N,N-双十二烷基壳聚糖/胆固醇混合单分子膜及自组装囊泡性质

研究了添加胆固醇对N,N-双十二烷基壳聚糖(N,N-dilauryl chitosan, DLCS)单分子膜以及自组装囊泡性质的影响. 结果表明, 引入少量胆固醇会导致DLCS膜的凝聚性下降; 当胆固醇含量增加到一定程度后, 混合膜的凝聚性增强. 添加胆固醇可显著改变DLCS载药囊泡的药物释放行为, 少量胆固醇可以提高载药囊泡的释放速率和平衡药物释放百分率; 而较高含量胆固醇则可抑制囊泡的释放速率和降低平衡药物释放百分率. 此外, 囊泡平衡药物释放率与其单分子膜压缩模量呈现一定线性关系, 这说明胆固醇的引入导致囊泡分子膜凝聚性的改变, 从而改变囊泡的通透性. 通过调节胆固醇的加入量, 可以制得药物释放行为在一定范围内可控的自组装囊泡.     

电容法研究卵磷脂/氨基酸/H_2O胶束和囊泡体系

运用电容法研究卵磷脂/氨基酸/H2O胶束和囊泡体系结构与性质.卵磷脂的临界胶束浓度和囊泡生成浓度可由体系电容-卵磷脂浓度关系曲线求得.随着卵磷脂浓度增加,体系电容增加,卵磷脂由胶束形成囊泡.随着氨基酸浓度增加,胶束、囊泡半径增大,体系电容减小.氨基酸能促进卵磷脂形成胶束和囊泡,使得卵磷脂临界胶束浓度和囊泡生成浓度减小,其影响的强弱顺序为组氨酸色氨酸垌甘氨酸.     

不含蛋白质的功能泡囊膜及对酶的模拟

本篇综述了模拟生物膜的不含蛋白质的功能泡囊膜的建立过程,并介绍了这类功能泡囊膜所进行的模拟酶的泡囊催化反应。以磷脂或亲水亲油的表面活性剂分子所提供的双分子层泡囊结构为基质,分别在其不同的区域引入活性基团或分子,赋予了泡囊新的功能,由此可实现对一些反应的进程及产物构象的控制。利用这类功能泡囊膜,已成功地模拟了水解酶、还原酶、转氨酶、生物体内的碳单元传递反应等,并为模拟光合作用提供了一个很好的模式。     

电容法研究卵磷脂/氨基酸/H2O胶束和囊泡体系

运用电容法研究卵磷脂/氨基酸/H2O胶束和囊泡体系结构与性质. 卵磷脂的临界胶束浓度和囊泡生成浓度可由体系电容-卵磷脂浓度关系曲线求得.随着卵磷脂浓度增加, 体系电容增加, 卵磷脂由胶束形成囊泡. 随着氨基酸浓度增加, 胶束、囊泡半径增大, 体系电容减小. 氨基酸能促进卵磷脂形成胶束和囊泡, 使得卵磷脂临界胶束浓度和囊泡生成浓度减小, 其影响的强弱顺序为组氨酸>色氨酸>>甘氨酸.     

季铵盐型Gemini表面活性剂诱导囊泡结构改变机理研究

用动态光散射技术以及荧光探针方法, 研究了不同连接基长度的季铵盐型Gemini表面活性剂对卵磷脂囊泡结构改变的影响, 并借助理论模型和临界堆积参数理论探索了Gemini表面活性剂诱导囊泡结构改变的机理. 实验结果表明, 表面活性剂诱导囊泡结构改变的主要原因是表面活性剂嵌入到囊泡的双分子层中, 从而改变了囊泡的表面电荷强度以及嵌入后的表面活性剂在囊泡双分子层中分布的不均匀性. 此外, 表面活性剂分子的结构也会对其产生影响, 不同连接基长度的季铵盐型Gemini表面活性剂对囊泡结构改变的影响不完全相同, 但会呈现出一定的规律性.     

