甲壳素及其衍生物的研究与应用

甲壳素是自然界中仅次于纤维素大量存在的高分子化合物。近年来,甲壳素及其衍生物的研究十分活跃。研究内容涉及甲壳素的资源、甲壳素及壳聚糖的提取、纯化、分析方法、结构测定以及甲壳素在众多领域中的应用。大量的研究结果表明,甲壳素及其衍生物具有成膜性、抗凝血性、促进伤口愈合、防腐抗菌、促进农作物生长以及螯合与吸附等功能。因而在食品、生化、医药、日用化妆品及污水处理等许多工业领域具有日益广泛的用途。1甲壳素的结构甲壳素学名为［（1,4）-2-乙酰胺基-2-脱氧-β-D-葡聚糖］,广泛存在于虾、蟹壳中,同时也大量存在于真…     

不同脱乙酰度壳聚糖接枝丙烯酰胺的合成与表征

从甲壳素出发，先制备了3种不同脱乙酰度的壳聚糖，选择过硫酸铵-亚硫酸氢钠为氧化还原体系引发剂，合成了壳聚糖接枝丙烯酰胺聚合物；通过红外光谱，电镜扫描对聚合物进行结构表征，结果表明壳聚糖结构发生了变化，通过在相同条件下比较壳聚糖不同脱乙酰度对接枝率的影响，得出了在脱乙酰度为68．5％时聚合物的接枝率最大为250％，其最佳合成工艺为：m（壳聚糖）：m（丙烯酰胺）=1：5，引发剂用量为体系质量分数的0．3％～0．4％，温度55～60℃，反应时间为2．5～3．0h。     

不同脱乙酰度壳聚糖接枝丙烯酰胺的合成与表征(英文)

从甲壳素出发,先制备了3种不同脱乙酰度的壳聚糖,选择过硫酸铵_亚硫酸氢钠为氧化还原体系引发剂,合成了壳聚糖接枝丙烯酰胺聚合物;通过红外光谱,电镜扫描对聚合物进行结构表征,结果表明壳聚糖结构发生了变化,通过在相同条件下比较壳聚糖不同脱乙酰度对接枝率的影响,得出了在脱乙酰度为68.5%时聚合物的接枝率最大为250%,其最佳合成工艺为∶m(壳聚糖)∶m(丙烯酰胺)=1∶5,引发剂用量为体系质量分数的0.3%~0.4%,温度55~60℃,反应时间为2.5~3.0 h。     

壳聚糖希夫碱铜配合物的制备及其催化性能

采用微波辐射加热法使壳聚糖与水杨醛反应生成壳聚糖希夫碱。然后将其与铜盐配位得到壳聚糖希夫碱铜配合物。用UV、FTIR、TG表征产物的结构，并探讨该配合物对过氧化氢分解的催化性能。研究结果表明：壳聚糖希夫碱铜配合物对过氧化氢有良好的催化活性。常温（25℃）常压．pH=7．0的条件下放置12h,催化H2O2的分解达99．8％。该配合物重复使用3次还保持较好的催化活性。     

制备条件对聚乙烯醇-壳聚糖凝胶性能的影响

以戊二醛为交联剂,由聚乙烯醇(PVA)和壳聚糖(CTS)混合交联得到一种水凝胶,考察了聚乙烯醇和壳聚糖的配比、交联剂用量和反应时间对聚乙烯醇/壳聚糖凝胶吸水率的影响。通过单因素实验,得出了聚乙烯醇/壳聚糖凝胶具有最佳溶胀性能时的条件:聚乙烯醇与壳聚糖的摩尔比为6∶1,交联剂戊二醛的体积分数为0.05%,反应时间9h。测定了该凝胶在不同pH值下的吸水率和吸附铜离子的性能,得出聚乙烯醇/壳聚糖凝胶在酸性介质的吸水率远远大于碱性介质,对铜离子(Cu2+)的吸附量比壳聚糖凝胶提高了33.7%,因此该凝胶吸附剂在工业废水处理重金属离子方面具有一定的优越性。     

