Faculty of Chemistry, Biological and Chemical Research Centre , University of Warsaw , Żwirki i Wigury 101 , 02-089 Warsaw , Poland.
Langmuir. 2019 Jul 23;35(29):9422-9429. doi: 10.1021/acs.langmuir.9b01311. Epub 2019 Jul 10.
Floating lipid bilayers composed of phosphatidylglycerols and cardiolipin were deposited on gold electrodes premodified with 1-thio-β-d-glucose monolayer by spreading of small unilamellar vesicles. The resulting lipid membrane was homogeneous, and its thickness was ∼5.0 nm. Electrochemical characterization combined with surface-enhanced infrared absorption spectroscopy revealed that negative polarization of the electrode leads to accumulation of water molecules in the interfacial region between lipid membrane and the thioglucose film. Moreover, the buildup of water layer was demonstrated to affect the nanomechanical properties of the membrane. The latter was manifested by well-pronounced decrease of Young's modulus of the lipid bilayer correlating with increasing hydration. This effect was ascribed to the decoupling of the membrane from supporting thioglucose film due to the accumulation of interfacial water. As a result, the effective stiffness of the supporting layer is lower and it alters the nanomechanical behavior of lipid membrane. Our results provide strong experimental proof for the correlation between elastic properties of floating lipid membrane and the amount of water accumulated in the submembrane region.
由磷脂酰甘油和心磷脂组成的浮动脂质双层通过小单层囊泡的铺展沉积在预先用 1-硫代-β-d-葡萄糖单层修饰的金电极上。所得脂质膜是均匀的，其厚度约为 5.0nm。电化学表征结合表面增强红外吸收光谱表明，电极的负极化导致脂质膜和硫葡萄糖膜之间的界面区域水分子的积累。此外，水层的形成被证明会影响膜的纳米力学性质。后者表现为脂质双层的杨氏模量明显降低，与水合作用的增加相关。这种效应归因于由于界面水的积累，膜与支撑的硫葡萄糖膜解耦。结果，支撑层的有效刚度降低，改变了脂质膜的纳米力学行为。我们的结果为浮动脂质膜的弹性性质与亚膜区域积累的水量之间的相关性提供了强有力的实验证据。
