1-butyl-3-methylimidazolium acetate as an alternative solvent for type I collagen / Jie Liu in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CIX, N° 6 (06/2014)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CIX, N° 6 (06/2014) . - p. 189-196 Titre : 1-butyl-3-methylimidazolium acetate as an alternative solvent for type I collagen Type de document : texte imprimé Auteurs : Jie Liu, Auteur ; Zhou Xu, Auteur ; Chen Yi, Auteur ; Haojun Fan, Auteur ; Bi Shi, Auteur Année de publication : 2014 Article en page(s) : p. 189-196 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Chimie analytique Collagène -- Solubilité Solvants -- Suppression ou remplacement Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Low solubility and undesirable denaturation in conventional solvents continue to represent a significant challenge for efficient extraction, accurate characterization and versatile processing of collagen. In the present study, a room temperature ionic liquid (IL), 1-butyl-3-methylimidazolium acetate ([BMIM]Ac), was synthesized, and then evaluated as an alternative solvent for type I collagen. Real-time polarizing optical microscope observation indicated complete disintegration of hierarchical structure of collagen aggregates as solubilized in [BMIM]Ac at 25°C. The solubility reached up to approximately 8.0 wt.% at 25°C, more than ten times higher than that in conventional dilute acetic acid. In comparison with dilute acetic acid and recently reported chloridion ILs, high solubility of collagen in [BMIM]Ac at room temperature was ascribed to loose binding between [BMIM]+ and acetate, as well as stronger proton-accepting ability of [BMIM]Ac, which enabled rupture of those intermolecular hydrogen bonds and ionic bonds that stabilized collagen aggregates. However, such bond-rupturing effect was found selective at room temperature. As demonstrated by Fourier transform infrared, circular dichroism, atomic force microscope, and ultrasensitive differential scanning calorimetry analysis, [BMIM]Ac did not destroy the special triple-helical structure of tropocollagen molecules that had been identified as being of importance for the functional and bioactive properties of collagen. According to these results, the discovery of [BMIM]Ac as an ideal solvent for collagen may open up new possibilities for the chemistry and engineering of collagen, which has long been established as a readily accessible and renewable resource with many unique properties. Note de contenu : - EXPERIMENTAL : Materials - Synthesis of [BMIM]Ac - Dissolution of collagen in [BMIM]Ac - Polarizing optical microscope (POM) observation - FTIR analysis - CD measurement - AFM observation - DSC measurement - RESULTS AND DISCUSSION : Dissolution mechanism of collagen in [BMIM]Ac - Triple-helical structure of collagen regenerated from [BMIM]Ac En ligne : https://drive.google.com/file/d/1sm3cYDSvhjqbYBv8WJIDxo4nbF5k-kaO/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=21517 [article]

