FLinT (Center for Fundamental Living Technology), Institute of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
Langmuir. 2011 Dec 6;27(23):14078-90. doi: 10.1021/la203057b. Epub 2011 Oct 28.
The self-assembly of cationic and anionic amphiphile mixtures into vesicles in aqueous media was studied using two different systems: (i) decanoic acid and trimethyldecylammonium bromide and (ii) hexadecanedioic acid (a simple bola-amphiphile) and trimethyldecylammonium bromide. The resulting vesicles with varying amphiphile ratios were characterized using parameters such as the critical vesicle concentration, pH sensitivity, and encapsulation efficiency. We also produced and observed giant vesicles from these mixtures using the electroformation method and confocal microscopy. The mixed catanionic vesicles were shown to be more stable than those formed by pure fatty acids. Those containing bola-amphiphile even showed the encapsulation of a small hydrophilic solute (8-hydroxypyrene-1,3,6-trisulfonic-acid), suggesting a denser packing of the amphiphiles. Compression and kinetics analysis of monolayers composed of these amphiphiles mixtures at the air/water interface suggests that the stabilization of the structures can be attributed to two main interactions between headgroups, predominantly the formation of hydrogen bonds between protonated and deprotonated acids and the additional electrostatic interactions between ammonium and acid headgroups.
在水介质中，通过两种不同的体系（i）癸酸和三甲基十二烷基溴化铵，以及（ii）十六烷二酸（一种简单的双偶极型两亲分子）和三甲基十二烷基溴化铵，研究了阳离子和阴离子两亲混合物自组装为囊泡的情况。使用临界囊泡浓度、pH 敏感性和包封效率等参数对具有不同两亲物比例的所得囊泡进行了表征。我们还使用电形成法和共聚焦显微镜从这些混合物中产生和观察了巨大囊泡。混合的反离子囊泡比由纯脂肪酸形成的囊泡更稳定。那些含有双偶极两亲分子的囊泡甚至显示出对小亲水性溶质（8-羟基芘-1,3,6-三磺酸）的包封，表明两亲分子的密度更高。在空气/水界面上由这些两亲混合物组成的单层的压缩和动力学分析表明，结构的稳定可以归因于头基之间的两种主要相互作用，主要是质子化和去质子化酸之间氢键的形成以及铵和酸头基之间额外的静电相互作用。
