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Kono H, Hara H, Iijima K, Fujita S, Kondo N, Hirabayashi K, Isono T, Ogata M. Preparation and characterization of carboxymethylated Aureobasidium pullulans β-(1 → 3, 1 → 6)-glucan and its in vitro antioxidant activity. Carbohydr Polym 2023; 322:121357. [PMID: 37839833 DOI: 10.1016/j.carbpol.2023.121357] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/12/2023] [Accepted: 08/28/2023] [Indexed: 10/17/2023]
Abstract
Aureobasidium pullulans β-(1 → 3, 1 → 6)-glucan (APG) has a high degree of β-(1 → 6)-glucosyl branching and a regular triple helical structure similar to that of schizophyllan. In this study, APG was carboxymethylated to different degrees of substitution (DS = 0.51, 1.0, and 2.0, denoted CMAPG 1-3, respectively) using a heterogeneous reaction. With increasing DS, the triple-helix structure drastically decreased and converted to a random coil structure in CMAPG 3. Further, aqueous solutions of CMAPG changed from pseudoplastic fluids to perfect Newtonian liquids with increasing DS, indicating that the intra- and intermolecular hydrogen bonds had been cleaved by the substituents to form a random coil structure. In addition, APG and CMAPG solutions exhibited scavenging ability against hydroxyl, organic, and sulfate radicals. It was also found that the carboxymethylation of APG drastically enhanced the organic radical scavenging ability. On the basis of the relationship between the DS and radical scavenging ability of the CMAPG samples, we believe hydroxyl and organic radicals were preferably scavenged by the donation of hydrogen atoms from the glucose rings and the methylene moieties of the carboxymethyl groups, respectively. Considering the obtained results, CMAPG and APG are expected to have applications in pharmaceuticals, functional foods, and cosmetics as antioxidant polysaccharides.
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Affiliation(s)
- Hiroyuki Kono
- Division of Applied Chemistry and Biochemistry, National Institute of Technology, Tomakomai College, Nishikioka 443, Tomakomai, Hokkaido 059 1275, Japan.
| | - Hideyuki Hara
- Bruker Japan K. K., Moriya-cho 3-9, Kanagawa-ku, Yokohama, Kanagawa 221 0022, Japan
| | - Kokoro Iijima
- Division of Applied Chemistry and Biochemistry, National Institute of Technology, Tomakomai College, Nishikioka 443, Tomakomai, Hokkaido 059 1275, Japan
| | - Sayaka Fujita
- Division of Applied Chemistry and Biochemistry, National Institute of Technology, Tomakomai College, Nishikioka 443, Tomakomai, Hokkaido 059 1275, Japan
| | - Nobuhiro Kondo
- Itochu Sugar Co. Ltd, Tamatsuura 3, Hekinan, Aichi 447 8506, Japan; WELLNEO SUGAR Co., Ltd., 14-1 Nihonbashi-Koamicho, Chuo-ku, Tokyo 103 8536, Japan
| | - Katsuki Hirabayashi
- Itochu Sugar Co. Ltd, Tamatsuura 3, Hekinan, Aichi 447 8506, Japan; WELLNEO SUGAR Co., Ltd., 14-1 Nihonbashi-Koamicho, Chuo-ku, Tokyo 103 8536, Japan
| | - Takuya Isono
- Faculty of Engineering, Hokkaido University, N13W8, Kita-ku, Sapporo, Hokkaido 060 8628, Japan
| | - Makoto Ogata
- Faculty of Food and Agricultural Sciences, Fukushima University, 1 Kanayagawa, Fukushima, Fukushima 960 1296, Japan
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He X, Sun C, Khalesi H, Yang Y, Zhao J, Zhang Y, Wen Y, Fang Y. Comparison of cellulose derivatives for Ca 2+ and Zn 2+ adsorption: Binding behavior and in vivo bioavailability. Carbohydr Polym 2022; 294:119837. [PMID: 35868780 DOI: 10.1016/j.carbpol.2022.119837] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 06/27/2022] [Accepted: 07/04/2022] [Indexed: 11/29/2022]
Abstract
Cellulose with distinct colloidal states exhibited different adsorption capability for ions and whether the intake of cellulose would bring positive or negative influence on the mineral bioavailability is inconclusive. This work investigated the binding behavior of carboxymethyl cellulose (CMC), TEMPO-oxidized nanofibrillated/nanocrystalline cellulose (TOCNF/TOCNC), and microcrystalline cellulose (MCC) with Ca2+and Zn2+ and compared their effects on mineral bioavailability in vitro and in vivo. The results suggested that CMC displayed a higher adsorption capability (36.6 mg g-1 for Ca2+ and 66.2 mg g-1 for Zn2+) than the other types of cellulose because of the strong interaction between carboxyl groups of cellulose and the ions. Although the cellulose derivatives had adverse effects on ion adsorption in vitro, the fermentability endowed by TOCNF/TOCNC counterbalanced the negative impacts in vivo. The findings suggested that the colloidal states of cellulose affected the bioavailability of minerals and could provide useful guidance for applications of specific cellulose.
