以乙二醛为交联剂的壳聚糖纤维交联机理探索

采用乙二醛为交联剂对壳聚糖纤维进行交联处理以改善纤维强度。基于对红外光谱和核磁共振图谱的分析,探索了乙二醛与壳聚糖纤维交联反应的机理。研究结果表明,乙二醛特殊的化学结构使其利于亲核试剂的攻击,而壳聚糖的氨基和羟基具有亲核性,因此乙二醛可以与壳聚糖发生交联反应。交联反应主要有两类:一类是发生在壳聚糖C2氨基与乙二醛羰基之间的Schiff碱反应,占据主导地位;另一类是发生在壳聚糖C6羟基与乙二醛羰基之间的缩醛化反应,处于次要地位。     

Visible light-induced photocurable (forming a film) low molecular weight chitosan derivatives for biomedical applications: Synthesis,characterization and in vitro biocompatibility

In this work, visible light-induced photocurable low molecular weight chitosan derivatives (F-LMC: furfuryl-low molecular weight chitosan) were prepared by nitrous acid decomposition followed by modification with furfuryl glycidyl ether. The structure of the decomposition products (LMC: low molecular weight chitosan) was characterized by FT-IR analysis. The structure and molecular weight of F-LMC, prepared from the decomposition products by modification with furfuryl glycidyl ether, were characterized by ¹H NMR and GPC analysis, respectively. F-LMC was initially water-soluble, but after the exposure to visible light, it became water-insoluble, indicating that F-LMC undergoes visible light-induced inter- and intra-molecular cross-linking. The cross-linking was determined by concentration of F-LMC and time of exposure to visible light. The cytotoxicity test using fibroblast 3T3 showed no toxicity of F-LMC. Cross-linked F-LMC surface inhibited cell adherence.     

烷基化壳聚糖的制备及载药膜的释放行为研究

用不同碳链长度的卤代烷与壳聚糖反应制成N－烷基化壳聚糖。红外和X－射线衍射结果表明壳聚糖引入烷基基团后分子间氢键和结晶度受到削弱。采用氧化葡萄糖作交联剂，测定了不同pH条件下烷基化壳聚糖膜对维生素B2的渗透系数，并考察了该交联膜的细胞毒性，结果表明该膜无细胞毒性。     

Sorption of acid dyes onto GLA and H2SO4 cross-linked chitosan beads

The feasibility of chitosan and cross-linked chitosan beads as efficient adsorbents for the removal of Acid Blue 25 (AB 25) and Acid Red 37 (AR 37) from aqueous solution was studied by using batch adsorption techniques. Glutaraldehyde (GLA) and sulphuric acid were employed as cross-linking reagents. The effect of process parameters like pH, agitation period, agitation rate and concentrations of dyes on the extent of AR 37 and AB 25 adsorption by chitosan and cross-linked chitosan beads was investigated. The best interpretation for the equilibrium data was given by the Langmuir isotherm, while the pseudo-second-order kinetic model could best describe the adsorption of these acid dyes. Thermodynamic parameters such as enthalpy change (ΔH°), free energy change (ΔG°) and entropy change (ΔS°) were estimated and adsorption process was spontaneous and exothermic. The desorbed chitosan, chitosan-GLA and chitosan-H₂SO₄ beads can be reused to adsorb the acid dyes. Results also showed that chitosan, chitosan-GLA and chitosan-H₂SO₄ beads were favourable adsorbers.     

微球型壳聚糖胺基吸附剂的制备及性能

以壳聚糖为原料,采用反相悬浮交联的方法制取微球型壳聚糖颗粒,再进行羟丙基氯化及胺基化,制备了一系列新型壳聚糖胺基衍生物微球。衍生物的胺基含量明显提高,碱性增强。并初步考察其吸附牛血清白蛋白（ＢＳＡ）性能。可用作新固定化酶载体及生化分离材料。     

N-辛基-O-聚乙二醇壳聚糖衍生物的制备与表征

以自然界富有的天然壳聚糖为原料,在其分子结构的2位—NH2上引入部分疏水性辛基,并对其余的—NH2进行有效保护;然后在3,6位的—OH上引入亲水性聚乙二醇基团,合成了具有两亲性的N-辛基-O-聚乙二醇壳聚糖衍生物。通过FTIR,1HNMR和元素分析对衍生物的分子结构和N-位、O-位取代度进行了表征。该壳聚糖衍生物具有两亲性,水溶性好,且分子结构中保留了可用于后续交联反应的活性—NH2,在制备两亲性壳聚糖微球型药物载体领域具有潜在的应用价值。     

Investigation on Conjugation Capacity of New Chitosan Carriers Based on Conjugated Model Toward Enzyme Delivery

