羧甲基壳聚糖阻垢缓蚀性能研究

本文以两种不同分子量的壳聚糖为原材制备了一系列不同分子量不同羧甲基取代度的羧甲基壳聚糖(CMCS),通过静态阻垢法、扫描电子显微镜(SEM)、X射线衍射(XRD)、失重法、极化曲线法、电化学阻抗法等技术详细考察了CMCS内部结构因素(分子量、羧甲基取代度等)与外部环境因素(药剂投加量、温度等)对碳酸钙的阻垢以及对碳钢的缓蚀性能影响.结果表明CMCS具有较好的缓蚀阻垢效果. CMCS的阻垢与缓蚀性能均随着羧甲基取代度的增加而增强;在相似羧甲基取代度条件下,分子量低的壳聚糖制得的CMCS的阻垢及缓蚀效果更佳. SEM和XRD结果分析表明, CMCS作为阻垢剂对CaCO_3的阻垢作用是晶格畸变、螯合作用和分散增容作用等多种效应共同作用的结果.在CMCS缓蚀机制研究中,失重法及电化学法结果大体一致, CMCS是一种混合型缓蚀剂,能同时抑制阴极和阳极反应;抑制机理主要是CMCS上羟基、氨基及羧基等活性功能基团上孤对电子易与Fe外层空轨道有效配位形成单分子层保护膜,从而隔绝腐蚀介质达到对碳钢缓蚀的目的.综上, CMCS具有较好的阻垢缓蚀效果,其作为一种绿色环保的水处理剂材料,具有广阔的应用前景.     

新型羧甲基壳聚糖水凝胶流变性能,药物释放及细胞相容性研究

羧甲基壳聚糖含有丰富的羧基和氨基, 通过1-乙基-(3-二甲基氨基丙基)碳二亚胺盐酸盐(EDC)和N-羟基琥珀酰亚胺(NHS)共催化交联羧甲基壳聚糖形成新型水凝胶. 调节EDC/NHS用量, 制备不同交联度的羧甲基壳聚糖水凝胶(CMCS hydrogels). 研究水凝胶的流变行为, 结果表明, 高交联度的水凝胶具有较好的弹性形变能力, 较高的储存模量, 这是因为随着交联度的升高, 羧甲基壳聚糖水凝胶化学交联网络结构趋于完善. 以胸腺五肽(TP-5)为模型药物, 初步评价CMCS水凝胶药物释放行为, 结果表明水凝胶交联度越高, 胸腺五肽释放速度越慢. MTT法初步评价了水凝胶细胞毒性, 细胞形态和细胞相对增值速率, 结果表明水凝胶毒性很低. 由此可见, 水凝胶具有良好的生物相容性, 在药物缓释和组织工程领域具有广阔的应用前景.     

羧甲基壳聚糖与钙离子络合作用的研究

羧甲基壳聚糖(carboxymethyl chitosan,CMCS)是壳聚糖Chitosan经化学改性得到的水溶性衍生物,由于羧基的引入,络合金属离子的能力及反应速度大大提高[1-6],在医药、化工、环保等领域有着广泛的应用前景。本文研究了羧甲基壳聚糖与Ca2 络合的条件,着重探讨了Pb2 在不同条件下对络合反应的影响,以期扩大羧甲基壳聚糖的应用范围。1材料与方法1.1仪器与试剂羧甲基壳聚糖(自制),其它试剂均为国产优级纯。TAS-986G原子吸收分光光度计;SX5-12箱式电阻炉;GL-20B高速冷冻离心机;Ori-on818型pH测试计。1.2实验方法1.2.1羧甲基壳聚糖与Ca2 络合…     

N,O-羧甲基壳聚糖的合成和性质研究

采用多段升温法将壳聚糖改性,合成了取代度为1.84、平均分子量为3.08×105、等电点为7.28的N,O-羧甲基壳聚糖(CMC),分别用紫外光谱、红外光谱、荧光光谱对其结构进行了表征,并对其水溶液的Zeta电位、电导率、表面张力以及水分散体系中羧甲基壳聚糖微粒的粒径分布进行了研究.结果表明, N,O-羧甲基壳聚糖具有表面活性;介质的pH值和浓度对羧甲基壳聚糖溶液的稳定性有很大的影响.     

