油酸囊泡尺度多分散性及二元醇对其pH窗口的影响

Size Polydispersity of Oleic Acid Vesicles and Effects of Diols on the pH Window of the Vesicles

以油酸(OA)为模型脂肪酸,依据目测激光丁达尔现象在pH滴定曲线上划分相区,确定OA囊泡化pH窗口为8.2~10.1.利用光学显微镜、激光共聚焦显微镜和冷冻刻蚀-透射电子显微镜共同表征了OA囊泡的形貌及粒径,发现体系中微米和亚微米级的多层囊泡以及纳米级的单层囊泡共存,呈现尺度多分散性.用不同链长的短链二元醇辅助OA形成囊泡,结果表明,短链二元醇有助于脂肪酸囊泡(FAV)的pH窗口拓宽,拓宽的方向取决于表面氢键作用方式或疏水插入方式.在酸性条件下二元醇与FAV相互作用后,在囊泡表面残留的自由羟基越多,越有助于拓宽其酸性pH窗口.

Oleic acid(OA)was selected as a model fatty acid,and the pH window of OA vesicles was 8.2—10.1 confirmed by phase division in the pH titration curve depending on the observation of laser Tyndall effects.Particle sizes and morphology of the OA vesicles were characterized by optical microscopy,confocal laser microscopy and freeze-fracture transmission electron microscopy.It is found that the micro-and sub-micro-sized fatty acid vesicle(FAV)are multilamellar vesicles while nano-sized FAV are unilamellar vesicles,which coexist in the aqueous solution,indicating the size polydispersity of OA vesicles.A series of short-chain diols are used to assist the formation of OA vesicles,which showed that the short-chain diols are favorable for the pH window extension of FAV.The extension direction may depend on the modes of either surface hydrogen bonding or hydrophobic insertion.It is suggested that if more hydroxyl groups of the used diol remained on the FAV surface after interaction,the acidic pH window would extend.