Collagen structure changes during chrome tanning in propylene carbonate / Yi Zhang in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 1 (Année 2019)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 1 (Année 2019) . - 7 p. Titre : Collagen structure changes during chrome tanning in propylene carbonate Type de document : texte imprimé Auteurs : Yi Zhang, Auteur ; Jenna Kate Buchanan, Auteur ; Geoff Holmes, Auteur ; Bradley William Mansel, Auteur ; Sujay Prabakar, Auteur Année de publication : 2019 Article en page(s) : 7 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse thermique Carbonate de propylène Collagène -- Structure Cuirs et peaux Diffusion de la lumière aux petits angles Tannage au chrome Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Green solvents, such as propylene carbonate (PC), can be used in leather processing to improve the efficiency of chrome tanning and reduce wastewater. Here we report a combined small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) study on PC and its efficacy as a carrier medium during chrome tanning. SAXS analysis on the collagen structure of chrome tanned leather using PC, compared to conventionally tanned leather using water, showed an increase in Cr uptake in addition to the more uniform penetration of Cr through the leather cross-section. The increased binding of Cr to the collagen matrix drives the decreased hydration environment of the collagen triple helix. Furthermore, DSC studies show a uniform hydrothermal stability for the PC samples due to the more even distribution of Cr through the collagen matrix. Understanding the mechanisms by which chrome tanning occurs in non-aqueous solvents can guide us towards a more sustainable future for the leather industry. Note de contenu : - EXPERIMENTAL : Materials - Leather sample preparation - Small-angle X-ray scattering (SAXS) measurements - Differential scanning calorimetry (DSC) measurements - Percentage uptake of chromium - RESULTS AND DISCUSSION : Chromium uptake from AAS studies - SAXS peak changes with tanning - D-period changes through the leather cross-section - Changes in R6/5 - DSC studies DOI : https://doi.org/10.1186/s42825-019-0011-y En ligne : https://link.springer.com/content/pdf/10.1186/s42825-019-0011-y.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36953 [article]

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In-depth understanding of the leather fatliquoring process : A review / M. A. Habib in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 106, N° 1 (01-02/2022)  

[article]  inJOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 106, N° 1 (01-02/2022) . - p. 13-19 Titre : In-depth understanding of the leather fatliquoring process : A review Type de document : texte imprimé Auteurs : M. A. Habib, Auteur Année de publication : 2022 Article en page(s) : p. 13-19 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Collagène -- Structure Emulsification Emulsions Huiles et graisses Produits de nourriture du cuir Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Tanning involves economic and environmental benefits, it transfers low-value by-products (animal hide and skin) into value-added products (natural leather). Introducing fatty matter into the inter-spaces of tanned leather (stiff and unusable) — fatliquoring, restores the fat removed in tanning and restores flexibility to the leather. This article provides an in-depth understanding of the process. Previous chemical treatment and building of a fatliquor emulsion are the watershed points in the process and the main factor affecting the efficiency of the process is the arriva) of the fatty substance to the collagen fibrils which are thus coated with a thin layer of fats that promote sliding of fibrils and prevent adhesion. Successful fatliquoring is achieved through using an emulsion of specific particle size to enable the oil droplets to penetrate the leather reaching to fibril level. Note de contenu : - Collagen protein structure - Fibril bundles and fatliquor mechanism - Emulsifying of fatty matter and emulsion efficiency - Types of fatliquor emulsion - Modified natural oil and fat used in fatliquoring En ligne : https://drive.google.com/file/d/1D3rKpsxbZyVW-TQFEarRV5giierkoamK/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36968 [article]

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Quantitative and structural analysis of isotopically labelled natural crosslinks in type I skin collagen using LC-HRMS and SANS / Yi Zhang in JOURNAL OF LEATHER SCIENCE AND ENGINEERING, Vol. 1 (Année 2019)  