萘酞菁锌复合体系的光致电荷转移

合成了萘酞菁锌, 利用傅立叶红外光谱、元素分析和MALDI-TOF质谱等手段表征了分子结构; 循环伏安测试和吸收光谱确认了共轭体系的扩大使分子带隙下降. 根据材料加工性能的不同, 分别采用溶液法、层-层蒸镀(Layer-by-layer evaporation)法和单层分散旋涂法, 将给体分子萘酞菁锌与三种受体分子1-(3-甲氧基羧基)丙基-1-苯 基-[6,6]C61, C60和N,N’-二嘧啶基苝四羧基二酰亚胺进行了复合, 通过研究复合前后荧光变化, 确认了给体-受体两相界面处发生了由分子能级差引发的光致电荷转移, 为制备更宽光伏响应范围的太阳能电池器件提供了潜在的新途径.     

O-羧甲基-N-琥珀酰壳聚糖对Cu~(2+)的吸附研究

以壳聚糖为原料,先制备O-羧甲基壳聚糖,再与琥珀酸酐水溶剂反应合成出O-羧甲基-N-琥珀酰壳聚糖衍生物,采用1H-NMR、FT-IR和TG表征其结构。系统研究了O-羧甲基-N-琥珀酰壳聚糖对水溶液中Cu~(2+)的吸附性能,主要考察了溶液的p H值、温度、吸附时间等因素对吸附的影响及吸附热力学性能。结果表明,O-羧甲基-N-琥珀酰壳聚糖对Cu2+平衡吸附量达到133.5mg/g,动力学符合准二级动力学模型,对Cu~(2+)的吸附符合Freundlich等温吸附模型。红外表明,吸附主要依靠分子结构中的羧基和氨基。     

羧甲基壳聚糖-Cu(Ⅱ)配合物的制备及其表征

制备了不同摩尔比的羧甲基壳聚糖-铜配合物,运用红外光谱、紫外吸收光谱、循环伏安法、差热-热重分析等手段对配合物进行了结构性能表征。结果表明,羧甲基壳聚糖中的羧基和氨基参与了与Cu2+的配位,生成的羧甲基壳聚糖-铜配合物具有电化学活性,其热稳定性较羧甲基壳聚糖降低。     

天然高分子电场敏感水凝胶——大豆蛋白/羧甲基壳聚糖体系

通过将大豆蛋白(SPI)和羧甲基壳聚糖(CMCS)进行溶液共混,并加入环氧氯丙烷作为交联剂,成功制备了一种天然高分子两性荷电水凝胶.这种SPI/CMCS水凝胶在电场的作用下可以快速弯向一侧电极,表现出很好的电场敏感性.由于该水凝胶具有两性荷电的特性,因此其在不同pH值的电解质溶液中既可以弯向阳极(当pH6时),也可以弯向阴极(当pH6时).除了pH的变化,其他诸如施加电压的大小以及水凝胶的厚度也会对SPI/CMCS水凝胶在电场中的行为产生影响.相比于先前报道的另外两种天然高分子电场敏感水凝胶,即壳聚糖/羧甲基纤维素水凝胶和壳聚糖/羧甲基壳聚糖水凝胶,SPI/CMCS水凝胶在酸性较强(pH=3～4)以及中性(pH=7)的环境中仍能表现出良好的电场敏感性,拓展了天然高分子电场敏感水凝胶的应用范围.     

羧甲基壳聚糖磁性纳米粒子的合成及应用

通过合成油酸修饰的Fe3O4纳米粒子和羧甲基壳聚糖直接包埋油酸修饰的Fe3O4纳米粒子的两步合成法制备了羧甲基壳聚糖磁性纳米粒子。采用透射电子显微镜、傅里叶变换红外光谱、振动样品磁强计和同步热分析测试技术对制备的羧甲基壳聚糖磁性纳米粒子进行了表征。所得磁性纳米粒子呈规则球形,粒径约为10 nm;表面含羧基,且具有很好的顺磁性和稳定性。考察了羧甲基壳聚糖磁性纳米粒子对阿霉素的载药量和对阿霉素在磷酸盐缓冲溶液中的缓释性能。结果表明,磁性纳米粒子对阿霉素展示了较高的载药量(91.8 mg/g),结合了阿霉素的磁性复合物对阿霉素的缓释作用明显,说明制备的羧甲基壳聚糖磁性纳米粒子有望作为治疗肿瘤的纳米磁靶向药物输送载体。     