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Investigation of the solubility and dispersion degree of calf skin collagen in ionic liquids / Sicong Liu in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 1 (Année 2019)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 1 (Année 2019) . - 12 p. Titre : Investigation of the solubility and dispersion degree of calf skin collagen in ionic liquids Type de document : texte imprimé Auteurs : Sicong Liu, Auteur ; Qian Li, Auteur ; Li Guoying, Auteur Année de publication : 2019 Article en page(s) : 12 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Bovins -- Races Chimie analytique Collagène Collagène -- Analyse Collagène -- Solubilité Dispersions et suspensions Liquides ioniques Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The dissolution of collagen in ionic liquids (ILs) was highly dependent on the polarity of ILs, which was influenced by their sorts and concentrations. Herein, the solubility and dispersion degree of collagen in two sorts of ILs, namely 1-ethyl-methylimidazolium tetrafluoroborate ([EMIM][BF4]) with low polarity and 1-ethyl-3-methylimidazolium acetate ([EMIM][Ac]) with high polarity in a concentration range from 10% to 70% at 10 °C were investigated. When 150 mg of collagen was added to 30 mg of ILs, the minimum soluble collagen concentration was 0.02 mg/mL in 70% [EMIM][BF4] with lowest polarity and the maximum was 3.57 mg/mL in 70% [EMIM][Ac] with highest polarity, which indicates that soluble collagen and insoluble collagen fibers were both present. For insoluble collagens, differential scanning calorimetry showed that the thermal-stability was weakened when increasing the ILs concentration and polarity, and the fiber arrangement was looser with a more uniform lyophilized structure, observed by atomic force microscopy and scanning electron microscopy. For soluble collagens, electrophoresis patterns and Fourier transform infrared spectroscopy showed that no polypeptide chain degradation occurred during dissolution, but the thermal denaturation temperature decreased by 0.26 °C~ 7.63 °C with the increase of ILs concentrations, measured by ultra-sensitive differential scanning calorimetry. Moreover, the aggregation of collagen molecules was reduced when ILs polarity was increased as determined by fluorescence measurements and dynamic light scattering, which resulted in an increased loose fiber arrangement observed by atomic force microscopy. If the structural integrity of collagen needs to be retained, then the ILs sorts and concentrations should be considered. Note de contenu : - EXPERIMENTAL : Materials - Processing collagen with ILs - Collagen solubility in ILs - DSC of insoluble collagen fibrils - SEM of insoluble collagen fibrils - AFM measurements of insoluble and soluble collagen - SDS–PAGE patterns of soluble collagen - FTIR of soluble collagen - Fluorescence measurements of soluble collagen - DLS measurements of soluble collagen - RESULTS AND DISCUSSION : Solubility of collagen in ILs - Thermal analysis of insoluble collagen fibrils - SEM images of insoluble collagen fibrils - AFM images of insoluble collagen fibrils - SDS-PAGE patterns of soluble collagen - FTIR spectra analysis of soluble collagen - Thermal analysis of soluble collagen - Fluorescence analysis of soluble collagen - DLS analysis of soluble collagen - AFM images of soluble collagen - Table 1 The concentration of soluble collagen in different ILs and concentrations - Table 2 Thermodynamic parameters of Col and collagen samples dissolved in different concentrations of [EMIM][Ac]a DOI : https://doi.org/10.1186/s42825-019-0013-9 En ligne : https://link.springer.com/content/pdf/10.1186/s42825-019-0013-9.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36945 [article]

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Method to extract water-soluble collagen from induced biphasic commercial gel / Matthew J. Mastauskas in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CVII, N° 7 (07/2012)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CVII, N° 7 (07/2012) . - p. 243-248 Titre : Method to extract water-soluble collagen from induced biphasic commercial gel Type de document : texte imprimé Auteurs : Matthew J. Mastauskas, Auteur ; Gennaro J. Maffia, Auteur Année de publication : 2012 Article en page(s) : p. 243-248 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Collagène -- Solubilité Eau Extraction (chimie) Gel de collagène Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Water-soluble collagen extracted from commercial collagen gel could be a possible replacement for water-insoluble collagen fibrils, which are currently extracted from raw corium. If the water-soluble collagen proves to be a suitable replacement in the various water-insoluble collagen applications as mention in this paper, then the time-intensive milling process could be avoided. The first part of the process as described in this paper is a method to extract the water-soluble collagen. Water-soluble collagen was extracted from commercial collagen gel by mixing distilled water with the collagen gel, centrifugation, decanting, freezing and vacuum drying the supernate. Various ratios of commercial collagen gel to water ranging from 10% to 90% commercial collagen gel to water were examined based upon the extraction and performance of gravimetric analyses on the water-soluble collagen. The commercial collagen gel to water ratio had an effect on the mass fraction of extracted water-soluble collagen. Greater amounts of water-soluble collagen could be extracted by using lesser amounts of commercial collagen gel. The water-soluble collagen matrices had a mesh-like appearance similar to cotton, except that they could be flattened easily and could not retain their original shape. The water-soluble collagen matrices were formed into a chaotic, non-uniform manner caused by the re-constituting of fibers during the freezing and vacuum drying process. Note de contenu : - INTRODUCTION : Introduction to collagen - Water-soluble collagen - EXPERIMENTAL : Experimental overview - Materials - Centrifugation study - Extraction process - RESULTS AND DISCUSSION : Collagen composition of commercial collagen gel - Mass fraction of water-soluble collagen matrices - Microscopy of commercial collagen gel - Microscopy of water-soluble collagen matrix - SEM - waterxoluble collagen matrix - CONCLUSIONS : Collagen composition of commercial collagen gel - Mass fraction of water-soluble collagen matrices - Microscopy of commercial collagen gel - Microscopy of water-soluble collagen matrices - SEM - water-soluble collagen matrices En ligne : https://drive.google.com/file/d/1FwN0_eWMG-lD3IVo86Y7ubbXTn2Wvcz4/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15644 [article]

