Audrey Tourrette - Academia.edu (original) (raw)

Papers by Audrey Tourrette

OATAO is an open access repository that collects the work of Toulouse researchers and makes it fr... more OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. This is an author-deposited version published in : http://oatao.univ-toulouse.fr/ Eprints ID : 14233

The aim of this study was to elaborate a stable dispersion of organogel nanoparticles in water. O... more The aim of this study was to elaborate a stable dispersion of organogel nanoparticles in water. Organogels are soft materials, which result from the immobilisation of an organic liquid in a three-dimensional network by a gelator. The organogels in this study were obtained from an organic oil and a low molecular-mass organic gelator or LMOG. These organogels are usually prepared by dissolving the gelator in an oil at high temperature and then cooling the solution below its characteristic sol-gel transition temperature or Tgel. In the present study, the formulation and characterisation of electrostatically stabilised gelled oil nanoparticles will be described. Thus, an organogel made of soybean oil gelled with 12-hydroxystearic acid or HSA, was emulsified into an aqueous solution containing a branched polycation, polyethyleneimine or PEI, to form stable nanoparticles of gelled oil after cooling at room temperature. The loading of oil gelled nanoparticules with a hydrophobic model mole...

Journal of Colloid and Interface Science, 2015

The chemical interaction between DNA macromolecules and hard tissues in vertebrate is of foremost... more The chemical interaction between DNA macromolecules and hard tissues in vertebrate is of foremost importance in paleogenetics, as bones and teeth represent a major substrate for the genetic material after cell death. Recently, the empirical hypothesis of DNA "protection" over time thanks to its adsorption on hard tissues was revisited from a physico-chemical viewpoint. In particular, the existence of a strong interaction between phosphate groups of DNA backbone and the surface of apatite nanocrystals (mimicking bone/dentin mineral) was evidenced on an experimental basis. In the field of nanomedicine, DNA or RNA can be used for gene transport into cells, and apatite nanocarriers then appear promising. In order to shed some more light on interactions between DNA molecules and apatite, the present study focuses on the adsorption of a "model" nucleotide, cytidine 5' monophosphate (CMP), on a carbonated biomimetic apatite sample. The follow-up of CMP kinetics of adsorption pointed out the rapidity of interaction with stabilization reached within few minutes. The adsorption isotherm could be realistically fitted to the Sips model (Langmuir-Freundlich) suggesting the influence of surface heterogeneities and adsorption cooperativity in the adsorption process. The desorption study pointed out the reversible character of CMP adsorption on biomimetic apatite. This contribution is intended to prove helpful in view of better apprehending the molecular interaction of DNA fragments and apatite compounds, independently of the application domain, such as bone diagenesis or nanomedicine. This study may also appear informative for researchers interested in the origins of life on Earth and the occurrence and behavior of primitive biomolecules.

The Journal of Physical Chemistry B, 2010

Three different types of photoluminescent hybrid materials containing trivalent lanthanide (Ln 3+... more Three different types of photoluminescent hybrid materials containing trivalent lanthanide (Ln 3+ ) Eu 3+ , Tb 3+ ) ions, chitosan, and silica have been prepared with different structural features. The different silica sources lead to diverse microstructures of hybrid materials, with silica being homogeneously dispersed in the chitosan materials (LnChS-H), or forming a core-shell morphology. Postsynthesis treatment is necessary for embedding the luminescent probe. The Ln 3+ -based materials have been investigated by photoluminescence spectroscopy (12-300 K). The chitosan-Eu 3+ -related local environment is maintained in the EuChS-H hybrid material. The emission features of the core-shell materials are characterized by the presence of two Eu 3+ distinct local environments, one associated with the chitosan core and the other with the silica shell.

