Department of Physics, University of Calabria, 87036 Rende, CS, Italy.
Department of Chemistry and Chemical Technologies, University of Calabria, 87036 Rende, CS, Italy.
Biochim Biophys Acta Biomembr. 2018 Jun;1860(6):1253-1258. doi: 10.1016/j.bbamem.2018.02.021. Epub 2018 Feb 27.
Many cell membranes of living organisms can be represented as phospholipid bilayers immersed into a water environment. The physical-chemical interactions at the membranes/water interface are responsible for the stabilization of the membranes. In addition, the drug efficiency, the pharmaceutical mechanism and the improvement of the drug design can be addressed to the interactions between the membranes-water interface with the drug and to the membrane-drug interface. In this framework, it is important to find membranes models able to simulate and simultaneously simplify the biological systems to better understand both physical and chemical interactions at the interface level. Dimyristoylphosphatidylcholine (DMPC) is a synthetic phospholipid used in order to make Multilamellar Vesicle (MLV), Large Unilamellar Vesicle (LUV) and Giant Unilamellar Vesicle (GUV). In order to understand the mechanisms of vesicle formation, we have analyzed mixtures of DMPC and water by micro-Raman spectroscopy at different temperatures in the range between 10 and 35 °C. Particularly, we analyzed the temperature dependence of the CN vibrational frequency, which appears well correlated to the order degree of the various phases. These investigations, beyond the determination of phospholipid hydrocarbon chains order, provide information about the conformation of the lipid membranes. We have identified the mixture of DMPC/water that is best suited for Raman studies and can be used as an in-vitro model for biological systems. A peculiar frequency shift across the transition gel-ripple-liquid crystalline phases has been proposed as a useful diagnostic marker to detect the "order degree" and subsequently the phases of biomimetic membranes made by DMPC.
许多生物的细胞膜可以表示为沉浸在水环境中的磷脂双层。细胞膜/水界面的物理化学相互作用负责稳定细胞膜。此外，药物效率、药物机制和药物设计的改进都可以通过药物与膜-水界面以及膜-药物界面之间的相互作用来解决。在这种框架下，找到能够模拟和简化生物系统的膜模型以更好地理解界面水平的物理和化学相互作用非常重要。二肉豆蔻酰磷脂酰胆碱 (DMPC) 是一种用于制备多层囊泡 (MLV)、大单室囊泡 (LUV) 和大单层囊泡 (GUV) 的合成磷脂。为了了解囊泡形成的机制，我们在 10 至 35°C 的范围内通过微拉曼光谱分析了不同温度下 DMPC 和水的混合物。特别是，我们分析了 CN 振动频率随温度的依赖性，该依赖性与各个相的有序度很好地相关。这些研究除了确定磷脂烃链的有序度外，还提供了关于脂质膜构象的信息。我们已经确定了最适合拉曼研究的 DMPC/水混合物，并可以用作生物系统的体外模型。在凝胶-波纹-液晶各相之间已经提出了一种特殊的频率偏移作为有用的诊断标记，以检测“有序度”，随后检测由 DMPC 制成的仿生膜的相。
