Study on Higher Order Phase Transition of Phospholipid Bilayrs and Stability of Emulsion Formed with These Disperisons

磷脂双层的高阶相变及其分散体乳液的稳定性研究

基本信息

批准号：
06453059
负责人：
TAJIMA Kazuo
金额：
$ 4.74万
依托单位：
Kanagawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06453059/
关键词：
ESR spectra for phospholipid bilayr Thermal properties of DMPC Thermal properties of DMPG Higher order phase transition in bilayr Emulsifier of phospholipid Stability of emulsion Coalescene kinetics Preparation of emulsion with phospholipids

项目摘要

This work was carried out to make clear the thermal properties of lamellar liquid crystals of dimyristoylphosphatidylcholine (DMPC) and dimyristoryphosphatidylglycerol (DMPG) dispersed in water, and emulsions of hexadecane formed with these lipids. Main measurements for the lipid dispersions were made on the temperature dependence of heat capacity at constant pressure, equilibrium apread pressure on water, X-ray diffraction analysis, ESR spectra, DSC,and zeta-Potential.As a result, it was confirmed from these experiments that in the lamellar liquid crystals of the (L_<alpha>+H_2O) phase a higher order phase transition of bilayr occurred at the temperatures several degrees higher than their gel-liquid crystral transition temperatures (Tm ; 23.5ﾟC for DMPC and 23.7ﾟC for DMPG). The higher order phase transition for these lipids were observed at 29.0ﾟC for DMPC dispersion and at 31.7ﾟC for DMPG dispersion. The physical and surface-chemical properties of these phospholipids were found to d … More iffer incredibly below and above T^<**>.Subsequently, the emulsification of hexadecane with DMPC dispersion was investigated below and above T^<**> temperature. It was found that the particle size, zeta-potential, and thermal stability of emulsion were changed in paralell with the variation of the thermal properties of DMPC dispersion at T^<**>. Especially, a new finding was that when hexadecane wa emulsified with DMPC at a temperature between Tm and T^<**>, the emulsion surface was covered and stabilized with the triple layrs of DMPC,but above T^<**> the surface of emulsion was composed of a monolayr of DMPC as a usual surfactant. This observation was supported by the precise study on the coalescence kinetics for the DMPC stabilized hexadecane emulsion. The conclusion was that the activation energy for coalescence of the emulsion taking place below T^<**> was twice lager than that for coalescence above T^<**>. This may explain why the emulsion formed with DMPC above T^<**> became less stable. Less

这项工作的目的是弄清楚分散在水中的二肉豆蔻酰磷脂酰胆碱（DMPC）和二肉豆蔻酰磷脂酰甘油（DMPG）的层状液晶以及由这些脂质形成的十六烷乳液的热性质。对脂质分散体的主要测量是根据温度依赖性进行的。恒压热容、水平衡压力、X 射线衍射分析、ESR结果表明，(L_α+H_2O)相层状液晶在温度升高几度时会发生双层高阶相变。比它们的凝胶-液晶转变温度（Tm；DMPC 为 23.5°C，DMPG 为 23.7°C）。在 29.0°C 的 DMPC 分散体和 31.7°C 的 DMPG 分散体中观察到脂质的物理和表面化学性质在 T^<**> 之下和之上存在令人难以置信的差异。在低于和高于T^**温度的情况下研究了十六烷与DMPC分散体的乳化，发现颗粒尺寸、特别是，当十六烷与DMPC在Tm和Tm之间乳化时，乳液的zeta电位和热稳定性随着DMPC分散体在T^<**>的热性能的变化而变化。 T^<**>，乳液表面被三层 DMPC 覆盖并稳定，但高于 T^<**>，乳液表面由单层 DMPC 组成DMPC 作为常用的表面活性剂，得到了对 DMPC 稳定的十六烷乳液的聚结动力学的精确研究的支持，结论是，低于 T^<**> 时乳液聚结的活化能比 T^<**> 大两倍。对于高于 T^<**> 的聚结，这可以解释为什么使用高于 T^<**> 的 DMPC 形成的乳液变得不太稳定。