Unidad de Biofísica (CSIC-UPV/EHU), and Departamento de Bioquímica, Universidad del País Vasco, Bilbao, Spain.
Biophys J. 2012 Jan 18;102(2):278-86. doi: 10.1016/j.bpj.2011.12.026.
Oleic acid vesicles have been used as model systems to study the properties of membranes that could be the evolutionary precursors of more complex, stable, and impermeable phospholipid biomembranes. Pure fatty acid vesicles in general show high sensitivity to ionic strength and pH variation, but there is growing evidence that this lack of stability can be counterbalanced through mixtures with other amphiphilic or surfactant compounds. Here, we present a systematic experimental analysis of the oleic acid system and explore the spontaneous formation of vesicles under different conditions, as well as the effects that alcohols and alkanes may have in the process. Our results support the hypothesis that alcohols (in particular 10- to 14-C-atom alcohols) contribute to the stability of oleic acid vesicles under a wider range of experimental conditions. Moreover, studies of mixed oleic-acid-alkane and oleic-acid-alcohol systems using infrared spectroscopy and Langmuir trough measurements indicate that precisely those alcohols that increased vesicle stability also decreased the mobility of oleic acid polar headgroups, as well as the area/molecule of lipid.
油酸囊泡已被用作模型系统来研究可能是更复杂、稳定和不可渗透的磷脂生物膜的进化前体的膜的性质。一般来说，纯脂肪酸囊泡对离子强度和 pH 值变化非常敏感，但越来越多的证据表明，这种不稳定性可以通过与其他两亲或表面活性剂化合物的混合物来平衡。在这里，我们对油酸体系进行了系统的实验分析，并探索了在不同条件下囊泡的自发形成，以及醇和烷烃在该过程中可能产生的影响。我们的结果支持了这样一种假设，即醇（特别是 10 到 14 个碳原子的醇）有助于油酸囊泡在更广泛的实验条件下稳定。此外，使用红外光谱和 Langmuir 槽测量对油酸-烷烃和油酸-醇混合体系的研究表明，正是那些增加囊泡稳定性的醇也降低了油酸极性头部基团的流动性，以及脂质的面积/分子。
