Liu Xianhe, Counil Claire, Shi Da, Mendoza-Ortega Estefania E, Vela-Gonzalez Andrea V, Maestro Armando, Campbell Richard A, Krafft Marie Pierre
University of Strasbourg, Institut Charles Sadron (CNRS), 23 rue du Loess, 67034 Strasbourg Cedex, France.
Institut Laue-Langevin, 71 Avenue des Martyrs, CS20156, 38042 Grenoble Cedex 9, France.
J Colloid Interface Sci. 2021 Jul;593:1-10. doi: 10.1016/j.jcis.2021.02.073. Epub 2021 Mar 4.
Fluorocarbon gases introduced above monolayers of phospholipids at the air/water interface were recently found to promote the adsorption of diverse molecular compounds, with potential application in drug-loaded microbubble design. Quantitative determination of the fluorocarbon present in the monolayers is strongly needed for the development of such applications. We hypothesized that neutron reflectometry (NR) and ellipsometry experiments would allow quantification of the fluorocarbon trapped in the monolayers.
We report the first quantitative determination of the extents of adsorption of perfluorohexane (F-hexane) on different phospholipid monolayers with respect to both their phase and isotopic form. To this aim, we applied an approach based on co-modeling the data obtained from NR and ellipsometry.
We found that F-hexane adsorbs strongly in monolayers of dipalmitoylphosphatidylcholine (DPPC) when they are both in the liquid expanded (LE) and liquid condensed (LC) phases, but to different extents according to the isotopic form of the phospholipid. Kinetic resolution of the interfacial composition from data on both isotopic contrasts (assuming chemical identicality) was therefore not possible using NR alone, so an alternative NR/ellipsometry co-modeling treatment was applied to data from each isotopic contrast. F-hexane adsorbs more abundantly on monolayers of hydrogenous DPPC than chain-deuterated DPPC when they are in the LE phase, whilst the opposite was observed when they monolayers are in the LC phase. The extents of adsorption of F-hexane in monolayers of dimyristoylphosphatidylcholine (DMPC, LE phase) and distearoylphosphatidylcholine (DSPC, LC phase) concurs with the strong dependence of those with phospholipids of different isotopic contrasts according to the monolayer phase. This new methodology can lead to advances in the novel characterization of fluorocarbons interacting with phospholipid monolayers of relevance to applications such as in the shells of fluorocarbon-stabilized medically-oriented microbubbles.
最近发现，在空气/水界面的磷脂单分子层上方引入的碳氟化合物气体可促进多种分子化合物的吸附，在载药微泡设计中有潜在应用。对于此类应用的开发，迫切需要对单分子层中存在的碳氟化合物进行定量测定。我们假设中子反射率（NR）和椭偏测量实验能够对捕获在单分子层中的碳氟化合物进行定量。
我们首次定量测定了全氟己烷（F - 己烷）在不同磷脂单分子层上的吸附程度，涉及它们的相态和同位素形式。为此，我们采用了一种基于对NR和椭偏测量获得的数据进行联合建模的方法。
我们发现，当二棕榈酰磷脂酰胆碱（DPPC）单分子层处于液晶态扩展（LE）相和液晶态凝聚（LC）相时，F - 己烷都能强烈吸附，但根据磷脂的同位素形式，吸附程度不同。因此，仅使用NR无法从两种同位素对比的数据（假设化学性质相同）中对界面组成进行动力学解析，所以对每种同位素对比的数据应用了另一种NR/椭偏测量联合建模处理方法。当处于LE相时，F - 己烷在含氢DPPC单分子层上的吸附量比链氘代DPPC单分子层上的吸附量更多，而当单分子层处于LC相时，观察到的情况则相反。F - 己烷在二肉豆蔻酰磷脂酰胆碱（DMPC，LE相）和二硬脂酰磷脂酰胆碱（DSPC，LC相）单分子层上的吸附程度与那些根据单分子层相态具有不同同位素对比的磷脂的吸附程度密切相关。这种新方法可推动与碳氟化合物相互作用的磷脂单分子层新表征的进展，这些相互作用与诸如碳氟化合物稳定的医学导向微泡壳等应用相关。
