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甲壳素和壳聚糖作为天然生物高分子材料的研究进展 总被引:9,自引:0,他引:9
甲壳素是自然界中含量仅次于纤维素的天然高分子,壳聚糖是甲壳素脱乙酰化后带有阳离子的多糖.壳聚糖中的自由氨基以及它的高结晶性,使得它能溶于酸,而不溶于碱和绝大数的有机溶剂.同时壳聚糖具有无毒性、无刺激性、良好的生物相容性、生物可溶解性, 以及高的电荷密度,因而被作为一种新型的天然生物材料得到广泛应用.文章介绍了甲壳素和壳聚糖的结构和性质,综述分析了甲壳素和壳聚糖在制备微球和作为支架材料中的应用, 并总结了甲壳素和壳聚糖在这两个方面存在的问题和发展前景. 相似文献
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生物高分子液晶的新家族——甲壳素及其衍生物 总被引:11,自引:0,他引:11
讨论了生物高分子甲壳素及其衍生物形成液晶态的基本结构条件。简要介绍了为制备液晶性甲壳素衍生物所必须的一些主要的化学修饰途径。综述了十几年来甲壳素衍生物(主要是壳聚糖及其衍生物)液晶性的研究进展。介绍了甲壳素及其衍生物的液晶纺丝及其应用前景。指出甲壳素衍生物已成为纤维素之外生物高分子液晶的一个新的大家族。 相似文献
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一种新的液晶高分子——丁酸壳聚糖的合成与表征 总被引:18,自引:2,他引:18
甲壳素几乎不溶于任何溶剂,由于其脱乙酰化产物壳聚糖含自由氨基,能被酸质子化而溶解,所以壳聚糖的应用领域远多于甲壳素.但是壳聚糖也仅能溶于酸性介质中,并不能溶于纯水和普通有机溶剂,因而人们对甲壳素或壳聚糖进行各种化学改性[1,2],寻求溶解性更好尤其能溶于水的衍生物,以扩大其应用范围.本文按文献[2~4]方法合成了O-丁酰化壳聚糖(简称丁酸壳聚糖),首次报道它具有溶致液晶性. 相似文献
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羧甲基甲壳素水溶液等电点的测定 总被引:1,自引:0,他引:1
羧甲基甲壳素水溶液等电点的测定陈炳稔汤又文陈文森(华南师范大学化学系广州510631)自然界每年生物合成的甲壳素估计数十亿吨,是仅次于纤维素的天然高分子化合物,壳聚糖是由甲壳素经过脱乙酰化反应而得到的一种生物高分子[1,2]。与甲壳素相比,壳聚糖的溶... 相似文献
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碱量法测定壳聚糖中胺基方法的改进 总被引:31,自引:0,他引:31
甲壳素(chitin)是一种天然高分子化合物,化学名称为2—乙酰胺基—2—脱氧—β—D—葡糖的聚合体。甲壳素不溶于稀酸、稀碱,故又称不溶性甲壳素。甲壳素经浓碱处理,分子中的乙酰基逐渐水解脱除。当脱乙酰基达到一定程度时,可溶于稀酸形成胶体溶液,脱乙酰基甲壳素又称可溶性甲壳素或壳聚糖(chitosan)。壳聚糖中胺基含量与其溶解性能、粘度、离子交换能 相似文献
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甲壳素和壳聚糖是可再生的大分子生物质资源.由于分子内和分子间的强烈氢键作用,甲壳素和壳聚糖不能溶解在水或常规有机溶剂中,这极大地限制了其在诸多领域中的应用.离子液体作为一种新型绿色溶剂,对甲壳素和壳聚糖具有优良的溶解作用.本文综述了离子液体对甲壳素和壳聚糖的溶解性能和溶解机理,概述了均相溶液体系中纤维、膜、凝胶等材料的制备以及酰化、接枝共聚、交联、降解、希夫碱化等多种衍生化反应,总结了离子液体在甲壳素和壳聚糖化学研究中面临的挑战并对其进行了展望. 相似文献
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以蘑菇为原料提取甲壳素,并制备壳聚糖。通过滴定法测定由蘑菇制备的壳聚糖的脱乙酰度,用乌氏黏度计测定了比浓黏度,并研究了制备工艺中加热温度和碱处理时间对它们的影响,计算了其产率;对以蘑菇为原料制取的甲壳素、壳聚糖的结构通过红外光谱进行表征。结果表明,在碱处理时间为24h、加热温度为100℃的条件下有较高的脱乙酰度;比浓黏度随着碱处理时间的延长、加热温度的增加都呈下降的趋势;壳聚糖产率为1.69%。制取的甲壳素、壳聚糖的红外光谱图表明,甲壳素在蘑菇中主要是以α-构型存在,α-构型甲壳素在浓碱中经过脱乙酰后生成β-构型的壳聚糖。 相似文献
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Chitin has been extracted from Philippine blue swimming crab. The extracted chitin was subjected to thermo gravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis The degree of acetylation of the extracted chitin, derived from the X-ray diffraction intensity values of chitin characteristic peaks, revealed that the extracted chitin is purer than the commercially acquired high purity chitin. The extracted chitin was used to form polymer films at different formation conditions. Polymer films were also formed from commercially acquired chitin for comparison. It was shown that films prepared from the extracted chitin at different conditions have greater ultimate tensile strengths as compared to the commercially-available plastic film. Morphologies of the material surface and the fracture surface were investigated using the scanning electron microscope to identify stress concentration sites that contributed to the weakening of material under tensile loading. 相似文献
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Dr. Luísa C. R. Carvalho Fausto Queda Cátia V. Almeida Santos Dr. M. Manuel B. Marques 《化学:亚洲杂志》2016,11(24):3468-3481
Chitin and chitosan are attractive biopolymers with enormous structural possibilities for chemical modification, creating platforms for new chemical entities with a broad scope of applications, ranging from material science to medicine. During the last few years, incredible efforts have been dedicated to the regioselective modification of these biopolymers paving the way for improved properties and tailored activities. Herein, the most recent advances in chitin/chitosan regioselective modification, reaction conditions, selectivity, and the impact on its applications are highlighted. Moreover, the recent focus on chitooligosaccharides, their regioselective and chemoselective functionalization, as well as their role in biological studies, including molecular recognition with several biological targets are also covered. 相似文献