Microporous and Mesoporous Materials, 2007

Mixed-micelles of long-chain phosphatidylcholine and surfactants are of considerable scientific a... more Mixed-micelles of long-chain phosphatidylcholine and surfactants are of considerable scientific and biomedical interest. Lecithins are natural phospholipids from egg or soybean. Lecithin/dodecylamine mixed-micelles in an alcoholic/aqueous media allow to template the formation of sponge mesoporous silica (SMS) materials through a self-assembly process between mixed-micelles and tetraethoxysilane (TEOS). SMS synthesis adds a porosity control to the classical sol-gel synthesis used for enzymes encapsulation. We are reporting here the key parameters of SMS synthesis procedure (amount of amine, TEOS, ethanol, water, lecithin nature, salt addition, etc.), as well as a fine description of SMS structure by TEM. SMS features an isotropic 3-dimensional (3-D) pore structure similarly to SBA-16, but with a lower degree of mesoscopic structural order. Its porosity results from cavities and connecting channels, whose length is controlled by the synthesis conditions. Cavity diameters can reach 4.7 nm in accordance to the lecithin maximum alkyl chain length. Surface areas range from 300 to 800 m 2 /g, and pore volumes from 0.30 to 0.85 mL/g. The use of lactose as an enzyme stabilizing agent does not change the pore structure of SMS. A very fragile enzyme, alcohol dehydrogenase, has been successfully encapsulated by this way, providing the first example of successful entrapment of this enzyme in an inorganic matrix. SMS encapsulation procedure is biomolecules friendly and opens a bright perspective for biomolecules processing for biocatalysis, biosensors or biofuel cell applications.

Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2009

... The second peak at 286.7 eV corresponds to C OH, C O and C N (alcohol, ether, amine) carbon b... more ... The second peak at 286.7 eV corresponds to C OH, C O and C N (alcohol, ether, amine) carbon bond (C2). The third peak at 288.6 eV is indicative of the O C O and C O (double ether, carbonyl) carbon bond (C3). ... C C or C H, C OH, C O or C N, O C O, O C N. ...

Chemistry of Materials, 2005

... Audrey Tourrette, Giuseppe Sparapano, Karine Molvinger, Jean-Marie Devoisselle, Corine Gérard... more ... Audrey Tourrette, Giuseppe Sparapano, Karine Molvinger, Jean-Marie Devoisselle, Corine Gérardin, and Françoise Quignard. ... Hirai, A.; Odani, H.; Nakajima, A. Polym. Bull. 1991, 26, 17. [CrossRef]. (26) Martinsen, A.; Storrø, I.; Skjåk-Bræk. G. Biotechnol. Bioeng.1992, 39, 186. ...

Carbohydrate Polymers, 2010

An innovative strategy for functional finishing of textile materials is based on the incorporatio... more An innovative strategy for functional finishing of textile materials is based on the incorporation of a thin layer of surface modifying systems (SMS) in the form of stimuli-sensitive microgels or hydrogels. Since the copolymerization of poly(N-isopropylacrylamide) with an ionizable polymer, such as chitosan, results in a microgel that is responsive to both temperature and pH, the microparticulate hydrogel of poly-NiPAAmchitosan copolymer (PNCS) was synthesized using surfactant-free emulsion method. The microparticle size in dry (collapsed) state is estimated at 200 nm by SEM and TEM, and effect of temperature and pH on microparticles was investigated by DLS and UV-vis spectrophotometry. The incorporation of PNCS microparticles to cotton material was done by a simple pad-dry-cure procedure from aqueous microparticle dispersion that contained 1,2,3,4-butanetetracarboxylic acid (BTCA) as a crosslinking agent. This application method provided sufficient integrity to coating by maintaining the responsiveness of surface modifying system. The stimuli-responsiveness of modified cotton fabric has been confirmed in terms of regulating its water uptake in dependence of pH and temperature.

Carbohydrate Polymers, 2011

... adsorption increases with the polarity of the surface groups of the polymer, in the order chi... more ... adsorption increases with the polarity of the surface groups of the polymer, in the order chitin < agar ≤ chitosan < carrageenan < alginic acid alginate. The surface area and the mesopore distribution of the aerogels depend both on the dispersion of the parent hydrogel and on ...

Journal of Colloid and Interface Science, 2006

The impregnation of a carrageenan gel by a silica sol is an efficient method to form a composite ... more The impregnation of a carrageenan gel by a silica sol is an efficient method to form a composite material which can be conveniently activated by CO2 supercritical drying. The textural properties of the solids have been characterized by nitrogen adsorption-desorption at 77 K and their composition by thermogravimetric analysis and EDX microprobe. Morphology was examined by SEM. The silica-carrageenan composites present an open macroporous structure. Silica particles retained inside the gel behaved as pillars between the polysaccharide fibrils and form a stick-and-ball network. The stiffening of the carrageenan gel by silica prevented its shrinkage upon drying. The nature of the alkali cations affected the retention of silica particles inside the gel. In the absence of silica, carrageenan fibrils rearrange under supercritical drying and form an aerogel with cavities in the mesopore range.

