多糖的改性、表征及应用研究

【作者】 吴刚；

【导师】 沈玉华；

【作者基本信息】 安徽大学 ， 无机化学， 2003， 硕士

【摘要】 本文将壳聚糖改性，进行羧甲基化，制取了水溶性的羧甲基壳聚糖，并研究了其水溶液的性质；研究了羧甲基壳聚糖和壳聚糖对胆红素的吸附性能和影响其吸附性能的因素；研究了单独羧甲基壳聚糖、葡聚糖作为模板、十八胺／十八酸单分子膜作为模板，羧甲基壳聚糖和碳酸钙过饱和溶液作为亚相诱导生成的碳酸钙的晶型等。其主要内容如下： 1．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，成功制备了取代度为1.84、平均分子量为3.08 10~5的可溶性N,O-羧甲基壳聚糖(CMC)。分别用红外光谱、紫外光谱、荧光光谱对其结构进行了表征。CMC紫外光谱在206nm处有最大吸收，这是羧基中电子的n-~*跃迁所致；CMC荧光激发波长为330nm，荧光最大发射波长为407nm，与壳聚糖相比，发生了变化。 研究了CMC水溶液的一些物理化学性质。发现其表面张力随着浓度的增加几乎成线性降低，说明CMC具有表面活性；其溶液的电导率随浓度的增加成线性增加；浓度降低，其水溶液的Zeta电位值增加，在水溶液中，CMC存在一定程度的聚集。CMC为两性聚电解质，等电点为7.28。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CMC微粒的粒径分布进行了研究。介质的pH值和浓度对CMC溶液的稳定性有很大的影响。 2．壳聚糖、CMC对胆红素吸附性能的研究 以具有良好生物相容性的壳聚糖和CMC为吸附剂，研究了温度、pH值、人血清白蛋白和NaCl对壳聚糖、CMC吸附胆红素性能的影响。研究结果表明：在实验温度范围内，由于升高温度提高了分子的运动速度和提高了壳聚糖、CMC的溶涨度，因此升高温度可提高壳聚糖、CMC吸附胆红素的吸附率和吸附速率；pH值对壳聚糖、CMC吸附胆红素的吸附率和吸附速率有较大的影响，低pH值有利于壳聚糖、CMC对胆红素吸附；加入NaCl时，增加了溶液的离子强度，由于降低了胆红素的活度，降低了壳聚糖、CMC对胆红素的吸附速率和吸附率；人血清白蛋白可以和胆红素结合成为更大的分子，使得分子体积增大，同时也降低了胆红素分子的热运动速度，因此人血清白蛋白的存在可降低壳聚糖、CMC 女回大学申请顾1：学位论文 摘要 对胆红素的吸附速率和吸附率，但总体来讲，在接近人体血液pH值和温度的条 件下，壳聚糖、CMC对胆红素有良好的吸附性能。 3．较甲基壳聚糖对十八胺／十八酸单分子膜诱导碳酸钙晶型的影响 研究表明，以十八胺／十八酸作为单分子膜，以碳酸钙过饱和溶液为亚相能 诱导生成方解石型碳酸钙晶体，以CMC／碳酸钙饱和溶液为亚相，诱导生成的碳 酸钙晶型与CMC的浓度有关，随着亚相中CMC浓度的增加，碳酸钙由主要为 方解石型晶体逐渐变为文石和球霞石型晶体，说明CMC参与诱导和控制碳酸钙 晶体的生成。 4．按甲基壳聚糖对碳酸钙晶型的影响 研究认为，碳酸钙和装甲基壳聚糖分子中羟基、波基之间存在配位作用，这 种配位作用为碳酸钙结晶提供了成核位点，降低了异相成核活化能，促进了碳酸 钙晶体的异相成核。同时拉甲基壳聚糖的表面活性和在一定的浓度范围内对碳酸 钙晶粒的包裹所起到的保护作用，使得碳酸钙纳米粒子可以稳定地存在于水相 中。 碳酸钙的成核结晶除了受到上述的局域化学影响外，其晶型还受到驻甲基壳 聚糖的控制。装甲基壳聚糖分子为碳酸钙的成核提供了一个有组织的界面，在这 个界面上，功能性基团间距和晶核立体结构相互匹配，在碳酸钙晶体的生成过程 中起到模板作用，诱导生成了高能量的球霞石。 5．葡聚糖体系中诱导碳酸钙晶体生长的研究 研究认为，葡聚糖分子的羟基和Ca’”离子存在配位作用，此配位点成为碳酸 钙结晶的成核位点。在葡聚糖溶液中葡聚糖诱导生成了方解石型CaCO。纳米微 粒，这是因为葡聚糖分子在较高浓度时自组装成网状结构，而在浓度较稀时组装 成线形超分子结构，这两种结构都有利于能量较低的方解石型晶体的生成。研 究中同时发现，钙离子和葡聚糖的羟基和人血清白蛋白分子中的联基、氮原子存 在配位作用，葡聚糖溶液中加入的人血清白蛋白可能改变了葡聚糖的组装方式， 诱导生成的碳酸钙晶体形状与葡聚糖诱导的形状不同，由菱形变成椭球形。更多还原