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Affiliation(s)
- Xiangxiang He
- Department of Food Science and Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Cuixia Sun
- Department of Food Science and Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hoda Khalesi
- Department of Food Science and Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yuyan Yang
- Department of Food Science and Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jingwen Zhao
- Department of Food Science and Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yin Zhang
- Key Laboratory of Meat Processing of Sichuan, Chengdu University, Chengdu 610106, China
| | - Yangbing Wen
- Tianjin Key Laboratory of Pulp and Paper, Tianjin University of Science & Technology, Tianjin 300457, China
| | - Yapeng Fang
- Department of Food Science and Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
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Elucidation of substituent distribution states for carboxymethyl chitosan by detailed NMR analysis. CARBOHYDRATE POLYMER TECHNOLOGIES AND APPLICATIONS 2021. [DOI: 10.1016/j.carpta.2021.100175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
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Cai Z, Zhang H. The effect of carboxymethylation on the macromolecular conformation of the (1 → 3)-β -D-glucan of curdlan in water. Carbohydr Polym 2021; 272:118456. [PMID: 34420716 DOI: 10.1016/j.carbpol.2021.118456] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/14/2021] [Accepted: 07/15/2021] [Indexed: 11/28/2022]
Abstract
The chain conformational change in curdlan during carboxymethylation was investigated using nuclear magnetic resonance (NMR), circular dichroism (CD) spectroscopy, and atomic force microscopy (AFM). The distributions of carboxymethyl substituents within anhydroglucose unit (AGU) of CMCD were found to follow the order of OH (6) > OH (4) > OH (2) for CMCD with a low DS and OH (6) > OH (2) > OH (4) for CMCD with relatively high DS. The increased carboxymethylation level induced the chain conformation transition of curdlan from triple helix to random coil in water. The DS of 0.25 was the critical value of chain conformation transition, below which CMCD chains were triple helices. For DS larger than 0.25, CMCD existed in the state of random coils. The intermolecular hydrogen bonding between C2 hydroxyls in AGU sustained the triple helical conformation and stiffness of the polymer chain, which weakened with the increase in DS.
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Affiliation(s)
- Zhixiang Cai
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Key Laboratory of Electrical Insulation and Thermal Aging, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hongbin Zhang
- Department of Polymer Science and Engineering, School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Key Laboratory of Electrical Insulation and Thermal Aging, Shanghai Jiao Tong University, Shanghai 200240, China.