OATAO is an open access repository that collects the work of Toulouse researchers and makes it fr... more OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. This is an author-deposited version published in : http://oatao.univ-toulouse.fr/ Eprints ID : 14233

The aim of this study was to elaborate a stable dispersion of organogel nanoparticles in water. O... more The aim of this study was to elaborate a stable dispersion of organogel nanoparticles in water. Organogels are soft materials, which result from the immobilisation of an organic liquid in a three-dimensional network by a gelator. The organogels in this study were obtained from an organic oil and a low molecular-mass organic gelator or LMOG. These organogels are usually prepared by dissolving the gelator in an oil at high temperature and then cooling the solution below its characteristic sol-gel transition temperature or Tgel. In the present study, the formulation and characterisation of electrostatically stabilised gelled oil nanoparticles will be described. Thus, an organogel made of soybean oil gelled with 12-hydroxystearic acid or HSA, was emulsified into an aqueous solution containing a branched polycation, polyethyleneimine or PEI, to form stable nanoparticles of gelled oil after cooling at room temperature. The loading of oil gelled nanoparticules with a hydrophobic model mole...

Journal of Colloid and Interface Science, 2015

The chemical interaction between DNA macromolecules and hard tissues in vertebrate is of foremost... more The chemical interaction between DNA macromolecules and hard tissues in vertebrate is of foremost importance in paleogenetics, as bones and teeth represent a major substrate for the genetic material after cell death. Recently, the empirical hypothesis of DNA "protection" over time thanks to its adsorption on hard tissues was revisited from a physico-chemical viewpoint. In particular, the existence of a strong interaction between phosphate groups of DNA backbone and the surface of apatite nanocrystals (mimicking bone/dentin mineral) was evidenced on an experimental basis. In the field of nanomedicine, DNA or RNA can be used for gene transport into cells, and apatite nanocarriers then appear promising. In order to shed some more light on interactions between DNA molecules and apatite, the present study focuses on the adsorption of a "model" nucleotide, cytidine 5' monophosphate (CMP), on a carbonated biomimetic apatite sample. The follow-up of CMP kinetics of adsorption pointed out the rapidity of interaction with stabilization reached within few minutes. The adsorption isotherm could be realistically fitted to the Sips model (Langmuir-Freundlich) suggesting the influence of surface heterogeneities and adsorption cooperativity in the adsorption process. The desorption study pointed out the reversible character of CMP adsorption on biomimetic apatite. This contribution is intended to prove helpful in view of better apprehending the molecular interaction of DNA fragments and apatite compounds, independently of the application domain, such as bone diagenesis or nanomedicine. This study may also appear informative for researchers interested in the origins of life on Earth and the occurrence and behavior of primitive biomolecules.

The Journal of Physical Chemistry B, 2010

Three different types of photoluminescent hybrid materials containing trivalent lanthanide (Ln 3+... more Three different types of photoluminescent hybrid materials containing trivalent lanthanide (Ln 3+ ) Eu 3+ , Tb 3+ ) ions, chitosan, and silica have been prepared with different structural features. The different silica sources lead to diverse microstructures of hybrid materials, with silica being homogeneously dispersed in the chitosan materials (LnChS-H), or forming a core-shell morphology. Postsynthesis treatment is necessary for embedding the luminescent probe. The Ln 3+ -based materials have been investigated by photoluminescence spectroscopy (12-300 K). The chitosan-Eu 3+ -related local environment is maintained in the EuChS-H hybrid material. The emission features of the core-shell materials are characterized by the presence of two Eu 3+ distinct local environments, one associated with the chitosan core and the other with the silica shell.

