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Peters R.J.R.W.,Radboud University Nijmegen | Marguet M.,CNRS Organic Polymer Chemistry Laboratory | Marais S.,University of Bordeaux Segalen | Fraaije M.W.,University of Groningen | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2014

Enzyme-filled polystyrene-b-poly(3-(isocyano-L-alanyl-aminoethyl)thiophene) (PS-b-PIAT) nanoreactors are encapsulated together with free enzymes and substrates in a larger polybutadiene-b-poly(ethylene oxide) (PB-b-PEO) polymersome, forming a multicompartmentalized structure, which shows structural resemblance to the cell and its organelles. An original cofactor-dependent three-enzyme cascade reaction is performed, using either compatible or incompatible enzymes, which takes place across multiple compartments. Mimicking cells: Enzyme-filled polystyrene-b-poly(3-(isocyano-L-alanylaminoethyl) thiophene) (PS-b-PIAT) nanoreactors have been encapsulated together with free enzymes and substrates in a larger polymersome to form a multicompartmentalized structure, which shows structural resemblance to a cell and its organelles (see picture). An original cofactor-dependent three-enzyme cascade reaction, with either compatible or incompatible enzymes, takes place across multiple compartments. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Vuong Q.L.,University of Mons | Berret J.-F.,University Paris Diderot | Fresnais J.,CNRS Analytical Sciences Lab | Gossuin Y.,University of Mons | Sandre O.,CNRS Organic Polymer Chemistry Laboratory
Advanced Healthcare Materials | Year: 2012

Magnetic particles are very efficient magnetic resonance imaging (MRI) contrast agents. In recent years, chemists have unleashed their imagination to design multi-functional nanoprobes for biomedical applications including MRI contrast enhancement. This study is focused on the direct relationship between the size and magnetization of the particles and their nuclear magnetic resonance relaxation properties, which condition their efficiency. Experimental relaxation results with maghemite particles exhibiting a wide range of sizes and magnetizations are compared to previously published data and to wellestablished relaxation theories with a good agreement. This allows deriving the experimental master curve of the transverse relaxivity versus particle size and to predict the MRI contrast efficiency of any type of magnetic nanoparticles. This prediction only requires the knowledge of the size of the particles impermeable to water protons and the saturation magnetization of the corresponding volume. To predict the T2 relaxation efficiency of magnetic single crystals, the crystal size and magnetization - obtained through a single Langevin fit of a magnetization curve - is the only information needed. For contrast agents made of several magnetic cores assembled into various geometries (dilute fractal aggregates, dense spherical clusters, core-shell micelles, hollow vesicles...), one needs to know a third parameter, namely the intra-aggregate volume fraction occupied by the magnetic materials relatively to the whole (hydrodynamic) sphere. Finally a calculation of the maximum achievable relaxation effect - and the size needed to reach this maximum - is performed for different cases: maghemite single crystals and dense clusters, core-shell particles (oxide layer around a metallic core) and zinc-manganese ferrite crystals. © 2012 WILEY-VCH Verlag GmbH & Co.KGaA, Weinheim.


Dakshinamoorthy D.,CNRS Organic Polymer Chemistry Laboratory | Peruch F.,CNRS Organic Polymer Chemistry Laboratory
Journal of Polymer Science, Part A: Polymer Chemistry | Year: 2012

A series of di- and triblock copolymers [poly(L-lactide-b-μ- caprolactone), poly(D,L-lactide-b-μ-caprolactone), poly(μ-caprolactone-b- L-lactide), and poly(μ-caprolactone-b-L-lactide-b-μ-caprolactone)] have been synthesized successfully by sequential ring-opening polymerization of μ-caprolactone (μ-CL) and lactide (LA) either by initiating PCL block growth with living PLA chain end or vice versa using titanium complexes supported by aminodiol ligands as initiators. Poly(trimethylene carbonate-b-μ-caprolactone) was also prepared. A series of random copolymers with different comonomer composition were also synthesized in solution and bulk of μ-CL and D,L-lactide. The chemical composition and microstructure of the copolymers suggest a random distribution with short average sequence length of both the LA and μ-CL. Transesterification reactions played a key role in the redistribution of monomer sequence and the chain microstructures. Differential scanning calorimetry analysis of the copolymer also evidenced the random structure of the copolymer with a unique T g. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 A series of di- and triblock copolymers of μ-caprolactone, L-lactide, D,L-lactide, and trimethylene carbonate have been synthesized successfully by sequential ring-opening polymerization technique using titanium complexes supported by aminodiol ligands as initiators. It was shown that either μ-caprolactone or lactide could be polymerized first. Copolymers of μ-caprolactone and lactides with different composition were also synthesized both in solution and bulk conditions, revealing that transesterification reactions could play a significant role in the redistribution of monomer leading to random copolymers. Copyright © 2012 Wiley Periodicals, Inc.