湿热处理对壳聚糖／PVA共混膜结构和性能的影响

用流延法成功制备壳聚糖／PVA共混膜．并进行湿热处理，用FT—IR、XRD对经过湿热处理，七混膜进行了裘征，测试了膜的力学性能和吸水性；结果表明，随着湿热处理时间的增长共混膜的无水结晶峰出现并不断增强。共混膜的吸水性实验表明，壳聚糖／PVA共混膜的pH敏感性可通过控制湿热处理的时间来改变．由于湿热处理不需要引入诸如戊二醛等对生物有毒副作用的化学交联剂，所以该法可望在壳聚糖／PvA共混膜控释体系的后处理方面得到应用。     

壳聚糖对腐生葡萄球菌的作用机制

【目的】探究壳聚糖处理对腐生葡萄球菌(Staphylococcus saprophytic)的作用机制。【方法】通过光密度值结合菌液澄清度法综合确定壳聚糖对腐生葡萄球菌的最小抑菌浓度(Minimum Inhibitory Concentration,MIC),分析其在MIC与2MIC的壳聚糖作用下的微生物生长曲线、电导率值、碱性磷酸酶(Alkaline Phosphatase,AKP)含量、过氧化氢酶(Catalase,CAT)含量、苹果酸脱氢酶(Malatedehydrogenase,MDH)含量与生物膜生成量等指标变化,并结合扫描电镜(ScanningElectronMicroscopy,SEM)观察其作用后对菌体细胞形态变化影响,综合评价壳聚糖处理对腐生葡萄球菌的作用机制。【结果与结论】壳聚糖对腐生葡萄球菌的MIC为1.25 mg/mL;菌体经MIC和2MIC处理后,其正常生长受到抑制,细胞壁被破坏,细胞膜通透性改变,CAT与MDH含量降低,其作用效果与壳聚糖浓度正相关;SEM结果显示,与对照CK组对比,腐生葡萄球菌经MIC壳聚糖处理后,菌体形状不规则,表面皱褶;经2MIC壳聚糖处理后,菌体表面产生泡状物且黏附明显,表明壳聚糖使腐生葡萄球菌菌体细胞壁受损,菌体生长受到抑制,胞内保护酶与三羧酸循环中的关键酶活性降低,细胞代谢能力随之下降,细胞膜结构完整度受到破坏,最终导致菌体死亡。     

壳聚糖生产工艺的优选研究

用正交试验等方法优选过聚糖生产中胶钙，脱蛋白质，脱乙酰基等工序的工艺条件。试验结果表明；用体积分数为３％的ＨＣｌ脱钙１５ｈ可使制品的灰分含量〈１％；用质量分数为８％的ＮａＯＨ煮沸９０ｍｉｎ脱蛋白质，可使制品总氮含量〈７％；在碱质量分数为４２％，物料与碱液配比为１：４０，８０℃保温１８ｈ的条件下、制品粘度〉２００ｍＰａ．ｓ脱乙酰度〉８０％。     

Preparation and in vitro Release Performance of Sustained-release Captopril/Chitosan-gelatin Net-polymer Microspheres

The captopril/Chitosan-gelatin net-polymer microspheres(CTP/CGNPMs) were prepared using Chitosan(CTS) and gelatin(GT) by the methods of emulsification,cross-linked reagent alone or in combination and microcrystalline cellulose(MCC) added in the process of preparation of microspheres,which aimed to eliminate dose dumping and burst phenomenon of microspheres for the improvement of the therapeutic efficiency and the decrease of the side effects of captopril(CTP). The results indicated that CTP/CGNPMs had a spherical shape,smooth surface and integral structure inside but no adhesive phenomena in the preparation. The size distribution ranged from 220 μm to 280 μm. The CTP release test in vitro demonstrated that CTP/CGNPMs played the role of retarding the release of CTP compared with ordinary CTP tablets. The release behaviors of CGNPMS were influenced by preparation conditions such as experimental material ratio(EMR) and composition of cross linking reagents. Among these factors,the EMR(1/4),CLR(FA SPP) and 0.75% microcrystalline cellulose(MCC) added to the microspheres constituted the optimal scheme for the preparation of CTP/CGNPMs. The ER,DL and SR of CTP/CGNPMs prepared according to the optimal scheme were 46.23±4.51%,9.95±0.77% and 261±42%,respectively. The CTP/CGNPMs had the good characteristics of sustained release of drug and the process of emulsification and cross-linking were simple and stable. The CGNPMs are likely to be an ideal sustained release formulation for water-soluble drugs.     

