Hydrostatic pressure effects on the lamellar to gyroid cubic phase transition of monolinolein at limited hydration.
Hydrostatic pressure effects on the lamellar to gyroid cubic phase transition of monolinolein at limited hydration.
复制标题
DOI：
10.1021/la3025843
复制
发表时间：
2012-08
期刊：
影响因子：
--
通讯作者：
T. Tang;N. Brooks;C. Jeworrek;O. Ces;N. Terrill;R. Winter;R. Templer;J. Seddon
中科院分区：
文献类型：
--
作者：
T. Tang;N. Brooks;C. Jeworrek;O. Ces;N. Terrill;R. Winter;R. Templer;J. Seddon
单酰基甘油为基础的脂质是非常重要的模型膜成分和有吸引力的候选药物包封和作为递送剂。然而，优化这些脂质的应用需要详细了解控制它们形成的自组装结构的热力学因素。在这里，我们报道了静水压力、温度和水组成对单油酸（一种碳位9和12具有顺式双键的不饱和单酰基甘油）在有限水化条件下所采用的反溶变液晶相的结构行为和稳定性的影响。在10-40°C和1-3000 bar范围内，使用小角x射线衍射确定了6个压力-温度相图，水含量在15 wt %和27 wt %之间。在低压和高温条件下形成了双连续立方(Q（II)(G)）相，在高压和低温条件下通过Q(II)(G)/L（α）共存区转变为流体片层（L(α)）相。压力稳定了Q(II)(G)相的片层相；在固定压力下，增加水的含量使共存区向较低的温度移动。这些趋势在研究的水合作用范围内是一致的。此外，在一定温度下，增加水的组成增加了发生Q(II)(G)向L（α）转变的压力。我们讨论了压力、温度和含水量对Q(II)(G)相稳定性的定性影响。
Monoacylglycerol based lipids are highly important model membrane components and attractive candidates for drug encapsulation and as delivery agents. However, optimizing the properties of these lipids for applications requires a detailed understanding of the thermodynamic factors governing the self-assembled structures that they form. Here, we report on the effects of hydrostatic pressure, temperature, and water composition on the structural behavior and stability of inverse lyotropic liquid crystalline phases adopted by monolinolein (an unsaturated monoacylglycerol having cis-double bonds at carbon positions 9 and 12) under limited hydration conditions. Six pressure-temperature phase diagrams have been determined using small-angle X-ray diffraction at water contents between 15 wt % and 27 wt % water, in the range 10-40 °C and 1-3000 bar. The gyroid bicontinuous cubic (Q(II)(G)) phase is formed at low pressure and high temperatures, transforming to a fluid lamellar (L(α)) phase at high pressures and low temperature via a region of Q(II)(G)/L(α) coexistence. Pressure stabilizes the lamellar phase over the Q(II)(G) phase; at fixed pressure, increasing the water content causes the coexistence region to move to lower temperature. These trends are consistent throughout the hydration range studied. Moreover, at fixed temperature, increasing the water composition increases the pressure at which the Q(II)(G) to L(α) transition takes place. We discuss the qualitative effect of pressure, temperature, and water content on the stability of the Q(II)(G) phase.