School of Mechanical and Mechatronic Engineering, University of Technology Sydney, 81 Broadway, Ultimo, NSW 2007, Australia.
Phys Chem Chem Phys. 2020 Jul 21;22(27):15231-15241. doi: 10.1039/d0cp00268b. Epub 2020 Jul 1.
Lung surfactant (LS) monolayers that continuously expand and compress during breathing cycles, act as the first line barrier for inhaled nanoparticles. It is known that nanoparticles which adsorb to the surface of the surfactant layer facilitate the rearrangement of lipids and peptides at various stages of the breathing cycle. However, the structural mechanisms for this ability of the lipid rearrangement are not yet fully understood. Coarse-grained molecular dynamics simulations are performed to investigate the role of surfactant protein B (SP-B) segments (SP-B) in modulating the biophysical properties of the surfactant monolayer in the presence of polydisperse gold nanoparticles (AuNPs) at different concentrations. Herein, we observe that the AuNPs significantly alter the inherent structural and dynamical properties of the monolayer and its components in three different breathing states. When adsorbed into the monolayer, the AuNPs inhibit the ability of the monolayer to recover its surface tension and other properties. The presence of SP-B in the monolayer accelerates the diffusion of the monolayer phospholipids, contrarily to the role of AuNPs on phospholipid diffusion. Also, the AuNPs and the peptides in the monolayer significantly increase their agglomeration in the presence of one another. Overall, the simulations predict that the presence of polydisperse AuNPs hampers the stability and biophysical functions of the LS in contrast to the role of the peptide. This study provides a clear view of the hydrophobic peptide role in the LS monolayer at the interface along with the interactions and the translocation of AuNPs that could have a significant impact to assess the NPs inhalation.
肺表面活性剂 (LS) 单层在呼吸循环中不断扩张和压缩，充当吸入纳米颗粒的第一道屏障。已知吸附在表面活性剂层表面的纳米颗粒促进了在呼吸循环的各个阶段脂质和肽的重新排列。然而，这种脂质重排能力的结构机制尚不完全清楚。进行粗粒度分子动力学模拟，以研究在不同浓度的多分散金纳米颗粒 (AuNPs) 存在下，表面活性蛋白 B (SP-B) 片段 (SP-B) 在调节表面活性剂单层的生物物理特性中的作用。在这里，我们观察到 AuNPs 显着改变了单层及其成分在三种不同呼吸状态下的固有结构和动力学特性。当吸附到单层中时，AuNPs 抑制了单层恢复其表面张力和其他性质的能力。SP-B 的存在加速了单层磷脂的扩散，与 AuNPs 对磷脂扩散的作用相反。此外，在存在彼此的情况下，AuNPs 和单层中的肽显着增加了它们的聚集。总体而言，模拟预测，与肽的作用相反，多分散 AuNPs 的存在会阻碍 LS 的稳定性和生物物理功能。本研究清楚地说明了疏水性肽在 LS 单层界面上的作用以及 AuNPs 的相互作用和易位，这可能对评估 NPs 的吸入有重大影响。