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Qi Chen Ji-Wei Zhang Lu-Lu Chen Jun Yang Xin-Ling Yang Yun Ling Qing Yang 《中国化学快报》2017,28(6):1232-1237
Chitin is a structural component of fungal cell walls but is absent in vertebrates,mammals,and humans.Chitin synthase is thus an attractive molecular target for developing fungicides.Based on the structure of its donor substrate,UDP-N-acetyl-glucosamine,as well as the modelled structure of the bacterial chitin synthase NodC,we designed a novel scaffold which was then further optimized into a series of chitin synthase inhibitors.The most potent inhibitor,compound 13,exhibited high chitin synthase inhibitory activity with an IC_(50) value of 64.5 μmol/L All of the inhibitors exhibited antifungal activities against the growth of agriculturally-destructive fungi,Fusarium graminearum,Botrytis cinerea.and Colletotrichum lagenarium.This work presents a new scaffold which can be used for the development of novel fungicides. 相似文献
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Physicochemical characterization of α‐chitin, β‐chitin,and γ‐chitin separated from natural resources
Mi‐Kyeong Jang Byeong‐Gi Kong Young‐Il Jeong Chang Hyung Lee Jae‐Woon Nah 《Journal of polymer science. Part A, Polymer chemistry》2004,42(14):3423-3432
We isolated α‐chitin, β‐chitin, and γ‐chitin from natural resources by a chemical method to investigate the crystalline structure of chitin. Its characteristics were identified with Fourier transform infrared (FTIR) and solid‐state cross‐polarization/magic‐angle‐spinning (CP–MAS) 13C NMR spectrophotometers. The average molecular weights of α‐chitin, β‐chitin, and γ‐chitin, calculated with the relative viscosity, were about 701, 612, and 524 kDa, respectively. In the FTIR spectra, α‐chitin, β‐chitin, and γ‐chitin showed a doublet, a singlet, and a semidoublet at the amide I band, respectively. The solid‐state CP–MAS 13C NMR spectra revealed that α‐chitin was sharply resolved around 73 and 75 ppm and that β‐chitin had a singlet around 74 ppm. For γ‐chitin, two signals appeared around 73 and 75 ppm. From the X‐ray diffraction results, α‐chitin was observed to have four crystalline reflections at 9.6, 19.6, 21.1, and 23.7 by the crystalline structure. Also, β‐chitin was observed to have two crystalline reflections at 9.1 and 20.3 by the crystalline structure. γ‐Chitin, having an antiparallel and parallel structure, was similar in its X‐ray diffraction patterns to α‐chitin. The exothermic peaks of α‐chitin, β‐chitin, and γ‐chitin appeared at 330, 230, and 310, respectively. The thermal decomposition activation energies of α‐chitin, β‐chitin, and γ‐chitin, calculated by thermogravimetric analysis, were 60.56, 58.16, and 59.26 kJ mol?1, respectively. With the Arrhenius law, ln β was plotted against the reciprocal of the maximum decomposition temperature as a straight line; there was a large slope for large activation energies and a small slope for small activation energies. α‐Chitin with high activation energies was very temperature‐sensitive; β‐Chitin with low activation energies was relatively temperature‐insensitive. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3423–3432, 2004 相似文献
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Prof. Pedro Laborda Yong-Mei Lyu Dr. Fabio Parmeggiani Dr. Ai-Min Lu Wen-Jiao Wang Ying-Ying Huang Dr. Kun Huang Juan Guo Prof. Li Liu Prof. Sabine L. Flitsch Prof. Josef Voglmeir 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(13):5346-5349
