Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan, Canada S7N 5C9.
Langmuir. 2012 Oct 30;28(43):15150-9. doi: 10.1021/la3026655. Epub 2012 Oct 17.
Monolayer surfactant films composed of a mixture of phospholipids and perfluorinated (or partially fluorinated) surfactants are of potential utility for applications in pulmonary lung surfactant-based therapies. As a simple, minimal model of such a lung surfactant system, binary mixed monolayer films composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and perfluorooctadecanoic acid (C18F) prepared on a simplified lung fluid mimic subphase (pH 7.4, 150 mM NaCl) have been characterized in terms of mixing thermodynamics and compressibility (measured through π–A compression isotherms), film morphology (via atomic force, fluorescence, and Brewster angle microscopy), as well as spreading rate and hysteresis response to repeated expansion–contraction cycles for a variety of compositions of mixed films. Under all mixing conditions, films and their components were found to be completely immiscible and phase-separated, though there were significant changes in the aforementioned film properties as a function of composition. Of particular note was the existence of a maximum in the extent of immiscibility (characterized by ΔG(ex)(π) values) and enhanced surfactant recovery during hysteresis experiments at χ(C18F) ≥ 0.30. The latter was attributed to the relatively rapid respreading rate of the perfluorinated amphiphile in comparison with DPPC alone at the air–water interface, which enhances the performance of this mixture as a potential pulmonary lung surfactant. Further, monolayer film structure could be tracked dynamically as a function of compression at the air–water interface via Brewster angle microscopy, with the C18F component being preferentially squeezed out of the film with compression, but returning rapidly upon re-expansion. In general, addition of C18F to DPPC monolayers resulted in improvements to mechanical, structural, and respreading properties of the film, indicating the potential value of these compounds as additives to pulmonary lung surfactant formulations.
由磷脂和全氟（或部分氟化）表面活性剂组成的单层表面活性剂膜在基于肺表面活性剂的肺治疗应用中具有潜在的用途。作为此类肺表面活性剂系统的简单最小模型，在简化的肺液模拟亚相（pH 7.4，150 mM NaCl）上制备的由 1,2-二棕榈酰-sn-甘油-3-磷酸胆碱（DPPC）和全氟十八烷酸（C18F）组成的二元混合单层膜在混合热力学和可压缩性（通过π-A 压缩等温线测量）、膜形态（通过原子力、荧光和布鲁斯特角显微镜）以及各种混合膜组成的重复扩展-收缩循环的扩展率和滞后响应方面进行了表征。在所有混合条件下，均发现膜及其组分完全不混溶和相分离，尽管膜性质随组成而发生重大变化。特别值得注意的是，在χ（C18F）≥0.30 时，不混溶性的程度（由ΔG（ex）（π）值表征）和滞后实验中表面活性剂回收的增强存在最大值。后者归因于全氟化两亲物在空气-水界面上相对于 DPPC 单独存在时相对较快的再扩展速率，这增强了该混合物作为潜在肺表面活性剂的性能。此外，通过布鲁斯特角显微镜可以动态跟踪单层膜结构作为空气-水界面压缩的函数，C18F 组分在压缩时优先从膜中挤出，但在重新扩展时迅速返回。一般来说，将 C18F 添加到 DPPC 单层中会改善膜的机械、结构和再扩展性能，表明这些化合物作为肺表面活性剂制剂添加剂的潜在价值。
