Huygens-Kamerlingh Onnes Lab, Universiteit Leiden, P.O. Box 9504, 2300 RA Leiden, The Netherlands.
Soft Matter. 2019 Feb 6;15(6):1345-1360. doi: 10.1039/c8sm01661e.
The use of colloid supported lipid bilayers (CSLBs) has recently been extended to create colloidal joints, that enable the assembly of structures with internal degrees of flexibility, and to study lipid membranes on curved and closed geometries. These novel applications of CSLBs rely on previously unappreciated properties: the simultaneous fluidity of the bilayer, lateral mobility of inserted (linker) molecules and colloidal stability. Here we characterize every step in the manufacturing of CSLBs in view of these requirements using confocal microscopy and fluorescence recovery after photobleaching (FRAP). Specifically, we have studied the influence of different particle properties (roughness, surface charge, chemical composition, polymer coating) on the quality and mobility of the supported bilayer. We find that the insertion of lipopolymers in the bilayer can affect its homogeneity and fluidity. We improve the colloidal stability by inserting lipopolymers or double-stranded inert DNA into the bilayer. We include surface-mobile DNA linkers and use FRAP to characterize their lateral mobility both in their freely diffusive and bonded state. Finally, we demonstrate the self-assembly of flexibly linked structures from the CSLBs modified with surface-mobile DNA linkers. Our work offers a collection of experimental tools for working with CSLBs in applications ranging from controlled bottom-up self-assembly to model membrane studies.
胶体支撑的脂质双层（CSLB）的使用最近已经扩展到创建胶体连接，使具有内部柔韧性的结构的组装成为可能，并研究弯曲和封闭几何形状上的脂质膜。CSLB 的这些新应用依赖于以前未被重视的性质：双层的同时流动性、插入的（连接）分子的横向流动性和胶体稳定性。在这里，我们使用共焦显微镜和光漂白后荧光恢复（FRAP）来研究制造 CSLB 的每一步，以满足这些要求。具体来说，我们研究了不同颗粒特性（粗糙度、表面电荷、化学组成、聚合物涂层）对支撑双层的质量和流动性的影响。我们发现，双层中插入的脂多糖会影响其均一性和流动性。我们通过将脂多糖或双链惰性 DNA 插入双层来提高胶体稳定性。我们包括表面可移动的 DNA 连接子，并使用 FRAP 来表征它们在自由扩散和键合状态下的横向流动性。最后，我们展示了通过表面可移动 DNA 连接子修饰的 CSLB 自组装的灵活连接结构。我们的工作为 CSLB 在从受控的自下而上的自组装到模型膜研究的各种应用中提供了一系列实验工具。