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Gürer F, Kargl R, Bračič M, Makuc D, Thonhofer M, Plavec J, Mohan T, Kleinschek KS. Water-based carbodiimide mediated synthesis of polysaccharide-amino acid conjugates: Deprotection, charge and structural analysis. Carbohydr Polym 2021; 267:118226. [PMID: 34119179 DOI: 10.1016/j.carbpol.2021.118226] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 04/30/2021] [Accepted: 05/16/2021] [Indexed: 11/17/2022]
Abstract
We report here a one-step aqueous method for the synthesis of isolated and purified polysaccharide-amino acid conjugates. Two different types of amino acid esters: glycine methyl ester and L-tryptophan methyl ester, as model compounds for peptides, were conjugated to the polysaccharide carboxymethylcellulose (CMC) in water using carbodiimide at ambient conditions. Detailed and systematic pH-dependent charge titration and spectroscopy (infrared, nuclear magnetic resonance: 1H, 13C- DEPT 135, 1H- 13C HMBC/HSQC correlation), UV-vis, elemental and ninhydrin analysis provided solid and direct evidence for the successful conjugation of the amino acid esters to the CMC backbone via an amide bond. As the concentration of amino acid esters increased, a conjugation efficiency of 20-80% was achieved. Activated charcoal aided base-catalyzed deprotection of the methyl esters improved the solubility of the conjugates in water. The approach proposed in this work should have the potential to tailor the backbone of polysaccharides containing di- or tri-peptides.
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Affiliation(s)
- Fazilet Gürer
- Laboratory for Characterisation and Processing of Polymers, Faculty of Mechanical Engineering, University of Maribor, Smetanova Ulica 17, 2000 Maribor, Slovenia
| | - Rupert Kargl
- Institute of Chemistry and Technology of Biobased System (IBioSys), Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria; Institute of Automation, Faculty of Electrical Engineering and Computer Science, University of Maribor, Koroška cesta 46, 2000 Maribor, Slovenia
| | - Matej Bračič
- Laboratory for Characterisation and Processing of Polymers, Faculty of Mechanical Engineering, University of Maribor, Smetanova Ulica 17, 2000 Maribor, Slovenia
| | - Damjan Makuc
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia
| | - Martin Thonhofer
- Institute of Chemistry and Technology of Biobased System (IBioSys), Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria
| | - Janez Plavec
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia; EN-FIST Centre of Excellence, Trg OF 13, SI-1000 Ljubljana, Slovenia; Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
| | - Tamilselvan Mohan
- Laboratory for Characterisation and Processing of Polymers, Faculty of Mechanical Engineering, University of Maribor, Smetanova Ulica 17, 2000 Maribor, Slovenia; Institute of Chemistry and Technology of Biobased System (IBioSys), Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria.
| | - Karin Stana Kleinschek
- Institute of Chemistry and Technology of Biobased System (IBioSys), Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria; Institute of Automation, Faculty of Electrical Engineering and Computer Science, University of Maribor, Koroška cesta 46, 2000 Maribor, Slovenia.
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Fast and practical synthesis of carboxymethyl cellulose from office paper waste by ultrasonic-assisted technique at ambient temperature. Polym Degrad Stab 2021. [DOI: 10.1016/j.polymdegradstab.2020.109473] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Kono H, Numata J. Substituent distribution of propyl cellulose studied by nuclear magnetic resonance. Carbohydr Res 2020; 495:108067. [PMID: 32739678 DOI: 10.1016/j.carres.2020.108067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/08/2020] [Accepted: 06/08/2020] [Indexed: 11/30/2022]
Abstract
A series of propyl cellulose (PC) samples with different degrees of substitution (DS) ranging from 0.34 to 2.02 were prepared by a slurry method using propyl bromide as the etherification reagent. Two-dimensional nuclear magnetic resonance (NMR) studies were performed to identify the 1H and 13C chemical shifts of eight anhydroglucose units (AGUs) in PC chains including un-, 2-mono-, 3-mono-, 6-mono-, 2,3-di-, 2,6-di-, 3,6-di-, and 2,3,6-tri-substituted ones. In addition, the mole fractions (χ) of these AGUs in the studied PC samples and their changes with DS were determined from the quantitative 13C NMR spectra. The obtained χ-DS profiles were different from those of methyl and ethyl celluloses prepared by a similar slurry method, indicating that the molecular sizes of the substituent reagents utilized for cellulose ethers strongly affected their substituent distributions.
