Department of Chemistry , University of Utah , 315 South 1400 East , Salt Lake City , Utah 84112-0850 , United States.
J Am Chem Soc. 2018 Mar 21;140(11):4071-4078. doi: 10.1021/jacs.7b13777. Epub 2018 Mar 9.
A common approach to exploring the structure and dynamics of biological membranes is through the deposition of model lipid bilayers on planar supports by Langmuir-trough or vesicle-fusion methods. Planar-supported lipid bilayers have been shown to exhibit structure and properties similar to those of lipid-vesicle membranes and are suitable for biosensing applications. Investigations using these planar-membrane models are limited to high-sensitivity methods capable of detecting a small population of molecules at the interface between a planar support and aqueous solution. In this work, we present evidence that supported-lipid bilayers can be deposited by vesicle fusion onto the interior surfaces throughout the wide-pore network of chromatographic silica particles. The thickness of a 1,2-dimyristoyl- sn-glycero-3-phosphocholine (DMPC) film and headgroup spacing are consistent with a single bilayer of DMPC deposited onto the pore surfaces. The high specific surface area of these materials generates phospholipid concentrations easily detected by confocal-Raman microscopy within an individual particle, which allows the structure of these supported bilayers to be investigated. Raman spectra of porous-silica-supported DMPC bilayers are equivalent to spectra of DMPC vesicle membranes, both above and below their melting phase transitions, suggesting comparable phospholipid organization and bilayer structure. These porous-silica-supported model membranes could share benefits that planar-supported lipid bilayers bring to biosensing applications, but in a material that overcomes the limited surface area of a planar support. To test this concept, the potential of these porous-silica-supported lipid bilayers as high-surface-area platforms for label-free Raman-scattering-based protein biosensing is demonstrated with detection of concanavalin A selectively binding to a lipid-immobilized mannose target.
一种探索生物膜结构和动力学的常用方法是通过Langmuir 槽或囊泡融合方法将模型脂质双层沉积在平面支撑物上。已证明平面支撑的脂质双层表现出与脂质囊泡膜相似的结构和性质，并且适合用于生物传感应用。使用这些平面膜模型的研究仅限于能够检测平面支撑物和水溶液界面处小部分分子的高灵敏度方法。在这项工作中，我们提供的证据表明，脂质双层可以通过囊泡融合沉积在整个宽孔网络的色谱硅胶颗粒的内表面上。1,2-二肉豆蔻酰- sn-甘油-3-磷酸胆碱 (DMPC) 膜的厚度和头部基团间距与沉积在孔表面上的单层 DMPC 一致。这些材料的高比表面积在单个颗粒内很容易通过共焦拉曼显微镜检测到磷脂浓度，从而可以研究这些支撑双层的结构。多孔硅胶支撑 DMPC 双层的拉曼光谱与 DMPC 囊泡膜的光谱等效，无论是在其熔融相变之上还是之下，这表明具有可比的磷脂组织和双层结构。这些多孔硅胶支撑的模型膜可以共享平面支撑脂质双层为生物传感应用带来的益处，但在克服了平面支撑物的有限表面积的材料中。为了验证这一概念，我们通过检测选择性结合到脂质固定化甘露糖靶标的伴刀豆球蛋白 A，证明了这些多孔硅胶支撑的脂质双层作为用于无标记拉曼散射的高表面积蛋白质生物传感平台的潜力。