In this work, for the first time, the authors report their observations on cross-linking condition, and its effects on conjugation capacity of a bioactive model. Therefore, carriers of chitosan films and microspheres were produced by using glutaraldehyde as bifunctional cross-linking agent. The following stages were carried out: preparation of cross-linked chitosan films and microspheres, conjugation of drug model on films and microspheres, investigation on the properties of the synthesized carriers and finally enzyme immobilization studies. Based on our results, degree of cross-linking and drug conjugation capacity, as two important factors, affect simultaneously the thermal, morphological, and hydrolytic behavior of the carriers in film and microsphere forms. From the experimental data, with increasing the degree of cross-linking and drug conjugation capacity, the drug release was increased up to 12% w/w of glutaraldehyde; however, on further increasing the degree of cross-linking (18% w/w), the drug released in a burst manner. Also, regarding to the results from drug and enzyme conjugates, it is possible to design diversity of the chitosan derivatives based on different degree of cross-linking as well as enzyme conjugation capacity as reliable carriers.     

Preparation of oxidized 6-O-glycolchitosan,pH sensitivity of its aqueous solution and of its cross-linked hydrogel

Chitosan and 6-O-glycolchitosan, a water-soluble chitosan derivative, were oxidized by periodate. In the case of chitosan, only degradation products were obtained. With 6-O-glycolchitosan, however, water-soluble amphoteric polyelectrolyte derivatives of chitosan having higher molecular weight were obtained. The oxidized 6-O-glycolchitosan (OX-GC) showed a pH sensitive change of viscosity in aqueous solution. Moreover, the OX-GC hydrogel, cross-linked with glutaraldehyde, showed a pH sensitive swelling behavior. The OX-GC showed biodegradation behavior by lysozyme after acetylation.     

羟丙基壳聚糖/氧化甲基纤维素自愈合水凝胶的制备及其载药性能

采用高碘酸钠对甲基纤维素（MC）进行氧化制备了氧化甲基纤维素（DAMC），通过羟丙基壳聚糖（HPC）的氨基与DAMC的醛基发生希夫碱反应制备了HPC/DAMC自愈合水凝胶。通过调节HPC和DAMC含量探究水凝胶的微观形态、溶胀性能、力学性能、自愈合性能、体外降解以及药物缓释性能。结果表明，HPC/DAMC自愈合水凝胶具有相互连通的孔隙，且孔径处于80～375μm范围内，在室温无刺激条件下能够在20 min内实现自愈合且具有良好的拉伸性能。此外，HPC/DAMC自愈合水凝胶具有良好的保水性，其溶胀比为14.0～17.4。在溶菌酶的作用下，HPC/DAMC自愈合水凝胶在60 h时质量损失率可达84.2%～99.6%。HPC/DAMC自愈合水凝胶对抗肿瘤药物吉西他滨具有缓释效果，缓释作用长达96 h，药物累积释放率达到83.2%～92.7%。     

壳聚糖基壁材在精油/鱼油微胶囊化方面的应用进展

微胶囊化可以提高精油/鱼油的抗氧化性、储存稳定性和生物活性以及改善其气味。具有良好生物相容性、成膜性和渗透性的壳聚糖及其衍生物成为制备微胶囊的理想壁材。本文以壳聚糖基壁材为主线,结合不同成囊机理和方法对精油/鱼油微胶囊制备研究进展进行综述。重点介绍了不同种类壳聚糖壁材（普通壳聚糖、壳聚糖复合物及壳聚糖衍生物）和成囊方法（如喷雾干燥法、单凝聚法、复凝聚法、交联法以及层层自组装法等）的优缺点。分析表明,改进成囊方法控制粒径和提高油包埋率;探寻无毒、高效的囊膜交联剂控制释放效率;合成新型的壳聚糖衍生物壁材提高功能性质,是壳聚糖基壁材包囊精油/鱼油的重要研究方向。     

T型微通道装置制备尺寸均一壳聚糖微球

采用T型微通道装置制备尺寸均一的壳聚糖微球. 研究了乳化剂用量、油水两相流速比和流速等条件对乳液粒径的影响,尝试制备了不同分子量的壳聚糖乳液,并确定了交联固化方式. T型微通道装置的油相通道直径350 mm,水相通道直径65 mm,两通道接口处直径16 mm. 以1.5%(w)的壳聚糖醋酸水溶液为水相,以液体石蜡/石油醚(7/5, j)的混合物作为油相,水相流速20 mL/min,油水两相流速比为15:1,4%(w)的PO-500作为油相乳化剂,制备得到的壳聚糖乳液粒径分布系数<10%. 以戊二醛的甲苯溶液作为交联剂,当戊二醛所含醛基与壳聚糖所含氨基的摩尔比为1:1时,交联时间选择2 h.     

