Mechano-chemistry of closed, vesicular membrane systems
Mechano-chemistry of closed, vesicular membrane systems
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封闭囊泡膜系统的机械化学
DOI：
10.1016/0021-9797(77)90288-0
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发表时间：
1977
影响因子：
9.9
通讯作者：
R. Waugh
中科院分区：
文献类型：
--
作者：
E. Evans;R. Waugh
大囊泡或生物细胞的封装膜表面中的表面压力的定义不能以与不溶性单层相同的方式来表述，也不能像在单层系统中那样直接测量表面压力。我们的方法是确定大囊泡和生物细胞的封闭膜系统中表面压力的合适定义；该表面压力将代表膜的内部状态方程，可以与观察到的单层表面压力与面积行为进行比较。使用机械实验产生各向同性膜张力和面积膨胀，可以将表面压力的变化确定为面积变化的函数。各向同性张力与表面积之间的关系称为“力化学”状态方程。我们直接将内部状态方程（表面压力与面积）与机械化学状态方程（各向同性张力与面积）联系起来。利用这种关系，通过各向同性膨胀或表面积减少在封闭的囊泡（或细胞）膜中产生的热力学变化可以通过实验确定的变量进行研究和描述。这些变量包括等温压缩模量 K T、恒定或零各向同性张力下的热面积膨胀率 (∂ α∂ T) T-0、面积压缩模量的温度梯度 (dK T dT) 以及恒定或零各向同性张力下的比热 C T。结合已知的状态方程，热弹性变化可直接评估疏水相互作用的界面自由能密度的温度依赖性。在没有外力的情况下，表面压力由疏水相互作用的界面自由能密度决定。
The definition of a surface pressure in the encapsulating membrane surface of a large vesicle or biological cell cannot be stated in the same manner as for an insoluble monolayer, nor can a surface pressure be measured directly, as in a monolayer system. Our approach is to determine a suitable definition for surface pressure in closed membrane systems of large vesicles and biological cells; this surface pressure will represent an internal equation of state for the membrane that can be compared with the observed monolayer surface pressure versus area behavior. Using mechanical experiments to produce isotropic membrane tension and area expansion, changes in surface pressure can be determined as a function of area change. The relationship between isotropic tension and surface area is called the “mechano-chemical” equation of state. We directly relate the internal equation of state, surface pressure versus area, to the mechano-chemical equation of state, isotropic tension versus area. Using this relationship, the thermodynamic changes produced in a closed, vesicular (or cellular) membrane by isotropic dilation or reduction in surface area are investigated and described in terms of experimentally determinable variables. These variables include the isothermal compressibility modulus, K T, the thermal area expansivity at constant or zero isotropic tension,(∂ α∂ T) T-0, the temperature gradient in the area compressibility modulus,(dK T dT), and the specific heat at constant or zero isotropic tension, C T. In conjunction with known equations of state, the thermoelastic change provides direct assessment of the temperature dependence of the interfacial free-energy density of hydrophobic interaction. In the absence of external forces, the surface pressure is determined by the interfacial free-energy density of hydrophobic interaction.