Chemical processes occurring at phospholipid membranes play a critical role in a wide range of biologically relevant process such as enzyme regulation, immune response, mediation of small molecule uptake into cells, and cell signaling and adhesion. Typical methods for analysis which attempt to probe bilayer structure and molecular interactions at model phospholipid membranes have employed dispersions of phospholipid vesicles or planar supported model phospholipid membranes. Vesicle dispersion methods are typically limited by high backgrounds from free-solution analyte, and single-vesicle methods require difficult optical trapping techniques, while planar supported bilayer experiments suffer from poor signal-to-noise arising from the small number of phospholipid molecules in the detection area and typically require fluorescently labeled-targets. Here we present an approach to address these limitations: deposition of supported phospholipid bilayers on the surfaces of the pore network of large-pore (30-100nm) chromatographic silica particles. These supported bilayers are compatible with confocal Raman microscopy in a two of label-free experiments that will be presented: detection and quantification of Concanavalin A lectin interaction with bilayer localized mannose and measurement of equilibrium populations of a lipid-bilayer associated signal peptide, glucagon-like peptide 1 (GLP-1) . Given the sensitivity of the Raman spectra to lipid-membrane structure, these experiments also provide insight into structural changes which occur in the phospholipid bilayer and membrane-interacting biomolecules.

Confocal-Raman microscopy of phospholipid bilayers in small-volume, high surface area supports: An informative tool for investigating bilayer-analyte interactions

256th National Meeting (2018)

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