Kodama Akihisa T, Kuo Chin-Chang, Boatwright Thomas, Dennin Michael
Department of Physics & Astronomy, University of California, Irvine, California.
Department of Physics & Astronomy, University of California, Irvine, California.
Biophys J. 2014 Oct 7;107(7):1573-81. doi: 10.1016/j.bpj.2014.08.010.
We study the impact of the addition of particles of a range of sizes on the phase transition behavior of lung surfactant under compression. Charged particles ranging from micro- to nanoscale are deposited on lung surfactant films in a Langmuir trough. Surface area versus surface pressure isotherms and fluorescent microscope observations are utilized to determine changes in the phase transition behavior. We find that the deposition of particles close to 20 nm in diameter significantly impacts the coexistence of the liquid-condensed phase and liquid-expanded phase. This includes morphological changes of the liquid-condensed domains and the elimination of the squeeze-out phase in isotherms. Finally, a drastic increase of the domain fraction of the liquid-condensed phase can be observed for the deposition of 20-nm particles. As the particle size is increased, we observe a return to normal phase behavior. The net result is the observation of a critical particle size that may impact the functionality of the lung surfactant during respiration.
我们研究了添加一系列不同大小的颗粒对肺表面活性剂在压缩状态下相变行为的影响。从微米级到纳米级的带电颗粒沉积在朗缪尔槽中的肺表面活性剂薄膜上。利用表面积与表面压力等温线以及荧光显微镜观察来确定相变行为的变化。我们发现，直径接近20纳米的颗粒沉积会显著影响液晶相和液胀相的共存。这包括液晶域的形态变化以及等温线中挤出相的消除。最后，对于沉积20纳米颗粒的情况，可以观察到液晶相的域分数急剧增加。随着颗粒尺寸增大，我们观察到相变行为恢复正常。最终结果是观察到一个可能影响呼吸过程中肺表面活性剂功能的临界颗粒尺寸。