Chitin is one of the most abundant and cheaply available biopolymers in Nature. Chitin has become a valuable starting material for many biotechnological products through manipulation of its N-acetyl functionality, which can be cleaved under mild conditions using the enzyme family of de-N-acetylases. However, the chemoselective enzymatic re-acylation of glucosamine derivatives, which can introduce new stable functionalities into chitin derivatives, is much less explored. Herein we describe an acylase (CmCDA from Cyclobacterium marinum) that catalyzes the N-acylation of glycosamine with a range of carboxylic acids under physiological reaction conditions. This biocatalyst closes an important gap in allowing the conversion of chitin into complex glycosides, such as C5-modified sialosides, through the use of highly selective enzyme cascades. 相似文献
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Pedro Laborda Yong‐Mei Lyu Fabio Parmeggiani Ai‐Min Lu Wen‐Jiao Wang Ying‐Ying Huang Kun Huang Juan Guo Li Liu Sabine L. Flitsch Josef Voglmeir 《Angewandte Chemie (International ed. in English)》2020,59(13):5308-5311
Chitin is one of the most abundant and cheaply available biopolymers in Nature. Chitin has become a valuable starting material for many biotechnological products through manipulation of its N‐acetyl functionality, which can be cleaved under mild conditions using the enzyme family of de‐N‐acetylases. However, the chemoselective enzymatic re‐acylation of glucosamine derivatives, which can introduce new stable functionalities into chitin derivatives, is much less explored. Herein we describe an acylase (CmCDA from Cyclobacterium marinum) that catalyzes the N‐acylation of glycosamine with a range of carboxylic acids under physiological reaction conditions. This biocatalyst closes an important gap in allowing the conversion of chitin into complex glycosides, such as C5‐modified sialosides, through the use of highly selective enzyme cascades. 相似文献
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Hideaki Nagahama Nitar New Rangasamy Jayakumar Tetsuya Furuike Hiroshi Tamura 《Macromolecular Symposia》2008,264(1):8-12
Chitin, a natural abundant polysaccharide, have been investigated as prospected biochemical material due to its several biological advantages. It is insoluble in the most of the organic solvents due to its rigid crystalline structure. However, chitin regenerated hydrogel (RG) has been prepared by using the saturated calcium solvent system under mild conditions. And also, swelling hydrogel (SG) was prepared by using water. In this study, we prepared the suspension of chitinous hydrogel, and applied to fabricated the chitinous compound/gelatin composite sheets. Additionally, N-acetyl D-(+)-glucosamine was added into some composite sheets. We investigated the mechanical properties and growth of NIH/3T3 fibroblast cell for the prepared composite sheet. 相似文献
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Seiichi Tokura Shin-Ichiro Nishimura Nobuo Sakairi Norio Nishi 《Macromolecular Symposia》1996,101(1):389-396
A low toxicity of chitin was demonstrated to be mostly due to biodegradability and the fast metabolization of hydrolysate in animal body. Chitosan, a deacetylated derivative of chitin, is also known to be a biocompatible polymer in spite of a slight immunoadjuvant activity in animal body. Chitosan is easily regenerated to fiber, film, beads and non woven fabrics owing to its high solubility toward diluted aqueous organic acids such as formic acid, acetic acid, glutamic acid and ascorbic acid. The regeneration of chitin was achieved into fibers, gels, porous foams and non woven fabrics following to dissolution of chitin with formic acid or calcium chloride dihydrate saturated methanol. Chitin and its derivatives have been applied as biomedical materials due to remarkable advantages such as antimicrobial activity, acceleration of epidermal cell assembly, low toxicity, and biodegradability. 相似文献