Self assemblies of amphiphilic cyclodextrins

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Lipid Lateral Segregation driven by Diacyl Cyclodextrin Interactions at the Membrane Surface

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Solvent-free chemo-enzymatic synthesis of fatty acyl-β-cyclodextrin

International audienceLipase-catalyzed transesterifications were carried out without solvent and in mild conditions on permethylated β-cyclodextrins derivatives to obtain lipidyl-cyclodextrin, a new class of amphiphilic compounds with expected auto-assembly properties. Good conversion rate, of 6I-(N-hydroxyethylsuccinamido)-6I-deoxy-2I, 3I-di-O-methyl-hexakis (2II–VII,3II–VII,6II–VII-tri-O-methyl) cyclomaltoheptaose were obtained by using lipozyme as catalyst. Critical Aggregation Concentrations of these new derivatives of amphiphilic cyclodextrins (5.10−3 and 5.10−4 M) are in favor of an auto-association behavior. Finally, NMR experiments were carried out to evaluate the self-assembly of the compounds in water. The resulting supramolecular aggregates have potential to be used as nano-carriers for drug

Enzymatic catalysis in presence of cyclodextrins

International audienceCyclodextrins are able to interact in biocatalysis reaction. Their effects as solubilizing agents, inhibitor blocking agents and chiral selectors are well documented and they also interact before the enzyme-catalyzed reaction. Indeed, they have lyo-protectant effect for enzyme in organic medium biocatalysis and they participate in the refolding of inactive enzymes to regain their active form

Dimerization of xanthene dyes in water: Experimental studies and molecular dynamic simulations

1-D and 2-D NMR experiments and molecular dynamics simulations have been performed to study the dimerization process of two laser dyes namely Rodamine 6G and Pyronine 6G in water. Two possible stacked dimer structures have been evidenced, and the agreement between experimental and theoretical results is very good. The role of dispersive and electrostatic forces in the dimerization mechanism is discussed. This analysis allows us to suggest some chemical modifications on xanthene dyes to prevent such dimerization. On this basis, a new synthesized rhodamine is described which does not exhibit any dimerization phenomenon in a large range of concentrations

Functionalized cyclodextrins as biomimetic materials to degrade nerve agents

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Functionalized cyclodextrins as biomimetic materials to degrade nerve agents

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Positive variation of the MRI signal via intramolecular inclusion complexation of a C-2 functionalized β-cyclodextrin

International audienceThe synthesis of a new contrast agent based on a β-cyclodextrin scaffold and bearing a flexible lipophilic spacer arm on its secondary face is reported. Intermolecular host–guest inclusion complexes were known to undergo an enhancement of the contrast imaging. We extend this concept to intramolecular complexation. Inter- and intramolecular interactions are compared by NMR spectroscopy, circular dichroism and magnetic resonance imaging using hydrocinnamic acid and adamantane carboxylic acid as external guests. This positive variation of the observed relaxivity is a key element of new strategies aiming at developing smart molecular MRI probes

An air-stable lithiated cathode material based on a 1,4-benzenedisulfonate backbone for organic Li-ion batteries

International audienceTo meet current market demands as well as emerging environmental concerns there is a need to develop less polluting battery technologies

Direct investigation of the vectorization properties of amphiphilic cyclodextrins in phospholipid films

URL: http://www-spht.cea.fr/articles/s01/005International audiencePhospholipids form very stable Newton Black Films which have some similar properties of real biological membrane. Recently, new cyclodextrin derivatives have been synthesised and were shown to exhibit strong amphiphilic properties. In this paper, we simulate the action on phospholipids of these new amphiphilic cyclodextrins. Mixed phospholipids/cyclodextrin derivatives films were prepared and studied using X-ray reflectivity for various phospholipids/ cyclodextrins ratios. A molar ratio of 3 affords a highly stable film for which the molecular structure has been investigated in details. The cyclodextrin molecular carrier property is also addressed through the addition of a neuroleptic drug: Dosulepin, to this complex film architecture, as an example of potential application