化学学报 ›› 2012, Vol. 0 ›› Issue (05): 599-605 .DOI: 10.6023/A1012284 上一篇    下一篇

研究论文

胆固醇与磷脂酰乙醇胺/磷脂酰胆碱混合膜的热力学特性及其单层膜形态的AFM 观察

王娟, 常怡光, 孙润广   

  1. 陕西师范大学物理学与信息技术学院 生物物理与生物医学工程实验室 西安 710062
  • 投稿日期:2010-12-28 修回日期:2011-10-10 发布日期:2012-03-17
  • 通讯作者: 孙润广 E-mail:sunrunguang@snnu.edu.cn
  • 基金资助:

    国家自然科学基金项目(No. 20772077)和教育部高等学校博士学科点专项科研基金(No. 200807180001)资助项目.

Thermodynamic Study on the Monolayer Mixed with Different Chol-content and PE/PC and the Morphology Observation of the Bilayers

Wang Juan, Chang Yiguang, Sun Runguang   

  1. Laboratory of Biophysics and Biomedicine, College of Physics and Information Technology, Shaanxi Normal University, Xi'an, 710062
  • Received:2010-12-28 Revised:2011-10-10 Published:2012-03-17
  • Supported by:

    Project supported by the National Natural Science Foundation of China (No. 20772077), and Research Fund for the Doctoral Program of Higher Education of China (No. 200807180001).

研究了不同比例下胆固醇(Chol)对磷脂酰乙醇胺/磷脂酰胆碱(PE/PC, 1∶1 物质的量比)混合膜的影响, 并在表面压力-平均分子面积(π-A 曲线)等温线基础上, 通过对过量平均分子面积(ΔAex)和过量吉布斯自由能(ΔGex)的计算分析,研究了不同比例Chol 与PE/PC (1∶1 物质的量比)三元混合膜的热力学特性. 实验结果表明: Chol 在一定程度上加速了混合膜的相变, 增强了膜的凝聚性; 当XChol=0.2, 0.6, 0.8 时, 过量平均分子面积和过量吉布斯自由能在所研究的表面压力下都为负值, 分子之间相互作用力表现为引力, 促使混合膜的凝聚, 而在XChol=0.4 时, 过量平均分子面积和过量吉布斯自由能在15, 20, 25, 30 mN/m 下为正值, 分子之间相互作用力表现为斥力, 促使熵的增加, 并且在20 mN/m 压力下出现极值. 实验中利用LB 膜技术制备了不同比例Chol 与PE/PC (1∶1 物质的量比)混合膜, 并在原子力显微镜下对其结构形态进行了观测.

关键词: 生物膜, LB 膜技术, 过量吉布斯自由能, 等温线, 原子力显微镜

The effect of different cholesterol (Chol)-content on the mixed monolayer of the phosphatidylethanolamine (PE)/phosphatidylcholine (PC) (1∶1 molar ratio) has been investigated by analyzing the surface pressure-area isotherms. And the thermodynamic behavior of mixed monolayer of Chol and PE/PC (1∶1 molar ratio) has been investigated by calculating and analyzing the excess molecular area and excess Gibbs energy (ΔAex and ΔGex). The results show that Chol accelerated the phase transition and promoted the aggregation of monolayer. When XChol=0.2, 0.6, 0.8, ΔAex and ΔGex displayed negative values, suggesting attractive interaction between molecules. While XChol=0.4, ΔAex and ΔGex displayed positive values at the surface pressure of 15, 20, 25, 30 mN/m, indicating repelling interaction between molecules, promoting the increasing of the entropy. In addition, the deposited Langmuir-Blodgett (LB) monolayers of different ratios were investigated with atomic force microscopy (AFM).

Key words: biomembrane, the LB film technique, excess Gibbs energy, isotherm, atomic force microscopy