Nonequilibrium behavior in supported lipid membranes containing cholesterol.
Nonequilibrium behavior in supported lipid membranes containing cholesterol.
复制标题
含有胆固醇的支持脂质膜的非平衡行为。
DOI：
10.1016/s0006-3495(04)74345-3
复制
发表时间：
2004
影响因子：
3.4
通讯作者：
Keller,SarahL
中科院分区：
文献类型：
--
作者：
Stottrup,BenjaminL;Veatch,SarahL;Keller,SarahL
我们研究了囊泡中脂域的侧向组织与支持的膜和单层。所使用的脂类混合物主要是DOPC/DPPC/Chol和DOPC/BSM/Chol，先前已证明它们会在囊泡和单层中产生共存的液体相。在空气-水界面的单分子膜中，这些脂类具有12-15mN/m的混溶转变压力，如果单分子膜暴露在空气中，则可以上升到32mN/m。通过Langmuir-Schäfer沉积可以将脂单分子层转移到硅烷化玻璃或现有的Langmuir-Blodgett支撑单分子膜上。微米级的结构域只有在沉积前存在于原始单层中的情况下才存在于转移的脂类中。这一结果适用于32mN/m和较低压力下的转移。转移到玻璃载体上的结构域不同于囊泡中的液体结构域，因为它们是静态的，不会在小叶上对齐，并且在温度循环后不会再次出现。对于破裂在玻璃表面上的小泡，也发现了类似的静态区域。尽管玻璃上的支撑膜捕获了平衡状态下的囊泡的某些方面(例如，凝胶-液体转变温度和单个脂类的扩散速率)，但脂类在大液区的集体行为很难再现。
We investigate lateral organization of lipid domains in vesicles versus supported membranes and monolayers. The lipid mixtures used are predominantly DOPC/DPPC/Chol and DOPC/BSM/Chol, which have been previously shown to produce coexisting liquid phases in vesicles and monolayers. In a monolayer at an air-water interface, these lipids have miscibility transition pressures of ∼12–15mN/m, which can rise to 32mN/m if the monolayer is exposed to air. Lipid monolayers can be transferred by Langmuir-Schäfer deposition onto either silanized glass or existing Langmuir-Blodgett supported monolayers. Micron-scale domains are present in the transferred lipids only if they were present in the original monolayer before deposition. This result is valid for transfers at 32mN/m and also at lower pressures. Domains transferred to glass supports differ from liquid domains in vesicles because they are static, do not align in registration across leaflets, and do not reappear after temperature is cycled. Similar static domains are found for vesicles ruptured onto glass surfaces. Although supported membranes on glass capture some aspects of vesicles in equilibrium (e.g., gel-liquid transition temperatures and diffusion rates of individual lipids), the collective behavior of lipids in large liquid domains is poorly reproduced.