KMnO4氧化法冷制淀粉胶

在酸性环境中，常温下用KMnO4制得氧化淀粉，再配以适当的催干剂、交联剂、掩蔽剂等制成淀粉胶粘剂，可有效地提高干燥速度，同时，解决了存在的KMnO4氧化胶颜色较深问题。     

Effect of Nanoclay Content and pH of the Medium on the Swelling Characteristics of Grafted and Cross-Linked Mixed Chitosan Derivatives

A mixture of chitosan and carboxy methyl chitosan along with silane functionalized nanoclay has been grafted with acrylic acid followed by cross-linking. The nanocomposites were then examined for swelling characteristics in acidic, alkaline and neutral medium. In all the three mediums, an optimal clay content with maximum swelling was observed. The thermal characterization of the nanocomposites was also carried out.     

基于饮用水除氟的改性壳聚糖制备技术研究进展

在众多的除氟技术中,吸附法是最常用的方法。壳聚糖以其无毒、易降解、廉价易得等优点,成为制备新型除氟剂的理想材料。综述了交联壳聚糖、羧甲基壳聚糖、壳聚糖/稀土配合物、过渡金属改性壳聚糖等衍生物的制备方法、机理及其对水中氟离子的吸附效果,并对今后的研究方向进行了展望。     

新型水溶性壳聚糖衍生物的制备

以醋酸和丙酮为反应介质,利用马来酸酐在均相条件下对壳聚糖进行水溶性N-酰化改性;与壳聚糖相比,改性后的壳聚糖衍生物的水溶性有了很大改善。实验表明：对壳聚糖的N-酰化改性程度越高,其改性产物的水溶性越好;同时,制备的3种样品的产率均在90％以上。     

O-二酸单酯-N,N双长链烷基壳寡糖的制备及表征

壳寡糖与月桂醛反应生成Schiff碱,再用NaBH4还原合成N,N-双十二烷基化壳寡糖,然后在均相条件下与酸酐反应制备了含有不同亲水基团的新型双亲性壳寡糖衍生物:O-丁烯二酸单酯-N,N-双十二烷基壳寡糖(OBDCS)、O-丁二酸单酯-N,N-双十二烷基壳寡糖(OSDCS)和O-邻苯二甲酸单酯-N,N-双十二烷基壳寡糖(OPDCS)。用红外光谱、核磁共振和元素分析等方法对产物的结构进行了表征,并试验了其溶解性能。结果表明,改性产物的溶解性能明显优于未改性的N,N-双十二烷基壳寡糖,拓宽了壳寡糖的应用范围。     

Preparation of water‐soluble chitosan derivatives and their antibacterial activity

Carboxymethyl chitosan sodium (CMCTS) was synthesized by chitosan and chloroacetic acid under an alkali catalyst. Acrylic acid sodium salt and methylacrylic acid sodium salt were grafted onto CMCTS to obtain copolymers with good water solubility. The graft reaction was carried out at 70°C for 2 h, and ammonium persulfate was used as an initiator. The structure changes of chitosan and its derivatives were investigated by the FTIR. The antibacterial activity of chitosan derivatives against Staphylococcus aureus and Escherichia coli were explored by the viable cell counting method. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1357–1361, 2002     

阿司匹林-壳聚糖缓释微球的制备和释药性能研究

采用乳化交联法制备阿司匹林-壳聚糖缓释凝胶微球,通过透析实验检测微球的体外释放特性。应用正交实验设计,考察了壳聚糖浓度,搅拌速度,阿司匹林/壳聚糖质量比,交联时间对微球制备的影响。体外释放实验表明,壳聚糖微球前5个小时的释放符合SRP的释药行为。以5个小时的体外释放总量为指标进行直观分析,交联时间对5小时的体外释放总量影响最大。     

壳聚糖酰胺衍生物保湿性能研究

壳聚糖具有良好的保湿性能 ,但由于不溶于水 ,因此在化妆品中难以应用。虽然它能溶于酸溶液中 ,但会发生降解而不稳定。壳聚糖可与生物有机酸反应制得壳聚糖N -酰化的衍生物 ,2 %的该类衍生物 ,其保湿性明显优于10 %的甘油水溶液 ,而且粘度稳定 ,无降解发生 ,故可在化妆品中用作保湿剂。     

戊二醛与甲醛交联壳聚糖微球的比较研究

壳聚糖微球是肥料和农药的重要缓释载体之一。根据相关实验数据及文献显示,纯的壳聚糖成球性能差,易溶解,需要加入一定的交联剂、乳化剂和致孔剂对其进行交联改性,改善微球的性能。分别采用戊二醛、甲醛两种交联剂,通过乳化-化学交联方法制备壳聚糖微球。通过扫描电子显微镜对壳聚糖微球表面、内部结构及形态特征进行观察,测量壳聚糖微球粒径的大小。采用红外光谱(FT-IR)以及交联度测试对两种交联微球进行了对比。结果表明:以戊二醛为交联剂所制得的壳聚糖微球各个方面性能均优于以甲醛为交联剂所制得的壳聚糖微球。