Two-component Langmuir monolayers of single-chain partially fluorinated amphiphiles with dipalmitoylphosphatidylcholine (DPPC).
Two-component Langmuir monolayers of single-chain partially fluorinated amphiphiles with dipalmitoylphosphatidylcholine (DPPC).
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DOI：
10.1021/la702420v
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发表时间：
2007-11
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影响因子：
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通讯作者：
Shohei Nakamura;H. Nakahara;M. Krafft;O. Shibata
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文献类型：
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作者：
Shohei Nakamura;H. Nakahara;M. Krafft;O. Shibata
测定了双棕榈酰磷脂酰胆碱(DPPC)/单链(全氟辛基)戊醇(F8C5OH)和双棕榈酰磷脂酰胆碱(F8C5PC)/单链(全氟辛基)磷酸胆碱(F8C5PC)组成的双组分单分子膜在293.2 K下的表面压力(Pi)-面积(A)和表面电位(DeltaV-A)等温线随两组分组成的变化关系。采用朗缪尔法和离子电极法。使用可加性规则对这些系统的数据进行分析。假设有规则的表面混合物，Joos方程可以描述由两个可混溶的组分组成的单层的崩塌压力，用来建立单层内的混相性。计算了相互作用参数和相互作用能。双组分DPPC/F8C5OH和DPPC/F8C5PC单分子膜是相容的。此外，平均分子面积、表面电势和相图使我们能够确定DPPC/F8C5OH和DPPC/F8C5PC在单分子膜中的分子取向。得到了两种类型的相图，并将其分为正共沸型和负共沸型。DPPC/F8C5OH和DPPC/F8C5PC体系的荧光显微镜(FM)和布鲁斯特角显微镜(BAM)表明，这两个体系都能溶解微米级的有序固体DPPC结构域。然而，原子力显微镜(AFM)的形态分析表明，DPPC和部分含氟化合物在纳米尺度上是部分混溶或相分离的。特别是，F8C5OH的三kelion结构域被证明。这些结果表明，这里研究的部分氟化两亲分子在横向压缩时使DPPC单层流态化，这些化学物质可能有助于开发它们在生物医学领域的创新应用。
The surface pressure (pi)-area (A) and surface potential (DeltaV)-A isotherms were measured for two-component monolayers made of dipalmitoylphosphatidylcholine (DPPC)/single-chain (perfluorooctyl)pentanol (F8C5OH) and DPPC/single-chain (perfluorooctyl)pentylphosphocholine (F8C5PC) on a substrate solution of 0.15 M NaCl at 293.2 K as a function of the composition of the two components. The Langmuir method and the ionizing electrode method were used. The data for these systems were analyzed using an additivity rule. Assuming a regular surface mixture, the Joos equation, which allows description of the collapse pressure of a monolayer made of two miscible components, was used to establish the miscibility within the monolayer. An interaction parameter and an interaction energy were calculated. The two-component DPPC/F8C5OH and DPPC/F8C5PC monolayers were miscible. Furthermore, the mean molecular area, surface potential, and phase diagrams enabled us to determine the molecular orientation of DPPC/F8C5OH and DPPC/F8C5PC in the monolayer. Two types of phase diagrams were obtained and classified into the positive azeotropic and negative azeotropic types. Fluorescence microscopy (FM) and Brewster angle microscopy (BAM) for the DPPC/F8C5OH and DPPC/F8C5PC systems show that both systems can dissolve the ordered micrometer-size solid DPPC domains. However, morphological analyses using atomic force microscopy (AFM) suggest partial miscibility or phase separation for DPPC and the partially fluorinated compounds on the nanometer scale. In particular, triskelion-shaped domains were evidenced for F8C5OH. These results indicate that the partially fluorinated amphiphiles investigated here fluidize the DPPC monolayer upon lateral compression and that these chemicals may be useful to develop their innovative applications in the biomedical field.