囊泡的形成与两亲分子结构

本文综述了可以形成囊泡的各类两亲分子的结构特点和形成条件，并对某些体系中囊泡的形成机理进行了探讨。     

胆固醇对卵磷脂有序体中生成CaCO3晶型的影响

报道了在卵磷脂、胆固醇、橄榄油、电解质溶液组成的分子有序组合体中,胆固醇的加入影响了有序体的膜结构、表面特性,从而也影响到有序体微环境中所生成的CaCO₃晶体结构。随着胆固醇含量增加,在一定范围内球霰石的相对含量增大;油包水体系中生成的球霰石相对含量远大于水包油体系中生成的球霰石相对含量。     

卵磷脂-水-油酸体系液晶对胆固醇的增溶作用

Formation and structure of liquid crystal in lecithin-water-oleic acid system were studied. It was found that different from the lecithin-water system, there are two types of liquid crystal present. The lamellar liquid crystal was formed at lower content of oleic acid, the values of interlayer spacing are larger than the values in the corresponding liquid crystal without oleic acid. The inverse hexangonal liquid crysta1 was formed at higher content of oleic acid. In lecithin-water-oleic acid(containing 15℅ cholesterol) system the phase behavior of liquid crystal is similar to that in the lecithin-water-oleic acid system. The solubilization rate of solid cholesterol in lamellar liquid crystal of lecithin-water-oleic acid system is more faster than that of lecithin-water system.     

Al3+离子对卵磷脂聚集体结构的影响

本文用浊度滴定(UV-Vis)、透射电镜(TEM)和激光光散射(QELS)等方法对Al³⁺离子与卵磷脂(EYPC)囊泡之间的相互作用及其这种相互作用对溶液中磷脂微结构的影响进行了研究。结果表明，一定量的Al³⁺离子使EYPC多层囊泡转变为线团状聚集体;Al³⁺与牛磺胆酸钠(TC)的协同作用可以破坏EYPC的多层囊泡结构，促进相转变，形成混合胶束。     

原子力显微镜研究囊泡在云母表面形成的结构

The vesicle structures of egg yolks phosphatidylcholine/didodecyldimethylammonium bromide （1 ： 1, mass ratio） deposited on mica were studied by atomic force microscopy （AFM） both in aqueous phase and air. In aqueous phase both bilayer and domelike vesicles with a mean diameter of 45 nm were observed, whereas in air the structure was more complicated depending on the initial concentration of vesicles. Vesicles with the original size could only be visualized at very low concentration with a mean diameter of 55 nm, which is a little larger than the result obtained in aqueous phase. At higher concentrations, fused large aggregates and multiple bilayer with a thickness ca. 4 nm of each bilayer were dominated. A plausible adsorption mechanism was proposed based on the experimental results.     

高分子微泡体系中光解水的研究：（Ⅱ）聚卵磷脂微泡在光解水中的应用

本文研究以卵磷脂为单体形成的微泡体系,以Co~(60)辐照为聚合方式,通过超声波作用将联吡啶钌和EDTA,甲基紫精和铂溶胶等光解水的试剂置于微泡的不同区域,从而获得不同的光解水效果。     

Chronoamperometric Determination of Lecithin

Abstract

A rapid, sensitive and reproducible chronoarnperometric method for the determination of lecithin is described. The method is based on the inhibition of the oxygen reduction process by the adsorption of lecithin at the mercury -solution interface. Current-time curves recorded during the growth of single mercury drops at ?0.200 V (vs SCE) in aqueous-ethanolic solutions of lecithin are employed. The adsorption effect may be evaluated by measuring the time necessary for a complete drop surface coverage, “t_o”, interpolating the descending branch of the i-t curves linearly to zero current. The influence of the variables that affect the inhibition process is studied and a linear relationship between t^1/2 _o and lecithin concentration in the 20–80 μg/ml range is found. The relative standard deviation of the proposed method is 1.3%.     

