Bachofen H, Gerber U, Gehr P, Amrein M, Schürch S
Division of Pneumology, University Hospital of Berne, 3010 Berne, Switzerland.
Biochim Biophys Acta. 2005 Dec 30;1720(1-2):59-72. doi: 10.1016/j.bbamem.2005.11.007. Epub 2005 Dec 9.
Phospholipid films can be preserved in vitro when adsorbed to a solidifiable hypophase. Suspensions of natural surfactant, lipid extract surfactants, and artificial surfactants were added to a sodium alginate solution and filled into a captive bubble surfactometer (CBS). Surfactant film was formed by adsorption to the bubble of the CBS for functional tests. There were no discernible differences in adsorption, film compressibility or minimal surface tension on quasi-static or dynamic compression for films formed in the presence or absence of alginate in the subphase of the bubble. The hypophase-film complex was solidified by adding calcium ions to the suspension with the alginate. The preparations were stained with osmium tetroxide and uranyl acetate for transmission electron microscopy. The most noteworthy findings are: (1) Surfactants do adsorb to the surface of the bubble and form osmiophilic lining layers. Pure DPPC films could not be visualized. (2) A distinct structure of a particular surfactant film depends on the composition and the concentration of surfactant in the bulk phase, and on whether or not the films are compressed after their formation. The films appear heterogeneous, and frequent vesicular and multi-lamellar film segments are seen associated with the interfacial films. These features are seen already upon film formation by adsorption, but multi-lamellar segments are more frequent after film compression. (3) The rate of film formation, its compressibility, and the minimum surface tension achieved on film compression appear to be related to the film structure formed on adsorption, which in turn is related to the concentration of the surfactant suspension from which the film is formed. The osmiophilic surface associated surfactant material seen is likely important for the surface properties and the mechanical stability of the surfactant film at the air-fluid interface.
当磷脂膜吸附到可固化的下相时，可在体外保存。将天然表面活性剂、脂质提取物表面活性剂和人工表面活性剂的悬浮液添加到海藻酸钠溶液中，并填充到俘获气泡表面张力仪（CBS）中。通过吸附到CBS的气泡上形成表面活性剂膜以进行功能测试。在气泡下相存在或不存在海藻酸盐的情况下形成的膜，在准静态或动态压缩时，其吸附、膜压缩性或最小表面张力没有明显差异。通过向含有海藻酸盐的悬浮液中添加钙离子来固化下相 - 膜复合物。将制剂用四氧化锇和醋酸铀酰染色以进行透射电子显微镜检查。最值得注意的发现是：（1）表面活性剂确实吸附到气泡表面并形成亲锇内衬层。纯二棕榈酰磷脂酰胆碱（DPPC）膜无法可视化。（2）特定表面活性剂膜的独特结构取决于本体相中表面活性剂的组成和浓度，以及膜形成后是否被压缩。膜看起来是不均匀的，并且经常看到与界面膜相关的囊泡状和多层膜片段。这些特征在通过吸附形成膜时就已出现，但多层片段在膜压缩后更频繁。（3）膜形成的速率、其压缩性以及膜压缩时达到的最小表面张力似乎与吸附时形成的膜结构有关，而膜结构又与形成膜的表面活性剂悬浮液的浓度有关。所观察到的亲锇表面相关的表面活性剂材料可能对表面活性剂膜在气 - 液界面的表面性质和机械稳定性很重要。