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Novel approach for the removal of organic contaminants in wastewaters : adsolubilization of 2-naphthol onto collagen fibres / Fernando Maldonado in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 97, N° 3 (05-06/2013)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 97, N° 3 (05-06/2013) . - p. 105-110 Titre : Novel approach for the removal of organic contaminants in wastewaters : adsolubilization of 2-naphthol onto collagen fibres Type de document : texte imprimé Auteurs : Fernando Maldonado, Auteur ; Albert M. Manich, Auteur ; Agusti Marsal, Auteur Année de publication : 2013 Article en page(s) : p. 105-110 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cinétique chimique Collagène -- Solubilité Dodécyl sulfate de sodium Le laurylsulfate de sodium (LSS) ou dodécylsulfate de sodium (SDS) est un détergent et tensioactif ionique fort, couramment utilisé en biochimie et biologie moléculaire. C'est un composé à ne pas confondre avec le laureth sulfate de sodium. La concentration micellaire critique du SDS varie de 0,007 à 0,01 mol/L dans l'eau à 25°C. Le dodécylsulfate de sodium (en anglais, Sodium Dodecyl Sulfate ou SDS ou/ NaDS), de formule C12H25NaO4S, aussi connu sous le nom de laurylsulfate de sodium (en anglais, sodium lauryl sulfate ou SLS), est un tensioactif ionique qui est utilisé dans les produits ménagers tels que les dentifrices, shampooings, mousses à raser ou encore bains moussants pour ses effets épaississants et sa capacité à créer une mousse, il est également repris comme additif alimentaire par le codex alimentarius (E487). La molécule est composée d’une chaîne de 12 atomes de carbone, rattachée à un groupement sulfate conférant à la molécule les propriétés amphiphiles requises pour un détergent. Le SDS est préparé par sulfonation du dodécanol (alcool de lauryl, C12H25OH), suivie par une neutralisation par du carbonate de sodium. Le SDS est utilisé aussi bien dans les procédés industriels que pour les produits cosmétiques destinés au grand public. Eaux usées -- Décontamination Electrolytes Isotherme d'adsorption Naphtols pH Polluants organiques Thermodynamique Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Research on adsolubilization to fibrous proteins, such as collagen, has received little attention despite its academic relevance and potential industrial applications. The aim of this work was to study the influence of different parameters on adsolubilization onto collagen fibres using 2-naphthol as a model substance in order to verify the feasibility of this process in removing organic contaminants from wastewaters. The collagen fibres were previously or simultaneously treated with an anionic surfactant under mild acidic aqueous conditions to form the admicelles. The following parameters were considered: shaking time, surfactant type (sodium dodecyl sulphate and sodium dodecylbenzene sulphonate); influence of pH; presence of electrolytes and polarity of the medium. Adsolubilization isotherms were obtained at 10, 20, 25, 30 and 35°C and the kinetic study of adsolubilization was also measured. Thermodynamic parameters such as enthalpy change, entropy change and free energy change were calculated by applying the van't Hoff equation for adsolubilization of 2-naphthol. The higher adsolubilization capacity of 2-naphthol was reached at acidic pH and equilibrium was achieved after two hours of treatment. The presence of ethanol in the batch considerably lowered the adsolubilization capacity of fibrous collagen. Thermodynamic parameters indicated that the adsolubilization process is exothermic and spontaneous. The kinetic study revealed that adsolubilization of 2-naphthol onto collagen fibres is best described by a pseudo-second order model. Our results open the door to the use of collagen fibres in the separation of organic contaminants from wastewaters through adsolubilization. Note de contenu : - AIM OF THE WORK - EXPERIMENTAL PROCEDURES : Materials - Methods - RESULTS AND DISCUSSION : Effect of shaking time - Effect of pH - Influence of the ionic strength - Influence of the polarity of the medium - Influence of the initial amount of SDS - Adsorption and adsolubilization isotherms - Influence of temperature. Thermodynamic parameters - Adsolubilization kinetics of 2-naphthol onto SDS-hp En ligne : https://drive.google.com/file/d/1wUnnBflsaPkBGGOfprh42JyIx4Ky9koX/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=18838 [article]

