Jordan Luke R, Blauch Megan E, Baxter Ashley M, Cawley Jennie L, Wittenberg Nathan J
Department of Chemistry, Lehigh University, 6 East Packer Avenue, Bethlehem, PA, 18015, USA.
Department of Chemistry, Lehigh University, 6 East Packer Avenue, Bethlehem, PA, 18015, USA.
Colloids Surf B Biointerfaces. 2019 Nov 1;183:110442. doi: 10.1016/j.colsurfb.2019.110442. Epub 2019 Aug 16.
Gangliosides are glycolipids that are enriched on the outer surface of cell membranes. Gangliosides are receptors for a number of signaling molecules and toxins, and therefore are often incorporated into biosensors. Many of these biosensors incorporate gangliosides into supported lipid bilayers which are formed by the spontaneous rupture of unilamellar vesicles on glass or SiO substrates. In this work, we used quartz crystal microbalance with dissipation monitoring (QCM-D) to investigate how the presence of the four major brain gangliosides (GM1, GD1a, GD1b, and GT1b) influences the process of supported lipid bilayer formation on SiO surfaces. We show that the rate of supported bilayer formation is dependent on both the charge and position of sialic acid moieties on ganglioside molecules. Additionally, Ca can accelerate ganglioside-rich supported bilayer formation, but the degree of acceleration differs for vesicles containing different gangliosides. Fluorescence recovery after photobleaching measurements show that the presence of all gangliosides reduces lipid diffusion coefficients in a concentration-dependent manner, and that Ca slows lipid diffusion in membranes with and without gangliosides. Finally, we use ganglioside-rich supported bilayers to measure binding constants for a GD1a-binding antibody that has similar properties to antibodies present in a variant of Guillain-Barré syndrome.
神经节苷脂是一种糖脂，在细胞膜外表面富集。神经节苷脂是多种信号分子和毒素的受体，因此常被纳入生物传感器中。许多这类生物传感器将神经节苷脂纳入支撑脂质双层中，支撑脂质双层是由单层囊泡在玻璃或二氧化硅基质上自发破裂形成的。在这项工作中，我们使用具有耗散监测功能的石英晶体微天平（QCM-D）来研究四种主要脑源性神经节苷脂（GM1、GD1a、GD1b和GT1b）的存在如何影响二氧化硅表面支撑脂质双层的形成过程。我们表明，支撑双层的形成速率取决于神经节苷脂分子上唾液酸部分的电荷和位置。此外，钙离子可以加速富含神经节苷脂的支撑双层的形成，但对于含有不同神经节苷脂的囊泡，加速程度有所不同。光漂白后荧光恢复测量表明，所有神经节苷脂的存在均以浓度依赖的方式降低脂质扩散系数，并且钙离子会减缓有或没有神经节苷脂的膜中的脂质扩散。最后，我们使用富含神经节苷脂的支撑双层来测量一种与格林-巴利综合征变体中存在的抗体具有相似特性的GD1a结合抗体的结合常数。