原位交联羧甲基壳聚糖/碳酸钙凝胶海绵的制备及其止血性能研究

以羧甲基壳聚糖(CMCS)、碳酸钙(CaCO₃)、葡萄糖酸内酯(GDL)和甘油(GLY)为原料，通过原位相转变制备水凝胶，经冷冻干燥工艺得到止血海绵，用于躯体非压迫性出血。通过扫描电镜、吸水率、孔隙率、溶血实验和全血凝固时间测试分别对海绵的理化性能、血液安全性、止血性能进行研究。当CaCO₃与CMCS的质量比为15%时，制得的海绵综合性能最好。该海绵呈疏松多孔片层状，止血时间较医用棉纱布材料缩短了35%,无血液毒性，是一种优良的止血海绵材料。     

Petunia-shaped superstructures of CaCO3 aggregates modulated by modified chitosan

This paper presents the crystallization behavior of calcium carbonate at the air/liquid interface of aqueous systems of carboxymethyl chitosan (CMCS) using the Kitano method. Although the synthesized CMCS (Mw approximately 100,000) with 1.57 degree of carboxymethyl substitution shows no surface activity, it controls the crystallization of calcium carbonate to form a petunia-shaped superstructure. The shuttlecock-like head of this superstructure strongly supports Colfen's opinion (Rudloff, J.; Colfen, H. Langmuir 2004, 20, 991-996) for the existence of a gas template of CO2 bubbles temporarily captured by polymer molecules, while formation of the stem of this superstructure is provisionally attributed to the presence of the strong electrostatic interactions between calcium ions and the carboxylate groups. The CaCO3 superstructure and its morphology depend not only on the polymer concentration but also on the combined number of calcium ions per CMCS molecule. These results imply that this simple and versatile method expands the morphological investigation of mineralization processes.     

Antimicrobial activity of new carboxymethyl chitosan–carbon nanotube biocomposites and their swell ability in different pH media

New carboxymethyl chitosan–carbon nanotube (CMCS-CNT) biocomposites were prepared and characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and normal photography. The recorded images of the CMCS-CNT biocomposites showed homogeneous distribution of carbon nanotubes into the carboxymethyl chitosan (CMCS) matrix. Their antimicrobial activity and swell ability in different pH media have been investigated. They showed a higher antimicrobial activity against tested gram-positive and gram-negative bacteria. The inhibition zone diameters are closer to that recorded for the commonly used antibiotics. They showed an increase in the swell ability in different pH media relative to the parent CMCS. It would be expected that these nanobiocomposites are promising candidates for medical applications.     

Studies on Adsorption Property for Metal Ions of Carboxymethyl Chitosan

Chitosan is a polymer, which contains β-1, 4-linked α-amino-2-deoxy-D-glucopyranose repeat units and is easily derived from chitin by N-deacetylation. Since chitosan is biodegradable, relatively nontoxic, nonimmunogenic, much research has been directed toward its use in medical applications^[1].It also has been suggested for use as chelating agent for metals, since the primary amino group and hydroxyl functionalities at the ring^[2]. Chitosan is only soluble in aqueous solution of some acids, so it becomes a limitation. The carboxymethyl chitosan (CMCS),a water-soluble derivative of chitosan, was synthesized by chemical modification with ClCH₂COOH and chitosan^[3]. It was amphoteric polyelectolyte with stronger chelating ability for metals because of introduction of-COOH.     

Synthesis and characterization of novel carboxymethyl chitosan grafted polylactide hydrogels for controlled drug delivery

Novel carboxymethyl chitosan‐polylactide (CMCS‐g‐PLA) hydrogels were prepared by using 1‐(3‐dimethylaminopropyl)‐3‐ethylcarbodiimide hydrochloride/N‐hydroxysuccinimide (EDC/NHS) as crosslinking agent and catalyst at room temperature. Solid‐state ¹³C‐NMR, SEM, and FT‐IR measurements showed that PLA blocks are successfully grafted onto the CMCS main chains. DSC measurements confirmed the effective crosslinking of carboxymethyl chitosan. With increasing the amount of EDC/NHS, the crosslink destiny of CMCS‐g‐PLA copolymers is improved. The swelling ratio of CMCS‐g‐PLA hydrogels is pH dependent, showing a minimum in the pH range of 3 to 5. Rheological studies confirmed the formation of hydrogels. The higher the crosslinking density, the higher the storage modulus of hydrogels. CMCS‐g‐PLA hydrogels only slightly degrade in PBS for 10 days. In the presence of lysozyme, however, hydrogels with low crosslink density are totally degraded in 10 days. Drug release studies show that after 96 h, 95% of thymopentin is released under in vitro conditions. Copyright © 2015 John Wiley & Sons, Ltd.     