Preparations,characterizations and applications of chitosan-based nanoparticles

Chitosan is a natural polysaccharide prepared by the N-deacetylation of chitin. In this paper we have reviewed the methods of preparation of chitosan-based nanoparticles and their pharmaceutical applications. There are five methods of their preparations： emulsion cross-linking, emulsion-droplet coalescence, ionic gelation, reverse micellar method and chemically modified chitosan method. Chitosan nanoparticles are used as carriers for low molecular weight drug, vaccines and DNA. Releasing characteristics, biodistribution and applications are also summarized.     

新型壳聚糖季铵盐衍生物的合成与表征

采用甲磺酸作为溶剂兼作氨基保护试剂,对壳聚糖上的羟基选择性酯化,再游离出氨基并对其氯乙酰化,最后进行吡啶成盐,得到新型水溶性的壳聚糖季铵盐衍生物,产物的结构通过核磁共振氢谱和红外光谱进行了表征,从而为壳聚糖季铵盐衍生物的制备提供了一种新途径。     

酶法在低聚壳聚糖制备上的研究现状及展望

甲壳素(chitin)广泛存在于虾、蟹等甲壳动物,部分植物,细菌及真菌等生物中,是仅次于纤维素的第二大类天然高分子化合物,年平均产量达数十亿吨之多[1]。壳聚糖(chtiosan)是甲壳素脱乙酰化产物,是膳食纤维中唯一的一种含有阳离子的高分子基团[2]。甲壳素及壳聚糖具有很多优越的特性,但由于溶解性较差,影响了它在各行业中的应用。为了改善壳聚糖的溶解性以及一些医学、保健性质,对其各种衍生物及壳聚糖低聚物的研究已逐渐展开[3,4]。甲壳素及壳聚糖的低聚物是指聚合度低于10的一些低聚葡聚糖,这些多糖具有优越的水溶性、保湿性。另外,D-低聚葡…     

Effects of sulfate chitosan derivatives on nonalcoholic fatty liver disease

Sulfate chitosan derivatives have good solubility and therapeutic effect on the cell model of NAFLD. The aim of this study was to examine the therapeutic effect of sulfate chitosan derivatives on NAFLD. The male Wistar rats were orally fed high fat emulsion and received sulfate chitosan derivatives for 5 weeks to determine the pre-treatment effect of sulfate chitosan derivatives on NAFLD. To evaluate the therapeutic effect of sulfate chitosan derivatives on NAFLD, the rats were orally fed with high concentration emulsion for 5 weeks, followed by sulfate chitosan derivatives for 3 weeks. Histological analysis and biomedical assays showed that sulfate chitosan derivatives can dramatically prevent the development of hepatic steatosis in hepatocyte cells. In animal studies, pre-treatment and treatment with sulfate chitosan derivatives significantly protected against hepatic steatohepatitis induced by high fat diet according to histological analysis. Furthermore, increased TC, ALT, MDA, and LEP in NAFLD were significantly ameliorated by pre-treatment and treatment with sulfate chitosan derivatives. Furthermore, increased TG, AST, and TNF-α in NAFLD were significantly ameliorated by treatment with sulfate chitosan derivatives. Sulfate chitosan derivatives have good pre-treatment and therapeutic effect on NAFLD.     

