Abstract

The main component of pulmonary surfactant is dipalmitoyl phosphatidylcholine (DPPC), which reduces the surface tension almost to zero when the lung surface is compressed, thus preventing the alveolus from collapse in the course of exhalation. In this work the methods of the surface rheology have been employed to determine the influence of six pulmonary lipids on the dynamic surface properties of a DPPC monolayer at different temperatures and in a wide range of surface tensions. Particular attention has been paid to the region of low surface tensions (lower than 25 mN/m) at temperatures of 25 and 35°С, with these conditions being close to the physiological state on the internal surface of lungs. The addition of lipids with similar molecular structures to DPPC does not affect significantly the dynamic surface properties at a temperature of 25°C. At the same time, the addition of these lipids increases the surface elasticity in the region of low surface tensions at 35°С. However, under these conditions, the presence of lipids with unsaturated hydrocarbon radicals in the surface layer leads to the opposite effect and hinders the achievement of low surface tensions during slow compression. The results obtained have shown the possibility to control the properties of the lipid/DPPC mixed monolayer, which can be considered which can be considered as a model of pulmonary surfactant.

中文翻译：

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成分和温度对肺脂质混合单层动态特性的影响

摘要

肺表面活性物质的主要成分是二棕榈酰磷脂酰胆碱（DPPC），当肺表面受压时，其表面张力几乎为零，从而防止呼气过程中肺泡塌陷。在这项工作中，采用表面流变学方法来确定六种肺脂质在不同温度和广泛的表面张力下对 DPPC 单层动态表面特性的影响。特别关注温度为 25 和 35°С 时的低表面张力区域（低于 25 mN/m），这些条件接近肺内表面的生理状态。在DPPC中添加分子结构相似的脂质不会显着影响25℃温度下的动态表面性质。同时，这些脂质的添加增加了 35°С 低表面张力区域的表面弹性。然而，在这些条件下，表面层中具有不饱和烃基的脂质的存在会导致相反的效果，并阻碍在缓慢压缩过程中实现低表面张力。获得的结果表明可以控制脂质/DPPC混合单层的性质，可以将其视为肺表面活性剂的模型。