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Affiliation(s)
- Hiroyuki Kono
- Division of Applied Chemistry and Biochemistry, National Institute of Technology, Tomakomai College, Nishikioka 443, Tomakomai, Hokkaido, 059 1275, Japan.
| | - Jun Numata
- Division of Applied Chemistry and Biochemistry, National Institute of Technology, Tomakomai College, Nishikioka 443, Tomakomai, Hokkaido, 059 1275, Japan
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Bahrpaima K, Fatehi P. Preparation and Coagulation Performance of Carboxypropylated and Carboxypentylated Lignosulfonates for Dye Removal. Biomolecules 2019; 9:biom9080383. [PMID: 31434221 PMCID: PMC6723465 DOI: 10.3390/biom9080383] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 08/14/2019] [Accepted: 08/14/2019] [Indexed: 01/15/2023] Open
Abstract
In this work, 1-carboxypropyled (1-CPRLS) and 5-carboxypentyled lignosulfonates (5-CPELS) were synthesized using 2-chlorobutanoic acid and 6-chlorohexanoic acid as carboxylate group donors via SN1 and SN2 mechanisms, respectively. 1-Carboxypropyl and 5-carboxypentyl lignosulfonates with the charge densities of −3.45 and −2.94 meq g−1 and molecular weights of 87,900 and 42,400 g·mol−1 were produced, respectively, under mild conditions. The carboxylate content and degree of substitution (DS) of the 1-CPRLS product were 2.37 mmol·g−1 and 0.70 mol·mol−1, while those of 5-CPELS products were 2.13 mmol·g−1 and 0.66 mol·mol−1, respectively. The grafting of carboxypropyl and carboxypentyl groups to lignosulfonate was confirmed by Fourier transform infrared (FT-IR) and nuclear magnetic resonance (1H-NMR and 13C-NMR) spectroscopies. In addition, 1-CPRLS and 5-CPELS were applied as coagulants for removing ethyl violet (EV) dye from a simulated solution, and their performance was related to their charge densities and molecular weights. Furthermore, fundamental discussion is provided on the advantages of (1) producing 1-CPRLS and (2) the superior properties and performance of 1-CPRLS to carboxyethylated lignosulfonate.
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Affiliation(s)
- Khatereh Bahrpaima
- Department of Chemical Engineering, Lakehead University, Thunder Bay, ON P7B 5E1, Canada
| | - Pedram Fatehi
- Department of Chemistry, Firoozabad Branch, Islamic Azad University, Firoozabad 74719-13113, Iran.
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Pettignano A, Charlot A, Fleury E. Solvent-Free Synthesis of Amidated Carboxymethyl Cellulose Derivatives: Effect on the Thermal Properties. Polymers (Basel) 2019; 11:polym11071227. [PMID: 31340491 PMCID: PMC6680703 DOI: 10.3390/polym11071227] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 07/18/2019] [Accepted: 07/19/2019] [Indexed: 11/16/2022] Open
Abstract
The present work explores the possibility of chemically modifying carboxymethyl cellulose (CMC), a widely diffused commercial cellulose ether, by grafting of hydrophobic moieties. Amidation of CMC, at high temperature and in heterogeneous conditions, was selected as synthetic tool for grafting on CMC a panel of commercially available amines (bearing long aliphatic chains, alkyl aromatic and heteroaromatic groups, more or less spaced from the cellulose backbone). The reaction was successfully carried out in absence of solvents, catalysts and coupling agents, providing a promising and more sustainable alternative to conventional amidation procedures. Relationships between the chemical structure of the obtained CMC derivatives and their thermal properties were carefully studied, with a particular attention to the thermal behavior. Grafting of aromatic and heteroaromatic alkyl amines, presenting a linear alkyl chain between CMC backbone and a terminal bulky moiety, allowed for efficiently separating the polysaccharide chains, improving their mobility and resulting in a consequent lowering of the glass transition temperature (Tg). The Tg values obtained (90-147 °C) were found to be closely dependent on both the size of the aliphatic spacer, the structure of the aromatic ring and the extent of amidation.