3-N-乙酰基-2-取代芳基-5-[5''-甲基-异噁唑-3'']-Δ3-1,3,4－噁唑啉类化合物的合成

保护氨基的壳聚糖微球经环氧氯丙烷交联得到不溶于酸的吸附剂，与氯乙酸在碱性条件下反应，合成了羧甲基壳聚糖树脂，并用FT-IR对树脂进行了表征。其吸附Pb^2 的实验结果表明，在1h内有最快的吸附速率，吸附受pH值影响。在pH=5时，对Pb^2 的吸附量为1．12mmol／g，比壳聚糖树脂提高了70％。     

Properties of water-soluble carboxymethyl chitosan film modified by hydrophobic poly(propylene glycol)

A series of water-soluble carboxymethyl chitosan (CMCS)/poly(propylene glycol) (PPG) blend films with various CMCS/PPG mole ratios were prepared by the solution casting method. Morphology of the CMCS/PPG blend films was investigated by scanning electron microscopy (SEM). Thermal, mechanical, and chemical properties of the CMCS/PPG blend films were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), tensile tests, and contact angle tests. It was found that the introduction of PPG can markedly affect the morphology and the properties of CMCS films.     

Stimuli-responsive multilayer chitosan hollow microspheres via layer-by-layer assembly

Novel stimuli-responsive multilayer chitosan hollow microspheres with chitosan as the unique component have been fabricated by the sequential layer-by-layer electrostatic assembly technique from the sacrificial templates (polystyrene sulfonate, PSS) with chitosan (CS) as the polycation and carboxymethyl chitosan (CMCS) as the polyanion, respectively. Their hollow structure was confirmed by the TEM analysis. The DLS analysis indicated that the multilayer chitosan microcapsules were pH and ionic strength dual-responsive. Due to the biocompatibility of the single component chitosan used, the multilayer chitosan microcapsules are expected to be used in the controlled release of drugs.     

Dissociation behaviors of carboxyl and amine groups on carboxymethyl‐chitosan in aqueous system

Several carboxymethyl‐chitosan (CMCS) samples with different deacetylation degree and/or substituted degree were prepared from the carboxymethylation reaction of chitosan under soft conditions. The products were dissolved in standard HCl aqueous solution to carry out potentiometric titration by using NaOH as titrating solution at different ionic strengths. Then the dissociation behaviors of protonated carboxyl and amine groups were investigated under their degree of dissociation (α) and protonation constant (pK_α) had been calculated. Moreover, influences of the intrinsic and extrinsic parameters on the dissociation behavior of CMCS were also considered in this article. As a result, dissociations of carboxyl and amine on CMCS exhibited unusual behaviors in comparison with carboxyl of carboxymethyl‐cellulose and amine groups of chitosan, respectively. The pK_α values of carboxyl declined slightly at early dissociation stage but subsequently maintained constant. In contrast, the pK_α of ammonium increased with its dissociation degree despite that there was an inflexed change on its dissociation curve. The potentiometric behavior of carboxyl was hardly affected by variation of deacetylation degree or substituted degree. However, these intrinsic parameters played more important role on dissociations of ammonium on CMCS. The ionic strength of media could bring screening effect on dissociaciation of both sorts of ionizable groups of CMCS. By increasing the ionic strength of media, screening effect on dissociations increased significantly. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1419–1429, 2008     

Self-aggregated nanoparticles from linoleic acid modified carboxymethyl chitosan: Synthesis, characterization and application in vitro

The purpose of the present research work was to study the formation of linoleic acid (LA) modified carboxymethyl chitosan (LCC). Another objective was to evaluate effect of linoleic acid degree of substitution on loading capacity (LC), ADR loading efficiency (LE) and in vitro release profile of LCC nanoparticles. The hydrogel nanoparticles can be prepared using linoleic acid modified carboxymethyl chitosan (LACMCS) after the sonication. The critical aggregation concentration (CAC) of the self-aggregate of LA modified CMCS (LCC) was determined by measuring the fluorescence intensity of the pyrene as a fluorescent probe. The CAC values were in the range of 0.061–0.081 mg/mL. Self-aggregated nanoparticles exhibited an increased LC and LE, decreased sustained release with an increasing ratio of the hydrophobic LA to hydrophilic CMCS. LCC nanoparticles loaded with ADR exerted in vitro anticancer activity against Hela cells that was comparable to the activity of free (non-entrapped in nanoparticles) ADR.