Tingaut P.,Empa - Swiss Federal Laboratories for Materials Science and Technology | Zimmermann T.,Empa - Swiss Federal Laboratories for Materials Science and Technology | Sebe G.,CNRS Organic Polymer Chemistry Laboratory
Journal of Materials Chemistry | Year: 2012

In this article, we highlight the potential of nanocelluloses, such as cellulose nanocrystals (CNC) and microfibrillated cellulose (MFC), to serve as building blocks for the design of hierarchical functional nanomaterials. Four categories of value-added nanomaterials are envisaged here, namely aerogels, emulsions, templated materials and stimuli-responsive nanodevices. But most importantly, we demonstrate that appropriate functionalization methods are required in order to tailor the nanocellulose surface and further design materials with required characteristics. © 2012 The Royal Society of Chemistry.


Maisonneuve L.,CNRS Organic Polymer Chemistry Laboratory | Lamarzelle O.,CNRS Organic Polymer Chemistry Laboratory | Rix E.,CNRS Organic Polymer Chemistry Laboratory | Grau E.,CNRS Organic Polymer Chemistry Laboratory | Cramail H.,CNRS Organic Polymer Chemistry Laboratory
Chemical Reviews | Year: 2015

An overview of the main synthetic routes to polyurethanes (PU) according to their dependence on phosgene and isocyanate is presented. The rearrangement of acyl azide followed by its polycondensation with alcohol functions represents another route to access polyurethane, through an in situ isocyanate formation during polymerization. The PUs obtained by polycondensation, have similar structures as those produced by the polyaddition of polyisocyanates and polyols.


Thevenot J.,CNRS Organic Polymer Chemistry Laboratory | Oliveira H.,CNRS Organic Polymer Chemistry Laboratory | Sandre O.,CNRS Organic Polymer Chemistry Laboratory | Lecommandoux S.,CNRS Organic Polymer Chemistry Laboratory
Chemical Society Reviews | Year: 2013

Magnetic responsive materials are the topic of intense research due to their potential breakthrough applications in the biomedical, coatings, microfluidics and microelectronics fields. By merging magnetic and polymer materials one can obtain composites with exceptional magnetic responsive features. Magnetic actuation provides unique capabilities as it can be spatially and temporally controlled, and can additionally be operated externally to the system, providing a non-invasive approach to remote control. We identified three classes of magnetic responsive composite materials, according to their activation mode and intended applications, which can be defined by the following aspects. (A) Their ability to be deformed (stretching, bending, rotation) upon exposure to a magnetic field. (B) The possibility of remotely dragging them to a targeted area, called magnetic guidance, which is particularly interesting for biomedical applications, including cell and biomolecule guidance and separation. (C) The opportunity to use magnetic induction for thermoresponsive polymer materials actuation, which has shown promising results for controlled drug release and shape memory devices. For each category, essential design parameters that allow fine-tuning of the properties of these magnetic responsive composites are presented using key examples. © 2013 The Royal Society of Chemistry.


Marguet M.,CNRS Organic Polymer Chemistry Laboratory | Bonduelle C.,CNRS Organic Polymer Chemistry Laboratory | Lecommandoux S.,CNRS Organic Polymer Chemistry Laboratory
Chemical Society Reviews | Year: 2013

