Schürch S, Schürch D, Curstedt T, Robertson B
Respiratory Research Group, Faculty of Medicine, University of Calgary, Alberta, Canada.
J Appl Physiol (1985). 1994 Aug;77(2):974-86. doi: 10.1152/jappl.1994.77.2.974.
The physical properties of modified porcine surfactant (Curosurf), isolated from minced lungs by extraction with chloroform-methanol and further purified by liquid-gel chromatography, were investigated with the captive bubble technique. Bubble size, and thus the surface tension of an insoluble film at the bubble surface, is altered by changing the pressure within the closed bubble chamber. The film surface tension and area are determined from the shape (height and diameter) of the bubble. Adsorption of fresh Curosurf is characterized by stepwise decreases in surface tension, which can easily be observed by sudden quick movements of the bubble apex. These "adsorption clicks" imply a cooperative movement of large collective units of molecules, approximately 10(14) (corresponding to approximately 120 ng of phospholipid) or approximately 10(18) molecules/m2, into the interface during adsorption. Films formed in this manner are already highly enriched in dipalmitoyl phosphatidylcholine, as seen by the extremely low compressibility, close to that of dipalmitoyl phosphatidylcholine. Near-zero minimum tensions are obtained, even at phospholipid concentrations as low as 50 micrograms/ml. During dynamic cycling (20-50 cycles/min), low minimum surface tensions, good film stability, low compressibility, and maximum surface tensions between 30 and 40 mN/m are possible only if the films are not overcompressed near zero surface tension; i.e., the overall film area compression should not substantially exceed 30%.
通过氯仿 - 甲醇萃取从切碎的肺中分离并经液 - 凝胶色谱进一步纯化得到的改性猪表面活性剂（珂立苏）的物理性质，采用俘获气泡技术进行了研究。通过改变封闭气泡室内的压力，可以改变气泡大小，进而改变气泡表面不溶性薄膜的表面张力。薄膜的表面张力和面积由气泡的形状（高度和直径）确定。新鲜珂立苏的吸附表现为表面张力的逐步降低，这可以通过气泡顶端的突然快速移动很容易地观察到。这些“吸附喀哒声”意味着在吸附过程中，大约10¹⁴（相当于约120 ng磷脂）或约10¹⁸个分子/平方米的大分子集体单元协同移动到界面中。以这种方式形成的薄膜已经高度富含二棕榈酰磷脂酰胆碱，这从极低的压缩性可以看出，接近二棕榈酰磷脂酰胆碱的压缩性。即使在磷脂浓度低至50微克/毫升时，也能获得接近零的最小张力。在动态循环（20 - 50次循环/分钟）过程中，只有当薄膜在接近零表面张力时不过度压缩，即薄膜总面积压缩不应大幅超过30%，才可能实现低的最小表面张力、良好的薄膜稳定性、低压缩性以及30至40 mN/m之间的最大表面张力。
