Department of Applied Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura, Saitama 338-8570, Japan.
J Chem Phys. 2019 Jul 14;151(2):025102. doi: 10.1063/1.5103221.
Understanding the effect of a solid support on the dynamical properties of a supported lipid bilayer (SLB) is a prerequisite for the applications of SLB as a model biomembrane. Here, we applied two-dimensional fluorescence lifetime correlation spectroscopy to examine the effect of solution pH on the diffusion of lipids in the proximal/distal leaflets of a zwitterionic SLB. Leaflet-specific diffusion analyses at various pH revealed that the diffusion of lipids in the proximal leaflet facing a glass surface becomes slower by decreasing pH with the transition pH of ∼7.4. We attributed it to the reduction of the surface charge density of a glass support. Furthermore, the data clearly showed that the lipid diffusion in the distal leaflet facing a bulk solution is insensitive to the change in the diffusion property of the proximal leaflet. This reflects a weak interleaflet coupling between the proximal and distal leaflets of the SLB.
了解固体支撑对支撑脂质双层（SLB）动力学性质的影响是将 SLB 作为模型生物膜应用的前提。在这里，我们应用二维荧光寿命相关光谱来研究溶液 pH 值对离子型 SLB 近/远小叶中脂质扩散的影响。在不同 pH 值下的小叶特异性扩散分析表明，随着 pH 值降低至约 7.4，面向玻璃表面的近小叶中脂质的扩散速度变慢。我们将其归因于玻璃支撑物表面电荷密度的降低。此外，数据清楚地表明，面向体相溶液的远小叶中脂质的扩散对近小叶扩散性质的变化不敏感。这反映了 SLB 的近小叶和远小叶之间的弱层间耦合。