[article]  inJOURNAL OF LEATHER SCIENCE AND ENGINEERING > Vol. 1 (Année 2019) . - 9 p. Titre : Quantitative and structural analysis of isotopically labelled natural crosslinks in type I skin collagen using LC-HRMS and SANS Type de document : texte imprimé Auteurs : Yi Zhang, Auteur ; Rafea Naffa, Auteur ; Christopher J. Garvey, Auteur ; Catherine Maidment, Auteur ; Sujay Prabakar, Auteur Année de publication : 2019 Article en page(s) : 9 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Analyse quantitative (chimie) Chromatographie en phase liquide Collagène -- Structure Cuirs et peaux Réticulation (polymérisation) Spectrométrie de masse Traceurs radioactifs Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Collagen structure in biological tissues imparts its intrinsic physical properties by the formation of several covalent crosslinks. For the first time, two major crosslinks in the skin dihydroxylysinonorleucine (HLNL) and histidinohydroxymerodesmosine (HHMD), were isotopically labelled and then analysed by liquid-chromatography high-resolution accurate-mass mass spectrometry (LC-HRMS) and small-angle neutron scattering (SANS). The isotopic labelling followed by LC-HRMS confirmed the presence of one imino group in both HLNL and HHMD, making them more susceptible to degrade at low pH. The structural changes in collagen due to extreme changes in the pH and chrome tanning were highlighted by the SANS contrast variation between isotopic labelled and unlabelled crosslinks. This provided a better understanding of the interaction of natural crosslinks with the chromium sulphate in collagen suggesting that the development of a benign crosslinking method can help retain the intrinsic physical properties of the leather. This analytical method can also be applied to study artificial crosslinking in other collagenous tissues for biomedical applications. Note de contenu : - EXPERIMENTAL METHODS : Materials and methods - RESULTS AND DISCUSSION : Characterization of natural crosslinks in skin collagen : isotopic labelling using NaBD4 and mechanism of HHMD formation - Quantification of natural crosslinks in skin collagen : relationship with pH and crosslinking conditions - Structural analysis of skin collagen : interplay between natural and artificial crosslinks - Table 1 : Collagen D-periodicity at different processing stages in control, reduced and labelled skin samples. The D-period decreased for all samples starting from raw to the pickled stage, then increased at the crosslinked stage DOI : https://doi.org/10.1186/s42825-019-0012-x En ligne : https://link.springer.com/content/pdf/10.1186/s42825-019-0012-x.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36955 [article]

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Structure, extraction, processing, and applications of collagen as an ideal component for biomaterials - a review / Qijue Chen in COLLAGEN AND LEATHER, Vol. 5 (2023)  

[article]  inCOLLAGEN AND LEATHER > Vol. 5 (2023) . - 27 p. Titre : Structure, extraction, processing, and applications of collagen as an ideal component for biomaterials - a review Type de document : texte imprimé Auteurs : Qijue Chen, Auteur ; Ying Pei, Auteur ; Keyong Tang, Auteur ; Madalina Georgiana Albu-Kaya, Auteur Année de publication : 2023 Article en page(s) : 27 p. Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Biomatériaux Collagène -- Structure Extraction (chimie) Systèmes auto-assemblés Index. décimale : 574.192 Biochimie Résumé : Collagen with a multi-hierarchical architecture exhibits powerful biological performance, thus being developed in biomedical applications as a processing building block. The isolated collagen after extraction from biological tissues can be processed into various forms such as fibrils, scaffolds, membranes, microspheres, hydrogels, and sponges for further use in specific applications. This review briefly discusses the multi-hierarchical structure, powerful biological performances, extraction, and processing approaches of collagen as a natural biomaterial. The processing of collagen including dissolution, self-assembly, cross-linking, and electrospinning, is discussed to show more feasibility for specific applications of collagen composite biomaterials. Further emphasis is directed towards the biomedical applications of drug and gene delivery, as well as tissue repair involving bone, cartilage, vascular, and corneal, along with wound healing. Additionally, there is a focus on the development of flexible sensors and electronic skins (e-skins). Furthermore, the potential challenges and perspectives for the development of collagen-based biomaterials are proposed. In short, collagen-based biomaterials are expected to facilitate sustainable development and the next generation of advanced biomaterial applications. Note de contenu : - COLLAGEN SUPERFAMILLY : Collagen types - Hierarchical structure of type I collagen - Powerful biological performances of collagen - Antioxidant ability - Inhibitory activity - Antitumor activity - Anti-freeze activity - Regulating biological activities - Involving the tissue recovery - EXTRACTION AND PROCESSING OF COLLAGEN : Extraction of collagen - Processing of collagen - COLLAGEN-BASED BIOMEDICAL APPLICATIONS - Drug and gene delivery - Tissue repairing - Smart-healthcare devices DOI : https://doi.org/10.1186/s42825-023-00127-5 En ligne : https://link.springer.com/content/pdf/10.1186/s42825-023-00127-5.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40070 [article]

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