Dynamic Behaviors and Morphology Change of Anionic Phospholipid DPPG Monolayer Caused by Bovine Serum Albumin at Air-Water Interface  

在气/液界面牛血清蛋白对阴离子磷脂DPPG脂单层膜的动态行为和形貌变化的影响

作　　者：徐国庆[1] 郝长春[1] 张蕾[1] 陈时[1] 孙润广[1] 

机构地区：[1]陕西师范大学物理学与信息技术学院,西安710062

出　　处：《Chinese Journal of Chemical Physics》2017年第5期595-602,I0002,共9页化学物理学报（英文）

基　　金：This work was supported by the National Natural Science Foundation of China （No.21402114）, the Natural Science Basic Research Plan in Shaanxi Province of China （2016JM2010 and 2014JM1013）, the Fundamental Research Funds for the Central Universities （2017CSY004, GK201603026）.

摘　　要：The interaction between bovine serum albumin （BSA） and the anionic 1.2-dipalmitoyl-snglycero- 3-（phospho-rac-（1-glycerol）） （sodium salt） （DPPG） phospholipid at different subphase pH values was investigated at air-water interface through surface pressure measurements and atomic force microscopy （AFM） observation. By analyzing surface pressure-mean molecular area （π-A） isotherms, the limiting molecular area in the closed packing state-the concentration of BSA （Alim-[BSA]） curves, the compressibility coefficient-surface pressure （CS-1-π） curves and the difference value of mean molecular area-the concentration of BSA （ΔA-[BSA]） curves, we obtained that the mean molecular area of DPPG monolayer became much larger when the concentration of BSA in the subphase increased at pH=3 and 5. But the isotherms had no significant change at different amount of BSA at pH=10. In addition, the amount of BSA molecules adsorbed onto the lipid monolayer reached a threshold value when [BSA]〉5×10-8 mol/L for all pHs. From the surface pressure-time （π-t） data, we obtained that desorption and adsorption processes occurred at pH=3, however, there was only desorption process occurring at pH=5 and 10. These results showed that the interaction mechanism between DPPG and BSA molecules was affected by the pH of subphase. BSA molecules were adsorbed onto the DPPG monolayers mainly through the hydrophobic interaction at pH=3 and 5, and the strength of hydrophobic interaction at pH=3 was stronger than the case of pH=5. At pH=10, a weaker hydrophobic interaction and a stronger electrostatic repulsion existed between DPPG and BSA molecules. AFM images revealed that the pH of subphase and [BSA] could affect the morphology features of the monolayers, which was consistent with these curves. The study provides an important experimental basis and theoretical support to understand the interaction between lipid and BSA at the air-water interface.

关 键 词：Bovine serum albumin  DPPG  Isotherm  Interaction 

分 类 号：O[理学]