Nakahara Hiromichi, Nakamura Shohei, Kawasaki Hideya, Shibata Osamu
Division of Biointerfacial Science, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Fukuoka 812-8582, Japan.
Colloids Surf B Biointerfaces. 2005 Apr 10;41(4):285-98. doi: 10.1016/j.colsurfb.2004.06.013.
The surface pressure (pi)- and the surface potential (DeltaV)-area (A) isotherms were obtained for two-component monolayers of four different perfluorocarboxylic acids (FCns; perfluorododecanoic acid: FC12, perfluorotetradecanoic acid: FC14, perfluorohexadecanoic acid: FC16, perfluorooctadecanoic acid: FC18) with dipalmitoylphosphatidylcholine (DPPC) on substrate solution of 0.15 M NaCl (pH 2.0) at 298.2 K as a function of compositions in the mixtures by employing the Wilhelmy method, the ionizing electrode method, the fluorescence microscopy, and the atomic force microscopy. The data for the two-component monolayers on these systems were analyzed in terms of the additivity rule. Assuming a regular surface mixture, the Joos equation which allows one to describe the collapse pressure of a two-component monolayer with miscible components was used to declare the miscibility of the monolayer state, and an interaction parameter and an interaction energy were calculated. The new finding was that FCns and DPPC are miscible or immiscible depending on chain length increment of fluorocarbon part. That is, FC12/DPPC monolayer was perfectly miscible, and FC14/DPPC, and FC16/DPPC (0 < or = X(FC16) < or = 0.3) monolayers were partially miscible. While FC16/DPPC (0.3 < X(FC16) < 1) and FC18/DPPC systems are immiscible in the monolayer state. Furthermore, the mean molecular area, the surface dipole moment, and the phase diagrams enabled us to estimate the molecular orientation of four different perfluorocarboxylic acids/DPPC in the two-component monolayer state. One type of phase diagrams was obtained and classified into the positive azeotropic type. The miscibility of FCns and DPPC in the monolayer was also supported by fluorescence microscopy and atomic force microscopy. FC12/DPPC, FC14/DPPC and FC16/DPPC (0 < or = X(FC16) < or = 0.3) two-component monolayers on 0.15 M NaCl (pH 2) showed that FC12, FC14 and FC16 (0 < or = X(FC16) < or = 0.3) can dissolve or partially dissolve the ordered solid DPPC domains formed upon compression. This indicates that these fluorinated amphiphiles soften or harden the lipid depending on their chain length.
采用威尔海姆法、电离电极法、荧光显微镜法和原子力显微镜法，在298.2K温度下，于0.15M NaCl（pH 2.0）的底物溶液中，研究了四种不同的全氟羧酸（FCns；全氟十二烷酸：FC12、全氟十四烷酸：FC14、全氟十六烷酸：FC16、全氟十八烷酸：FC18）与二棕榈酰磷脂酰胆碱（DPPC）二元单层膜的表面压力（π）-面积（A）等温线以及表面电位（ΔV）-面积（A）等温线，这些等温线是混合物组成的函数。根据加和规则分析了这些体系中二元单层膜的数据。假设为规则表面混合物，使用允许描述具有可混溶组分的二元单层膜崩塌压力的约斯方程来表明单层状态的混溶性，并计算了相互作用参数和相互作用能。新的发现是，FCns和DPPC是混溶还是不混溶取决于碳氟链部分的链长增量。也就是说，FC12/DPPC单层膜完全混溶，FC14/DPPC和FC16/DPPC（0≤X(FC16)≤0.3）单层膜部分混溶。而FC16/DPPC（0.3＜X(FC16)＜1）和FC18/DPPC体系在单层状态下不混溶。此外，平均分子面积、表面偶极矩和相图使我们能够估计二元单层状态下四种不同全氟羧酸/DPPC的分子取向。获得了一种相图并将其归类为正共沸型。荧光显微镜法和原子力显微镜法也支持了FCns和DPPC在单层中的混溶性。在0.15M NaCl（pH 2）上的FC12/DPPC、FC14/DPPC和FC16/DPPC（0≤X(FC16)≤0.3）二元单层膜表明，FC12、FC14和FC16（0≤X(FC16)≤0.3）可以溶解或部分溶解压缩时形成的有序固体DPPC区域。这表明这些氟化两亲物根据其链长使脂质软化或硬化。
