Investigation of temperature-induced phase transitions in DOPC and DPPC phospholipid bilayers using temperature-controlled scanning force microscopy
Investigation of temperature-induced phase transitions in DOPC and DPPC phospholipid bilayers using temperature-controlled scanning force microscopy
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DOI：
10.1529/biophysj.103.036681
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发表时间：
2004-06-01
影响因子：
3.4
通讯作者：
Cramb, DT
中科院分区：
文献类型：
--
作者：
Leonenko, ZV;Finot, E;Cramb, DT
在生理条件下，多组分生物膜会发生结构变化，这有助于确定膜的功能。对生物膜结构-功能关系的理解可以基于对纯磷脂双层的物理和化学性质的了解。在这里，我们研究了二棕榈酰磷脂酰胆碱（DPPC）和二油酰磷脂酰胆碱（DOPC）双层的相变。我们通过原子力显微镜成像和力测量证明了 DPPC 和 DOPC 云母支撑的双层中存在几种相变。支持的 DPPC 双层显示出广泛的 L-β-L-α 转变。除了主转变之外，我们还观察到主转变温度之上和之下的结构变化，其中包括双层覆盖度的增加和双层高度的变化。力测量提供了有关双层厚度和相变的宝贵信息，并且与原子力显微镜成像数据非常一致。 De Gennes 模型用于表征排斥位阻力，作为支撑双层弹性特性的起源。静电力和空间力都对力图的排斥部分有贡献。
Under physiological conditions, multicomponent biological membranes undergo structural changes which help define how the membrane functions. An understanding of biomembrane structure-function relations can be based on knowledge of the physical and chemical properties of pure phospholipid bilayers. Here, we have investigated phase transitions in dipalmitoylphosphatidylcholine (DPPC) and dioleoylphosphatidylcholine (DOPC) bilayers. We demonstrated the existence of several phase transitions in DPPC and DOPC mica-supported bilayers by both atomic force microscopy imaging and force measurements. Supported DPPC bilayers show a broad L-beta-L-alpha transition. In addition to the main transition we observed structural changes both above and below main transition temperature, which include increase in bilayer coverage and changes in bilayer height. Force measurements provide valuable information on bilayer thickness and phase transitions and are in good agreement with atomic force microscopy imaging data. A De Gennes model was used to characterize the repulsive steric forces as the origin of supported bilayer elastic properties. Both electrostatic and steric forces contribute to the repulsive part of the force plot.