高分子微泡的研究——Ⅰ.二烯丙基二(十二烷基)季铵盐的合成与聚合

本文合成了二烯丙基二(十二烷基)溴化铵(DADD),用超声波分散其水溶液而形成微泡。用γ射线、偶氮二异丁睛(AIBN)、过硫酸铵(APS)引发使微泡发生聚合,井对所得的微泡进行表征。实验结果证明:用γ射线引发能使微泡双分子膜发生全部聚合、而用AIBN,APS引发则只能发生部分聚合,聚合后,微泡的形状(态),渗透性行为、相转变温度等都未发生变化,但其稳定性却提高了,用断裂电镜证实了本文所合成的微泡是单室的双分子膜微泡。     

磷酸盐缓冲体系中大豆卵磷脂的分析

建立了一种测定磷酸盐缓冲体系中大豆卵磷脂含量的方法。利用无水乙醇－石油醚（６０～９０℃）萃取剂从磷酸盐缓冲溶液中分离出大豆卵磷脂，再用钼蓝法对大豆卵磷脂含量进行测定。该方法操作简便，定量准确，重现性好，用于胰岛素口腔喷剂中大豆卵磷脂含量测定，样品平均回收率为９９．７５％，ＲＳＤ＝３．９３％。     

The Quantitation of Lecithin,Sphingomyelin and Their Ratios by Infrared Spectroscopy

Abstract

We describe a new method for measuring lecithin and its ratio to sphingomyelin with the use of infrared spectrophotometry. The method offers quantitation of lecithin, and sphingomyelin and their ratios, in approximately two hours, without the use of thin layer chromatography. Once the extraction of phospholipids is completed, an infrared spectral scan from 4000 to 400 (cm′) is obtained from which two peaks are measured and quantitated for lecithin and sphingomyelin and their ratios.     

脂质体-纳米粒与单个巨型囊泡相互作用的理论模拟

采用自洽平均场方法模拟了脂质体-纳米粒与巨型囊泡的相互作用.在初始状态,脂质体-纳米粒与巨型囊泡之间有一定距离,随着距离的变化,脂质体-纳米粒与囊泡发生相互作用,最终脂质体小囊泡和巨型囊泡会融合并使粒子释放.随着囊泡的磷脂分子组分的变化,体系呈现出丰富的结构变化.磷脂头体积分数较大时体系形成融合通道(stalk相)或半融合隔膜(HD相)以及融合小孔;磷脂头体积分数较小时体系出现囊泡的渗漏形成亲水聚集体(棒状HII相或IMI相)和融合小孔.改变了所包裹的纳米粒半径,发现对体系的结构影响不大.我们定量的计算了各个体系的自由能,从自由能分析可知,随着距离的减小,脂质体-纳米粒与巨型囊泡相互作用的过程是一个自发过程.在相互作用过程中,新结构的形成需要克服能量壁垒,且能量壁垒随着磷脂头体积分数和纳米粒半径的增大都会有一定程度的增加.     

基于蛋白质直接电子转移的全胆固醇传感器

以壳聚糖为载体, 将血红蛋白、胆固醇氧化酶及胆固醇酯酶固定在玻碳电极表面, 在不使用任何电子媒介体的条件下, 利用血红蛋白和电极之间的直接电子转移, 制备出高选择性的全胆固醇生物传感器, 并用于测定血清中总胆固醇含量. 利用循环伏安法和恒电位法研究了该传感器的电化学特性. 在优化的实验条件下, 该传感器对胆固醇响应的线性范围为10~110 mg/dL, 检出限为5 mg/dL(信噪比的3倍), 响应时间为60 s. 对人血清中总胆固醇的测定表明, RSD小于6.2%, 回收率为95%~106%.     

纳米电极-膜片钳监测单个活囊泡连续释放

Carbon fiber nanoelectrode(tip diameter ca. 100nm)-patch clamp was firstly applied to realtime monitoring dopamine release from single living vesicles of single Rat pheochromocytoma (PC12) cells with highly temporal and spatial resolution. It is first demonstrated that there are continual vesicle releases of dopamine at the same site in the active release zone, which play a main role in the exocytosis.