Stimuli-responsive Magnetic Nanohybrids for Triggered Drug Release and Potential Tumor Treatment via Hyperthermia

Poster (2012, September 13)

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Thermally induced coupling of poly(thiophene)-based block copolymers prepared by Grignard metathesis polymerization: a straightforward route toward highly regioregular multiblock conjugated copolymers

in Macromolecules (2012), 45(17), 6796-6806

We report on a convenient and simple process to prepare highly regioregular poly(thiophene)-based multiblock copolymers by a novel thermally induced coupling reaction. Diblock copolymers of 3 ... [more ▼]

We report on a convenient and simple process to prepare highly regioregular poly(thiophene)-based multiblock copolymers by a novel thermally induced coupling reaction. Diblock copolymers of 3-hexylthiophene (3HT) and 2,5-dibromo-3-(2-(2-tetrahydropyranyl-2-oxy)ethyl)thiophene (THPET) end-capped by a nickel complex (Br-P3HT-b-PTHPET-Ni(dppp)Br) are first prepared using Ni(dppp)Cl2 as catalyst at 30 °C by Grignard metathesis polymerization (GRIM process). The coupling of these α-bromo, ω-Ni(dppp)Br telechelic diblock copolymers then occurs by heating the solution of the copolymer at 80 °C for a few hours without adding any additional reagent. Reactions are complete in only 10 min when heating the copolymer at 120 °C using microwaves. The deprotection of the alcohol groups of PTHPET blocks allows further modifications such as the incorporation of acrylates by esterification. AFM analysis on thin films shows the influence of the nature of side chains (protected alcohol or acrylate), the molecular weight, and the architecture (diblock or multiblock) of the copolymer on the supramolecular organization of the polythiophene chains. [less ▲]

Use of new surface active carbohydrate esters for the synthesis of polyhipes in supercritical CO2

Poster (2012, September 10)

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α-Acetal, ω-alkyne poly(ethylene oxide) as a versatile building block for the synthesis of glycoconjugated graft-copolymers suited for targeted drug delivery

in Bioconjugate Chemistry (2012), 23(9), 1740-1752

α-Acetal, ω-alkyne poly(ethylene oxide) was synthesized as building block of glycoconjugated poly(ε-caprolactone)-graft-poly(ethylene oxide) (PCL-g-PEO) copolymers. The alkyne group is indeed instrumental ... [more ▼]

α-Acetal, ω-alkyne poly(ethylene oxide) was synthesized as building block of glycoconjugated poly(ε-caprolactone)-graft-poly(ethylene oxide) (PCL-g-PEO) copolymers. The alkyne group is indeed instrumental for the PEGylation of a poly(α-azido-ε-caprolactone-co-ε-caprolactone) copolymer by the Huisgen’s 1,3 dipolar cycloaddition, i.e., a click reaction. Moreover, deprotection of the acetal end-group of the hydrophilic PEO grafts followed by reductive amination of the accordingly formed aldehyde with an aminated sugar is a valuable strategy of glycoconjugation of the graft copolymer, whose micelles are then potential. A model molecule (fluoresceinamine) was first considered in order to optimize the experimental conditions for the reductive amination. These conditions were then extended to the decoration of the graft copolymer micelles with mannose, which is a targeting agent of dendritic cells and macrophages. The bioavailability of the sugar units at the surface of micelles was investigated by surface plasmon resonance (SPR). The same question was addressed to nanoparticles stabilized by the graft copolymer. Enzyme linked lectin assay (ELLA) confirmed the availability of mannose at the nanoparticle surface. [less ▲]

Organometallic-mediated radical polymerization of vinyl amides: Effect of metal coordination

Conference (2012, September 04)

Photoresponsive coumarin-functionalized PDMS networks for controlling surface topography with light

Conference (2012, August 14)

Clickable PEG conjugate obtained by ‘‘clip’’ photochemistry: Synthesis and

in Journal of Fluorine Chemistry (2012), 140

In this paper, we describe a grafting methodology associated to a quantitative 19F NMR method (qNMR) for the conjugation of small molecules on a PEG building block aimed at click chemistry applications in ... [more ▼]