The cell is certainly one of the most complex and exciting systems in Nature that scientists are still trying to fully understand. Such a challenge pushes material scientists to seek to reproduce its perfection by building biomimetic materials with high-added value and previously unmatched properties. Thanks to their versatility, their robustness and the current state of polymer chemistry science, we believe polymer-based materials to constitute or represent ideal candidates when addressing the challenge of biomimicry, which defines the focus of this review. The first step consists in mimicking the structure of the cell: its inner compartments, the organelles, with a multicompartmentalized structure, and the rest, i.e. the cytoplasm minus the organelles (mainly cytoskeleton/cytosol) with gels or particular solutions (highly concentrated for example) in one compartment, and finally the combination of both. Achieving this first structural step enables us to considerably widen the gap of possibilities in drug delivery systems. Another powerful property of the cell lies in its metabolic function. The second step is therefore to achieve enzymatic reactions in a compartment, as occurs in the organelles, in a highly controlled, selective and efficient manner. We classify the most exciting polymersome nanoreactors reported in our opinion into two different subsections, depending on their very final concept or purpose of design. We also highlight in a thorough table the experimental sections crucial to such work. Finally, after achieving control over these prerequisites, scientists are able to combine them and push the frontiers of biomimicry further: from cell structure mimics towards a controlled biofunctionality. Such a biomimetic approach in material design and the future research it will stimulate, are believed to bring considerable enrichments to the fields of drug delivery, (bio)sensors, (bio)catalysis and (bio)technology. © The Royal Society of Chemistry 2013.


Fevre M.,CNRS Organic Polymer Chemistry Laboratory | Pinaud J.,CNRS Organic Polymer Chemistry Laboratory | Gnanou Y.,CNRS Organic Polymer Chemistry Laboratory | Vignolle J.,CNRS Organic Polymer Chemistry Laboratory | Taton D.,CNRS Organic Polymer Chemistry Laboratory
Chemical Society Reviews | Year: 2013

The chemistry of N-heterocyclic carbenes (NHCs) has witnessed tremendous development in the past two decades: NHCs have not only become versatile ligands for transition metals, but have also emerged as powerful organic catalysts in molecular chemistry and, more recently, in metal-free polymer synthesis. To understand the success of NHCs, this review first presents the electronic properties of NHCs, their main synthetic methods, their handling, and their reactivity. Their ability to activate key functional groups (e.g. aldehydes, esters, heterocycles, silyl ketene acetals, alcohols) is then discussed in the context of molecular chemistry. Focus has been placed on the activation of substrates finding analogies with monomers (e.g. bis-aldehydes, multi-isocyanates, cyclic esters, epoxides, N-carboxyanhydrides, etc.) and/or initiators (e.g. hydroxy- or trimethylsilyl-containing reagents) employed in such "organopolymerisation" reactions utilizing NHCs. A variety of metal-free polymers, including aliphatic polyesters and polyethers, poly(α-peptoid)s, poly(meth)acrylates, polyurethanes, or polysiloxanes can be obtained in this way. The last section covers the use of NHCs as structural components of the polymer chain. Indeed, NHC-based photoinitiators, chain transfer agents or functionalizing agents, as well as bifunctional NHC monomer substrates, can also serve for metal-free polymer synthesis. This journal is © The Royal Society of Chemistry.


Garanger E.,CNRS Organic Polymer Chemistry Laboratory | Lecommandoux S.,French National Center for Scientific Research
Angewandte Chemie - International Edition | Year: 2012

Interdisciplinary: The application of protein-engineering techniques to polymer materials can lead to the design and preparation of biocompatible, biodegradable, stimuli-sensitive copolymers bearing biologically responsive peptide motifs (see picture). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Schappacher M.,CNRS Organic Polymer Chemistry Laboratory | Deffieux A.,CNRS Organic Polymer Chemistry Laboratory
Journal of the American Chemical Society | Year: 2011

A route to macrocyclic polymers based on a new unimolecular ring-closure process has been investigated. It involves the direct end-to-end coupling of an α,ω-bis[chloroiron(III) meso-tetraphenylporphyrin] telechelic linear polystyrene synthesized by living polymerization followed by chain-end functionalization. The corresponding macrocyclic polystyrene was obtained readily and selectively by intramolecular condensation of the α,ω-bis[chloroiron(III) meso-tetraphenylporphyrin] polymer ends in the presence of a base to yield a diiron(III)-μ-oxobis(porphyrin) dimer as ring-closing unit. Addition of dilute HCl was shown to rapidly reconvert the diiron(III)-μ-oxobis(porphyrin) unit into the initial bis[chloroiron(III) porphyrin], demonstrating the selectivity and complete reversibility of the cyclization process. The synthesis and detailed structural characterization of the α,ω-homodifunctional precursor and the corresponding macrocyclic polystyrene along with an analysis of the porphyrin dimerization reaction using NMR spectroscopy and size-exclusion chromatography coupled with a diode array detector are presented. © 2011 American Chemical Society.

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