Alonso Coralie, Waring Alan, Zasadzinski Joseph A
Department of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, USA.
Biophys J. 2005 Jul;89(1):266-73. doi: 10.1529/biophysj.104.052092. Epub 2005 Apr 15.
Lung surfactant causes the surface tension, gamma, in the alveoli to drop to nearly zero on exhalation; in the upper airways gamma is approximately 30 mN/m and constant. Hence, a surface tension gradient exists between alveoli and airways that should lead to surfactant flow out of the alveoli and elimination of the surface tension gradient. However, the lung surfactant specific protein SP-C enhances the resistance to surfactant flow by regulating the ratio of solid to fluid phase in the monolayer, leading to a jamming transition at which the monolayer transforms from fluidlike to solidlike. The accompanying three orders of magnitude increase in surface viscosity helps minimize surfactant flow to the airways and likely stabilizes the alveoli against collapse.
肺表面活性剂可使肺泡内的表面张力γ在呼气时降至几乎为零；在上呼吸道，γ约为30 mN/m且保持恒定。因此，肺泡和气道之间存在表面张力梯度，这会导致表面活性剂从肺泡流出并消除表面张力梯度。然而，肺表面活性剂特异性蛋白SP-C通过调节单分子层中固相与液相的比例来增强对表面活性剂流动的阻力，从而导致单分子层发生堵塞转变，即从类流体状态转变为类固体状态。随之而来的表面粘度增加三个数量级，有助于将表面活性剂流向气道的情况降至最低，并可能稳定肺泡以防止塌陷。