In this paper, we describe a grafting methodology associated to a quantitative 19F NMR method (qNMR) for the conjugation of small molecules on a PEG building block aimed at click chemistry applications in the domain of drug delivery systems. Acetylenic PEG (PEG-yne) was first derivatized with a fluorinated benzyl amine (TagF6) by means of photografting of a trifluoromethylphenyl diazirine bifunctional linker (TPD-clip). The amount of TagF6 grafted on PEG-yne was calculated by NMR using an internal standard (trifluoroethanol) and adjusting of the acquisition and processing parameters. NMR is used as a valuable alternative to the complex procedures often employed for the quantification of functionalities on biomaterials. The accuracy of the qNMR methodology was attested by controlling its linearity, the determination of limits of quantification and the percentage of recovery. A good assessment of the TagF6 grafting rates was obtained after taking into account the inherent unspecific adsorption that occurs on materials. This versatile methodology that combines simple chemistry and a common analytical tool was, in a second time, applied to the preparation of a PEG conjugated with a RGD (Arg-Gly-Asp) peptidomimetic in a controlled manner. [less ▲]

Implant comprising a core and a tube encasing the core

Patent (2012)

The present invention relates to an implant comprising: - a core material comprising polydimethylsiloxane or at least one hydrogel polymer; - a tube encasing said core material comprising an ethylene ... [more ▼]

The present invention relates to an implant comprising: - a core material comprising polydimethylsiloxane or at least one hydrogel polymer; - a tube encasing said core material comprising an ethylene vinyl acetate polymer or at least one hydrogel polymer; - a sealant for closure of the open ends of said tube comprising polydimethylsiloxane or a mono-, di-, or triacetoxy derivative thereof, or at least one hydrogel polymer; and - at least one active ingredient; wherein said at least one active ingredient is selected from the group comprising celecoxib, sulindac, tamoxifen, oestrogen, oestradiol, ethinyl oestradiol, mestranol, dienogest, norgestrel, levonorgestrel, desogestrel, norgestimate, ethynodiol diacetate, leuprorelin, buserelin, gonrelin, triptorelin, nafarelin, deslorelin, histrelin, and supprelin; and with the proviso that when the sealant is said at least one hydrogelpolymer, the core material comprises polydimethylsiloxane. Furthermore, the invention relates to an implant for use as a medicament. In particular, the invention relates to an implant for use in the treatment of endometriosis. [less ▲]

Synthetic and mechanistic inputs of photochemistry into the bisacetylacetonatocobalt- mediated radical polymerization of n-butyl acrylate and vinyl acetate

in Polymer Chemistry (2012), 3(7), 1856-1866

The input of photochemistry to the Co(acac)2 mediated radical polymerization (CMRP) of n-butyl acrylate and vinyl acetate is investigated for the first time. Upon UV irradiation, photoinitiators are able ... [more ▼]

The input of photochemistry to the Co(acac)2 mediated radical polymerization (CMRP) of n-butyl acrylate and vinyl acetate is investigated for the first time. Upon UV irradiation, photoinitiators are able to initiate the n-butyl acrylate polymerization that remains controlled up to very high molar masses (>4 × 106 g mol−1) with low polydispersities. The photoinitiator as well as the irradiation time must be appropriately chosen to reach acceptable initiator efficiencies while maintaining an optimal control over the polymerization. Laser flash photolysis experiments were then carried out to evidence the addition of alkyl and phosphonyl radicals onto Co(acac)2 and to determine the rate constants (kdeact) of these addition reactions that were still lacking. Finally, both kinetics of polymerization and spin-trapping experiments have evidenced that the C–Co bond at the extremity of the dormant polymer chains can be easily photocleaved. UV irradiation can therefore be considered as an additional lever for tuning the reactivity of the CMRP process mediated by Co(acac)2. [less ▲]

Controlled radical polymerization of halogenated monomers

Patent (2012)

Process for the preparation of a halogenated polymer comprising a controlled radical polymerization step of at least one monomer containing at least one halogen-carbon bond performed in the presence of an ... [more ▼]

Process for the preparation of a halogenated polymer comprising a controlled radical polymerization step of at least one monomer containing at least one halogen-carbon bond performed in the presence of an organo-cobalt complex, said polymerization step being further carried out in the presence of at least one ligand. [less ▲]