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Affiliation(s)
- Asja Pettignano
- Université de Lyon, INSA LYON, Ingénierie des Matériaux Polymères IMP-UMR CNRS 5223, F 69621 Villeurbanne, France
| | - Aurélia Charlot
- Université de Lyon, INSA LYON, Ingénierie des Matériaux Polymères IMP-UMR CNRS 5223, F 69621 Villeurbanne, France.
| | - Etienne Fleury
- Université de Lyon, INSA LYON, Ingénierie des Matériaux Polymères IMP-UMR CNRS 5223, F 69621 Villeurbanne, France.
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Yan Q, Liu L, Wang T, Wang H. A pH-responsive hydrogel system based on cellulose and dopamine with controlled hydrophobic drug delivery ability and long-term bacteriostatic property. Colloid Polym Sci 2019. [DOI: 10.1007/s00396-019-04501-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Bahrpaima K, Fatehi P. Synthesis and Characterization of Carboxyethylated Lignosulfonate. CHEMSUSCHEM 2018; 11:2967-2980. [PMID: 29897668 DOI: 10.1002/cssc.201800994] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Indexed: 06/08/2023]
Abstract
Lignosulfonate is a byproduct of the sulfite pulping process and has limited use in industry. The main objective of this study was to investigate the carboxyethylation of lignosulfonate to increase its charge density to broaden its applications. The carboxyethylation of lignosulfonate was optimized under the conditions of 30 wt % NaOH, 2.0 mol mol-1 2-chloropropinic acid/lignosulfonate, 90 °C, 0.5 h, and 0.03 mol 2-chloropropinic acid, which produced carboxyethylated lignosulfonate with a charge density and molecular weight of -3.51 meq g-1 and 46 493 g mol-1 , respectively. The mechanism of the carboxyethylation reaction using 2-chloropropinic acid by an SN 1 pathway in an alkaline solution was discussed. Methylation was also used to mask the phenolic hydroxide groups of lignosulfonate to investigate if carboxyethylation occurred on aliphatic hydroxide groups of lignosulfonate. The produced carboxyethylated lignosulfonate was characterized by using FTIR spectroscopy, NMR spectroscopy, gel permeation chromatography, and elemental and functional group analyses. Basic 1 H-1 H 2 D COSY NMR spectroscopy was used to record the coupled spins of the carboxyethyl group on carboxyethylated lignosulfonate. The information from 1 D 1 H NMR and 2 D NMR COSY spectroscopy provided evidence for the existence of a 1-carboxyethyl group on the carboxyethylated lignosulfonate structure.
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Affiliation(s)
- Khatereh Bahrpaima
- Department of Chemistry, Firoozabad Branch, Islamic Azad University, Firoozabad, 74719-13113, Iran
- Department of Chemical Engineering, Lakehead University, Thunder Bay, ON, P7B 5E1, Canada
| | - Pedram Fatehi
- Department of Chemical Engineering, Lakehead University, Thunder Bay, ON, P7B 5E1, Canada
- State Key Laboratory of Paper Science, Technology of Ministry of Education, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China
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Liu J, Bacher M, Rosenau T, Willför S, Mihranyan A. Potentially Immunogenic Contaminants in Wood-Based and Bacterial Nanocellulose: Assessment of Endotoxin and (1,3)-β-d-Glucan Levels. Biomacromolecules 2017; 19:150-157. [PMID: 29182312 DOI: 10.1021/acs.biomac.7b01334] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Knowledge gaps in the biosafety data of the nanocellulose (NC) for biomedical use through various routes of administration call for closer look at health and exposure evaluation. This work evaluated the potentially immunogenic contaminants levels, for example, endotoxin and (1,3)-β-d-glucan, in four representative NCs, that is, wood-based NCs and bacterial cellulose (BC). The hot-water extracts were analyzed with ELISA assays, HPSEC-MALLS, GC, and NMR analysis. Varying levels of endotoxin and (1,3)-β-d-glucan contaminats were found in these widely used NCs. Although the β-(1,3)-d-glucan was not detected from the NMR spectra due to the small extract samples amount (2-7 mg), the anomerics and highly diastereotopic 6-CH2 signals may suggest the presence of β-(1,4)-linkages with β-(1,6) branching in the polysaccharides of NCs' hot-water extracts, which were otherwise not detectable in the enzymatic assay. In all, the article highlights the importance of monitoring various water-soluble potentially immunogenic contaminants in NC for biomedical use.