【Abstract】 1.we synthesized N,O-Carboxymethylchitosan(CMC) beginning with chitosan and chloracetic acid by stepwisely increasing temperature method. CMC substitutive degree is 1.84, average molecular weight is 3.08x 105 and instrinic viscosity [ ] (25 0.5 ) is 180L/g, It was characterized by ultraviolet pectrum, infrared spectrum, fluorescence spectrum. Its ultraviolet characteristic absorption peak is at 206 nm arising form n- ’electron transition. However, The ultraviolet characteristic absorption peak of chitosan is at 195 nm. One of stretching vibration absorption peak of CMC infrared spectrum is at 1635cm-1 which results from stretching vibration of- C=0(-COOH)Bond.But at 1635cm-1 there is no stretching vibration peak of- C=0 in the chitosan infrared spectrum.In fluorescence spectrum, Excitation wavelength of CMC is 330nm and its emission wavelength is 407nm. Excitation wavelength of Chitosan is 320nm and its emission wavelength is 391nm.CMC synthesized is soluable in the aqueous solution.It is a macromolecular surface-active agent. CMC surface tension linearly decreases with the increasing of CMC concentration in aqueous solution.But its conductivity linearly increases with the increasing of CMC concentration in aqueous solution.The work also studied the CMC aggregate behaviours in CMC aqueous solution,which showed that there is some degree aggregation in the aqueous solution of CMC.Meanwhile ,the work studied th Zeta potential of CMC aqueous solution.It demonstrates that Zeta potential volue decreases with the decreasing of the concentration of CMC.The study found CMC is a amphoteric macromecleular electrolyte and its isoelectronic point is 7.28.Therefore,the pH volue and concentration of CMC have great influence on stability of CMC aqueous solution.2.The influence of temperature, pH value, human serum albumin (HAS) and ionic intensity on chitosan and CMC’ s adsorbability for bilirubin was studied. Chitosan, CMC chitosan, CMC can be used as the blood adsorbent because of their good biologic compatibility. The result showed that HAS and NaCl could preventfrom the adsorption of chitosan CMC for bilirubin. In the given temperature range, raising temperature could fasten adsorptivity velocity and enhance adsorbability of chitosan and CMC. Being closed to pH value of blood in human body, the chitosan has the good adsorbability for the uncombined bilirubin.3. calcium carbonate was synethsized by CMC inducing between interface of octadecanamine/stearic acid mixed monolayer molecule film and subphase of calcium carbonate, CaCO3 /CMC saturated aqueous solution,respectively.The appearance of calcium carbonate synthesized was observed by SEM.In the subphase of water(pH=8.6), calcium carbonate, CaCO3/CMC saturated aqueous solution, the behaviours of monolayer molecule film of octadecanamine/stearic acid were studied.lt shows that CMC can be adsorbed under the monolayer molecule film of octadecanamine/stearic acid.SEM pictures indicate that crystal kind of calcium carbonate formed under film is calcite by monolayer molecule film inducing when the subphase is CaCO3 saturated aqueous solution.The kinds of calcium carbonate crystal are relate to the concentration of CMC when the subphase is CMC/CaCO3 saturated aqueous solution.With the increasing of CMC concentration,the calcium carbonate crystal type formed under the film varied from calcite,to vaterite,to aragonite.lt demonstrates that CMC can cantrol the crystallographic orientation of calcium carbonate crystal.4.the simulation biomineralization of calcium carbonate was carried out in the CMC aqeous solution.The conclusion that there is coordination reaction between the hydroxyls , carboxyls of CMC molecules and calcium carbonate can be concluded from ultraviolet pectrum, infrared spectrum. This coordination reaction taked place on the organized structure surface of CMC molecules,which provide nucleation site for calcium carbonate crystal.This action decreases active energy of nucleation of calcium carbonate crystal.So it boosts更多还原