Microporous and Mesoporous Materials, 2007

Mixed-micelles of long-chain phosphatidylcholine and surfactants are of considerable scientific a... more Mixed-micelles of long-chain phosphatidylcholine and surfactants are of considerable scientific and biomedical interest. Lecithins are natural phospholipids from egg or soybean. Lecithin/dodecylamine mixed-micelles in an alcoholic/aqueous media allow to template the formation of sponge mesoporous silica (SMS) materials through a self-assembly process between mixed-micelles and tetraethoxysilane (TEOS). SMS synthesis adds a porosity control to the classical sol-gel synthesis used for enzymes encapsulation. We are reporting here the key parameters of SMS synthesis procedure (amount of amine, TEOS, ethanol, water, lecithin nature, salt addition, etc.), as well as a fine description of SMS structure by TEM. SMS features an isotropic 3-dimensional (3-D) pore structure similarly to SBA-16, but with a lower degree of mesoscopic structural order. Its porosity results from cavities and connecting channels, whose length is controlled by the synthesis conditions. Cavity diameters can reach 4.7 nm in accordance to the lecithin maximum alkyl chain length. Surface areas range from 300 to 800 m 2 /g, and pore volumes from 0.30 to 0.85 mL/g. The use of lactose as an enzyme stabilizing agent does not change the pore structure of SMS. A very fragile enzyme, alcohol dehydrogenase, has been successfully encapsulated by this way, providing the first example of successful entrapment of this enzyme in an inorganic matrix. SMS encapsulation procedure is biomolecules friendly and opens a bright perspective for biomolecules processing for biocatalysis, biosensors or biofuel cell applications.

Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2009

... The second peak at 286.7 eV corresponds to C OH, C O and C N (alcohol, ether, amine) carbon b... more ... The second peak at 286.7 eV corresponds to C OH, C O and C N (alcohol, ether, amine) carbon bond (C2). The third peak at 288.6 eV is indicative of the O C O and C O (double ether, carbonyl) carbon bond (C3). ... C C or C H, C OH, C O or C N, O C O, O C N. ...

Chemistry of Materials, 2005

... Audrey Tourrette, Giuseppe Sparapano, Karine Molvinger, Jean-Marie Devoisselle, Corine Gérard... more ... Audrey Tourrette, Giuseppe Sparapano, Karine Molvinger, Jean-Marie Devoisselle, Corine Gérardin, and Françoise Quignard. ... Hirai, A.; Odani, H.; Nakajima, A. Polym. Bull. 1991, 26, 17. [CrossRef]. (26) Martinsen, A.; Storrø, I.; Skjåk-Bræk. G. Biotechnol. Bioeng.1992, 39, 186. ...

Carbohydrate Polymers, 2010

An innovative strategy for functional finishing of textile materials is based on the incorporatio... more An innovative strategy for functional finishing of textile materials is based on the incorporation of a thin layer of surface modifying systems (SMS) in the form of stimuli-sensitive microgels or hydrogels. Since the copolymerization of poly(N-isopropylacrylamide) with an ionizable polymer, such as chitosan, results in a microgel that is responsive to both temperature and pH, the microparticulate hydrogel of poly-NiPAAmchitosan copolymer (PNCS) was synthesized using surfactant-free emulsion method. The microparticle size in dry (collapsed) state is estimated at 200 nm by SEM and TEM, and effect of temperature and pH on microparticles was investigated by DLS and UV-vis spectrophotometry. The incorporation of PNCS microparticles to cotton material was done by a simple pad-dry-cure procedure from aqueous microparticle dispersion that contained 1,2,3,4-butanetetracarboxylic acid (BTCA) as a crosslinking agent. This application method provided sufficient integrity to coating by maintaining the responsiveness of surface modifying system. The stimuli-responsiveness of modified cotton fabric has been confirmed in terms of regulating its water uptake in dependence of pH and temperature.

Carbohydrate Polymers, 2011

... adsorption increases with the polarity of the surface groups of the polymer, in the order chi... more ... adsorption increases with the polarity of the surface groups of the polymer, in the order chitin < agar ≤ chitosan < carrageenan < alginic acid alginate. The surface area and the mesopore distribution of the aerogels depend both on the dispersion of the parent hydrogel and on ...

Journal of Colloid and Interface Science, 2006

The impregnation of a carrageenan gel by a silica sol is an efficient method to form a composite ... more The impregnation of a carrageenan gel by a silica sol is an efficient method to form a composite material which can be conveniently activated by CO2 supercritical drying. The textural properties of the solids have been characterized by nitrogen adsorption-desorption at 77 K and their composition by thermogravimetric analysis and EDX microprobe. Morphology was examined by SEM. The silica-carrageenan composites present an open macroporous structure. Silica particles retained inside the gel behaved as pillars between the polysaccharide fibrils and form a stick-and-ball network. The stiffening of the carrageenan gel by silica prevented its shrinkage upon drying. The nature of the alkali cations affected the retention of silica particles inside the gel. In the absence of silica, carrageenan fibrils rearrange under supercritical drying and form an aerogel with cavities in the mesopore range.