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Affiliation(s)
- Jun Liu
- Nanotechnology and Functional Materials, Department of Engineering Sciences, Box 534, Uppsala University , 75121 Uppsala, Sweden.,Biofuels Institute, School of the Environment and Safety Engineering, Jiangsu University , 212013 Zhenjiang, China
| | - Markus Bacher
- Department of Chemistry, University of Natural Resources and Applied Life Science (BOKU) , Muthgasse 18, 1190 Wien, Austria
| | - Thomas Rosenau
- Department of Chemistry, University of Natural Resources and Applied Life Science (BOKU) , Muthgasse 18, 1190 Wien, Austria.,Johan Gadolin Process Chemistry Centre, c/o Laboratory of Wood and Paper Chemistry, Åbo Akademi University , Porthansgatan 3-5, FI-20500, Turku/Åbo, Finland
| | - Stefan Willför
- Johan Gadolin Process Chemistry Centre, c/o Laboratory of Wood and Paper Chemistry, Åbo Akademi University , Porthansgatan 3-5, FI-20500, Turku/Åbo, Finland
| | - Albert Mihranyan
- Nanotechnology and Functional Materials, Department of Engineering Sciences, Box 534, Uppsala University , 75121 Uppsala, Sweden
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Kono H, Oka C, Kishimoto R, Fujita S. NMR characterization of cellulose acetate: Mole fraction of monomers in cellulose acetate determined from carbonyl carbon resonances. Carbohydr Polym 2017; 170:23-32. [DOI: 10.1016/j.carbpol.2017.04.061] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 04/03/2017] [Accepted: 04/21/2017] [Indexed: 12/19/2022]
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Kono H. Determination of mole fractions of ethyl-cellulose-containing monomers by NMR. Carbohydr Res 2017; 445:51-60. [PMID: 28402900 DOI: 10.1016/j.carres.2017.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 04/05/2017] [Indexed: 11/17/2022]
Abstract
Three samples of ethyl cellulose (EC) with different degrees of substitution (DS)-0.51, 1.41, and 2.28-were prepared by a slurry method using ethyl bromide as the etherification reagent. 1H-13C HSQC and HSQC-TOCSY NMR spectral analysis allowed for complete assignment of the 1H and 13C chemical shifts, respectively, of eight anhydroglucose units (AGUs) comprising EC chains-un-, 2-mono-, 3-mono-, 6-mono-, 2,3-di-, 2,6-di-, 3,6-di-, and 2,3,6-tri-substituted AGUs. In addition, the lineshape of the quantitative 13C NMR spectra of the three EC samples provided change in the mole fractions of these AGUs against DS, making it possible to estimate the reaction mechanism for the production of EC, elucidating reactivities of the hydroxyl groups at the 2, 3, and 6 positions of cellulose and interactions between the substituent groups within the same AGU and vicinal AGUs.
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Affiliation(s)
- Hiroyuki Kono
- Division of Applied Chemistry and Biochemistry, National Institute of Technology, Tomakomai College, Nishikioka 443, Tomakomai, Hokkaido, 059 1275, Japan.
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NMR characterization of methylcellulose: Chemical shift assignment and mole fraction of monomers in the polymer chains. Carbohydr Polym 2017; 157:728-738. [DOI: 10.1016/j.carbpol.2016.10.056] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 10/18/2016] [Accepted: 10/20/2016] [Indexed: 01/06/2023]
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