Caco-2 Cells, Itraconazole, 0210 nano-technology, medicine.drug, Nuclear chemistry
Abstract

The aim of this study was to develop tocol derivatives of chitosan able (i) to self-assemble in the gastrointestinal tract and (ii) to enhance the solubility of poorly soluble drugs. Among the derivatives synthesized, tocopherol succinate glycol chitosan (GC-TOS) conjugates spontaneously formed micelles in aqueous solution with a critical micelle concentration of 2 μg mL(-1). AFM and TEM analysis showed that spherical micelles were formed. The GC-TOS increased water solubility of 2 model class II drugs. GC-TOS loading efficiency was 2.4% (w/w) for ketoconazole and 0.14% (w/w) for itraconazole, respectively. GC-TOS was non-cytotoxic at concentrations up to 10 mg mL(-1). A 3.4-fold increase of the apparent permeation coefficient of ketoconazole across a Caco-2 cell monolayer was demonstrated. Tocol polymer conjugates may be promising vehicles for the oral delivery of poorly soluble drugs.

Published
2012
Full Text
View/download PDF

13. In vivo biocompatibility of three potential intraperitoneal implants

Author

Sylvie, Defrère, Mélanie, Mestagdt, Raphaël, Riva, Fabrice, Krier, Anne, Van Langendonckt, Pierre, Drion, Christine, Jérôme, Brigitte, Evrard, Jean-Paul, Dehoux, Jean-Michel, Foidart, Jacques, Donnez, UCL - SSS/IREC/GYNE - Pôle de Gynécologie, and UCL - (SLuc) Service de gynécologie et d'andrologie

Subjects
Inflammation, Polydimethylsiloxane, Poly(hydroxyethyl methacrylate) (polyHEMA), Fibrinogen, Implant, Biocompatible Materials, Prostheses and Implants, Macaca mulatta, Rats, C-Reactive Protein, Materials Testing, Animals, Polyvinyls, Female, Biocompatibility, Rabbits, Dimethylpolysiloxanes, Rats, Wistar, Inflammation Mediators, Poly(ethylene-co-viny acetate) (PEVA), Peritoneal Cavity, Polyhydroxyethyl Methacrylate
Abstract

The intraperitoneal biocompatibility of PDMS, polyHEMA and pEVA was investigated in rats, rabbits and rhesus monkeys. No inflammation was evidenced by hematological analyses and measurement of inflammatory markers throughout the experiment and by post-mortem examination of the pelvic cavity. After 3 or 6 months, histological analysis revealed fibrous tissue encapsulating PDMS and PEVA implants in all species and polyHEMA implants in rabbits and monkeys. Calcium deposits were observed inside polyHEMA implants. The intraperitoneal biocompatibility of all 3 polymers makes them suitable for the design of drug delivery systems, which may be of great interest for pathologies confined to the pelvic cavity.

Published
2011

14. First example of “click” copper(i) catalyzed azide-alkyne cycloaddition in supercritical carbon dioxide: application to the functionalization of aliphatic polyesters.

Author

Bruno Grignard, Stephanie Schmeits, Raphaël Riva, Christophe Detrembleur, Philippe Lecomte, and Christine Jérôme

Subjects
CARBON dioxide, ALIPHATIC compounds, POLYESTERS, RING formation (Chemistry), COPPER catalysts, CHEMICAL reactions, EXTRACTION (Chemistry)
Abstract

The modification of aliphatic polyesters by the copper(i) catalyzed azide-alkyne cycloaddition (CuAAC) was successfully implemented in supercritical carbon dioxide (scCO2). Due to the remarkable properties of scCO2, the CuAAC reaction turned out to be quantitative even though the aliphatic polyesters used in this work were insoluble in scCO2Interestingly enough, the conditions were mild enough to prevent polymer degradation from occurring and finally, efficient removal of the catalyst (>96%) was achieved by scCO2extraction. [ABSTRACT FROM AUTHOR]

Published
2009
Full Text
View/download PDF

15. Combination of Ring-Opening Polymerization and “Click” Chemistry for the Synthesis of an Amphiphilic Tadpole-Shaped Poly(-Caprolactone) Grafted by PEO.

Author

Haiying Li, Raphaël Riva, Robert Jérôme, and Philippe Lecomte

Subjects
*RING-opening polymerization, *POLYETHYLENE oxide, *MACROCYCLIC compounds, *POLYMERIZATION
Abstract

A tadpole shaped poly(-caprolactone) (PCL; Mn24 500) was made amphiphilic by grafting the two PCL tails with PEO. In the first step, a macrocyclic PCL was synthesized by ring-opening polymerization of -caprolactone (CL) initiated by a cyclic tin(IV) dialkoxide and stabilized by local intramolecular photo-cross-linking. In the second step, the polymerization of a mixture of CL and -chloro--caprolactone (ClCL) was resumed with formation of two activated chloride containing PCL tails. In the third step, the chlorides were converted into azides onto which alkynyl end-capped PEO was grafted by the copper-mediated Huisgen's cycloaddition 3 2, thus giving a “click” reaction. The thermal properties of the final copolymer and the precursors were analyzed by differential scanning calorimetry. The amphiphilicity of the final copolymer was confirmed by micellization in water. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

16. Combination of Ring-Opening Polymerization and “Click Chemistry”:  Toward Functionalization and Grafting of Poly(-caprolactone).

Author

Raphaël Riva, Stéphanie Schmeits, Christine Jérôme, Robert Jérôme, and Philippe Lecomte

Subjects
*RING-opening polymerization, *ALKYNES, *CHEMICAL reactions, *POLYMERIZATION
Abstract

A straightforward strategy is proposed for the derivatization of poly(-caprolactone) (PCL). First, statistical copolymerization of -chloro--caprolactone (ClCL) with -caprolactone (CL) was initiated by 2,2-dibutyl-2-stanna-1,3-dioxepane (DSDOP). In a second step, pendent chlorides were converted into azides by reaction with sodium azide. Finally, duly substituted terminal alkynes were reacted with pendent azides by copper-catalyzed Huisgen's 1,3-dipolar cycloaddition, thus a “click” reaction. According to this strategy, pendent hydroxyl and acrylate groups and atom transfer radical polymerization (ATRP) initiators were successfully attached to PCL. Similarly, amphiphilic graft copolymers were prepared by cycloaddition of an alkyne end-capped poly(ethylene oxide) (PEO) onto the azide substituents of the copolyester. The dependence of the grafting yield on the experimental conditions of the “click” reaction, i.e., temperature, solvent, and catalyst, was investigated. This strategy is very versatile because a large variety of aliphatic polyesters can be easily synthesized from a single precursor, easily prepared from commercially available compounds, merely by changing the alkyne involved in the Huisgen's 1,3-dipolar cycloaddition. Last but not least, PCL subsituted by azide groups does not have to be isolated after substitution of chlorides by sodium azide, and the “click” reaction can be carried out in a “one-pot” process. [ABSTRACT FROM AUTHOR]

Published
2007
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results