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Physiological and cell biological properties in vitro of collagen isolated from calf limed splits / G. I. Ly in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 88, N° 2 (03-04/2004)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 88, N° 2 (03-04/2004) . - p. 66-71 Titre : Physiological and cell biological properties in vitro of collagen isolated from calf limed splits Type de document : texte imprimé Auteurs : G. I. Ly, Auteur ; Shigeharu Fukunaga, Auteur ; K. Takenouchi, Auteur ; F. Nakamura, Auteur Année de publication : 2004 Article en page(s) : p. 66-71 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cellules -- Adhésivité Cellules -- Prolifération Collagénases Les collagénases sont des enzymes capables de rompre les liaisons peptidiques du collagène. Elles facilitent la destruction des structures extracellulaires lors de la pathogenèse bactérienne. Ce sont des exotoxines. La production de collagénases peut être induite lors d'une réponse immunitaire, par les cytokines qui stimulent les cellules telles que les fibroblastes et les ostéoplastes et occasionnent indirectement des lésions tissulaires. Collagène -- Analyse Collagène -- Solubilité Cuirs et peaux de veaux Fibrilles de collagène La fibrille de collagène est une structure constituée d'un assemblage de fibres de tropocollagène (assemblage de 3 protéines de collagène alpha (alpha 1 - alpha 1 - alpha 2) en une hélice droite. Kératinocytes Les kératinocytes sont des cellules constituant 90 % de la couche superficielle de la peau (épiderme) et des phanères (ongles, cheveux, poils, plumes, écailles). Ils synthétisent la kératine (kératinisation), une protéine fibreuse et insoluble dans l'eau, qui assure à la peau sa propriété d'imperméabilité et de protection extérieure. L'épiderme est divisé en 4 couches basées sur la morphologie des kératinocytes (de l'intérieur vers l'extérieur) : 1. stratum germinativum (couche basale à la jonction avec le derme) 2. stratum spinosum 3. stratum granulosum 4. stratum lucidum 5. stratum corneum Les kératinocytes passent progressivement de la couche basale vers les couches supérieures par différenciation cellulaire jusqu'au stratum corneum ou ils forment une couche de cellules mortes nommées squames, par apoptose. Cette couche constitue une barrière de protection et réduit la perte d'eau de l'organisme. Les kératinocytes sont en perpétuel renouvellement. Ils mettent environ 1 mois pour aller de la couche basale au stratum corneum mais ce processus peut être accéléré en cas d'hyperprolifération de kératinocyte (psoriasis). Systèmes auto-assemblés Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Experiments on self-assembly, susceptibility to collagenase degradation and activity for cell adhesion were carried out to determine the differences between collagen isolated from calf limed splits with acetic acid, alkali or pepsin treatment and commercial type I collagen produced from fresh bovine skins with acetic acid. Self-assembly was observed in all collagen solutions; however, fibril formation of acetic acid-treated collagen and pepsin-treated collagen was observed at neutral pH, as was that of commercial type I collagen whereas, alkali-treated collagen lost its ability of assembly at neutral pH but was able to form fibrils under acidic conditions. Scanning electron microscopy showed that the assembled fibrils from acetic acid-treated collagen had a major fibrous and minor membranous structure similar to that of commercial type I collagen but that reconstructed fibrils from pepsin-treated collagen were more rectilinear and evenly dispersed than were those of other collagens. Analysis by sodium dodecyl sulphatepolyacrylamide gel electrophoresis revealed that matrix metalloproteinase (MMP-1) cleaved collagen isolated from limed splits at a similar locus to that of commercial type I collagen. Keratinocytes cultured on collagen showed increased rates of attachment and proliferation. Moreover, pepsin-treated collagen had more significant effects on cell attachment and proliferation than commercial acetic acid-extracted type I collagen. Note de contenu : - EXPERIMENTAL METHODS : Preparation of limed splits and solubilized collagen - Collagen fibril formation - Scanning electron microscopy - Collagen digestion with collagenase - Isolation and culture of keratinocytes - Cell adhesive assay - Cell viability and proliferation assay - RESULTS AND DISCUSSION : Collagen self-assembly - Susceptibility to MMP-1 collagenase digestion - Cell adhesion to collagen En ligne : https://drive.google.com/file/d/1oyUIZqFKFf7bHK5bSlsnMk8zFL2wJeYM/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=39644 [article]

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Rheological behaviour of alkali solubilized collagen from limed bovine split wastes / Chen Yihui in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 97, N° 5 (09-10/2013)  

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The influence of some enzyme preparations on components of skin / M. A. Urbaniak in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 57 (Année 1973)  

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