壳聚糖生产工艺的优选研究

用正交试验等方法优选壳聚糖生产中脱钙、脱蛋白质、脱乙酸基等工序的工艺条件。试验结果表明：用体积分数为3％的HCl脱钙15h可使制品的灰分含量＜1％；用质量分数为8％的NaOH煮沸90min脱蛋白质，可使制品总氮含量＜7％；在碱质量分数为42％、物料与碱液配比为1∶40、80℃保温18h的条件下，制品粘度＞2000mPa．s．脱乙酰度＞80％。     

壳聚糖希夫碱铜配合物的制备及其催化性能

采用微波辐射加热法使壳聚糖与水杨醛反应生成壳聚糖希夫碱,然后将其与铜盐配位得到壳聚糖希夫碱铜配合物,用UV、FTIR、TG表征产物的结构,并探讨该配合物对过氧化氢分解的催化性能。研究结果表明:壳聚糖希夫碱铜配合物对过氧化氢有良好的催化活性,常温(25℃)常压,pH=7.0的条件下放置12 h,催化H2O2的分解达99.8%,该配合物重复使用3次还保持较好的催化活性。     

混合分子质量壳聚糖结合臭氧杀菌处理对罗非鱼片的冷藏保鲜作用

以感官评分、细菌总数、pH、挥发性盐基氮(TVB-N)等作为其保鲜效果的评价指标,研究混合分子质量的壳聚糖结合臭氧杀菌处理对罗非鱼片4℃冷藏保鲜效果的影响。结果表明:混合分子质量壳聚糖结合臭氧水杀菌处理能减少罗非鱼片的菌落总数并抑制细菌的生长繁殖,减缓pH的变化,保持罗非鱼片的感官品质,延缓TVB-N值的升高,延长罗非鱼片的保鲜期,其保鲜效果优于单一分子质量的壳聚糖。     

湿热处理对壳聚糖/PVA共混膜结构和性能的影响

用流延法成功制备壳聚糖/PVA共混膜,并进行湿热处理,用FT-IR、XRD对经过湿热处理共混膜进行了表征,测试了膜的力学性能和吸水性;结果表明,随着湿热处理时间的增长共混膜的无水结晶峰出现并不断增强。共混膜的吸水性实验表明,壳聚糖/PVA共混膜的pH敏感性可通过控制湿热处理的时间来改变,由于湿热处理不需要引入诸如戊二醛等对生物有毒副作用的化学交联剂,所以该法可望在壳聚糖/PVA共混膜控释体系的后处理方面得到应用。     

Preparation and charaterization of self-assembled nanoparticles based on linolenic-acid modified chitosan

1 IntroductionHydrophobically modified water-soluble polymers,also known as hydrophobized polymers, are thosemodified by hydrophobic groups such as alkyl,arolkyl, and deoxycholic acid. In water, they canself-aggregate due to their intro- and/or intermolecularhydrophobic interaction. By this process, unique hy-drogel nanoparticles with hydrophobic core and hy-drophilic shell can be prepared, which is a new ap-proach to preparing the monodispersed hydrogelnanoparticles (Whitesides et al., 1991; …     

羟基红花黄色素A-壳聚糖微球制备工艺研究

为探究羟基红花黄色素A-结合壳聚糖(HSYA-CS)微球的最佳制备工艺,采用乳化交联法制备,以微球的表观特征、粒径分布、包封率及载药量作为主要的评价指标,通过单因素考察和正交试验优化微球的最佳制备工艺。结果表明:戊二醛用量2.0 mL、交联温度50℃、投药比1∶5时,所制备的微球大小比较均一,黏连程度小,圆整度高,粒径范围2.0～4.6μm,载药量(6.53±0.42)%,包封率(68.04±0.46)%,正交设计证实上述条件下制备工艺最佳;乳化交联法制备HSYA-CS微球工艺方法稳定可行,产品性状较好,载药量和包封率较高,可为HSYA的临床应用效果的优化提供方法学借鉴。