LECLERCQ Laurent
Thème de Recherche: Organisation Biomoléculaire
laurent.leclercq
umontpellier.fr
0448792195
Bureau: N3J16, Etg: 3 - Site : Pôle Chimie Balard Recherche
Domaines de Recherche: - Chimie/ou physique
- Chimie/Chimie organique
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Dernieres productions scientifiques :
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Interactions between Oppositely Charged Polyelectrolytes by Isothermal Titration Calorimetry: Effect of Ionic Strength and Charge Density
Auteur(s): Lounis F., Chamieh J., Leclercq L., Gonzales Philippe, Geneste Amine, Prelot Benedicte, Cottet H.
(Article) Publié:
Journal Of Physical Chemistry B, vol. 121 p.2684-2694 (2017)
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Correlation of Length of Linear Oligo(ethanamino) Amides with Gene Transfer and Cytotoxicity.
Auteur(s): Scholz Claudia, Kos Petra, Leclercq L., Jin X., Cottet H., Wagner Ernest
(Article) Publié:
Chemmedchem, vol. 9 p.2104-2110 (2014)
Ref HAL: hal-01069014_v1
DOI: 10.1002/cmdc.201300483
Résumé: The optimization of synthetic carriers for gene transfer remains a major challenge. Cationic polymers such as polyethylenimine (PEI) often show increasing gene transfer activity with increasing molecular weight, but this favorable effect is accompanied by an undesired increase in cytotoxicity. Moreover, the polydispersity of polymers prevents accurate determination of optimum size. Herein we describe the step-by-step elongation of precise linear oligo(ethanamino) amides by making use of the artificial amino acid succinoyl-tetraethylene pentamine (Stp) for solid-phase-assisted synthesis. This procedure enabled us to identify the optimal oligomer Stp30-W (8.4 kDa) with a length of 30 Stp units, with which effective gene transfer occurs in the absence of cytotoxicity. The transfection efficiency of Stp30-W exceeded that of standard linear PEI (22 kDa) by sixfold; nevertheless, Stp30-W exhibited tenfold lower cytotoxicity. In addition to the lower molecular weight, the succinate spacer between the oligoamine units may also contribute to the favorable biocompatibility. The cytotoxicity of the cationic polymer PEI is a major concern for use as a carrier for gene delivery, so this comparison between linear PEI and the new Stp oligomers is particularly relevant.
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Experimental and Theoretical Studies of Polyanion−Polycation Complexation in Salted Media in the Context of Nonviral Gene Transfection.
Auteur(s): Boustta M., Leclercq L., Vert M., Vasilevskaya Valentina V.
(Article) Publié:
Macromolecules, vol. 47 p.3574-3581 (2014)
Ref HAL: hal-01010383_v1
DOI: 10.1021/ma500447k
Résumé: Positively and negatively charged molecules, endothelia, and cells play important roles in biological salted aqueous media. This work aimed at studying artificial polyelectrolyte complexes in terms of formation and stability in the context of the increasing interest for the use of polyelectrolyte systems in drug delivery or as polyelectrolyte complexes or polyplexes for gene transfection. The effect of salt concentration on model polyelectrolyte complexes was studied both experimentally and from a theoretical viewpoint. The critical salt concentration at which phase separation appeared when multifunctional polyanions, namely poly(Llysine citramide) and poly(L-lysine citramide imide) were mixed with poly(L-lysine) showed that salt concentration, degree of polymerization and charge density conditioned the formation and the stability of corresponding polyelectrolyte complexes. Data agreed well with the trends indicated by the theoretical approach and they are discussed in comparison with the case of nonviral transfection using polyplexes.
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Build-up of an antimicrobial multilayer coating on a textile support based on a methylene blue-poly(cyclodextrin) complex.
Auteur(s): Martin A., Tabary Nicolas, Chai Feng, Leclercq L., Junthip Jatupol, Aubert-Viard François, Neut Christel, Weltrowski Marek, Blanchemain Nicolas, Martel Bernard
(Article) Publié:
Biomedical Materials, vol. 8 p.065006 (2013)
Ref HAL: hal-01004022_v1
DOI: 10.1088/1748-6041/8/6/065006
Résumé: The aim of this work was to develop an antibacterial multilayer coating activated with methylene blue (MB) and based on chitosan (CHT) and cyclodextrin polyelectrolyte (polyCD) onto a non-woven polyethylene terephthalate (PET) textile support. The MB-free and MB-loaded systems were built-up by applying the dip-coating technique, alternating soak cycles of the PET textile preliminarily modified with carboxylate groups in CHT and in polyCD or polyCD/MB complex solutions. The layer-by-layer assembly build-up was followed by optical waveguide lightmode spectroscopy on the one hand and by gravimetry once it was applied on the textile substrate on the other hand. Two chitosan grades were used, low molecular weight (CHT-L) and medium molecular weight (CHT-M). The influence of the molar ratio CD/MB in the polyCD solutions was varied and finally the system underwent a post reticulation with genipin. Such parameters influences were investigated with regard to the loading capacity in MB of the systems, the release kinetics profiles of MB in pure water, phosphate buffer and MEM media, and the degradation of the self-assembled coating in the same media. Finally, biological and microbiological tests were performed to demonstrate the cytocompatibility of the systems and their ability to display a sustained antibacterial effect of the device through the MB prolonged release.
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Multilayered textile coating based on a -cyclodextrin polyelectrolyte for the controlled release of drugs.
Auteur(s): Martin A., Tabary Nicolas, Leclercq L., Junthip Jatupol, Degoutin Stéphanie, Aubert-Viard François, Cazaux Fréderic, Lyskawa Joël, Janus Ludovic, Briac Marc, Martel Bernard
(Article) Publié:
Carbohydrate Polymers, vol. 93 p.718-730 (2013)
Ref HAL: hal-01003157_v1
DOI: 10.1016/j.carbpol.2012.12.055
Résumé: The aim of this work was to develop the formation of multilayered coating incorporating a cyclodextrin polyelectrolyte onto a non-woven polyethylene terephthalate (PET) textile support in order to obtain reservoir and sustained release properties towards bioactive molecules. We optimized the multilayer assembly immobilization onto the PET surface according to the layer-by-layer (LbL) deposition process. After a pre-treatment of the textile support aiming to offer a sufficient ionic character to the surface, it was alternatively immersed into two polyelectrolytes aqueous solutions consisting of chitosan (CHT) as polycation on the one hand, and a _-cyclodextrin polymer (polyCTR- _CD) as polyanion on the other hand. In a second approach, a TBBA/polyCTR- _CD complex (4-tert-butylbenzoic acid, TBBA) was used in order to load the system with a drug model whose kinetics of release was assessed. Gravimetry, microscopy, OWLS, colorimetric titration, infrared and zetametry were used as characterization techniques. An effective deposition on the textile surface due to ionic interactions with alternation of up to 10 layers of each of both polyelectrolytes was clearly evidenced. However, we observed that layer formation occurred to a lesser extent when TBBA/polyCTR- _CD complex was applied instead of polyCTR- _CD alone. The release study showed that drug reservoir properties and release kinetics could be controlled by the number of layers in the system and that TBBA release was faster than the multilayered coating degradation.
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