Coupling supported lipid bilayer electrophoresis with matrix-assisted laser desorption/ionization-mass spectrometry imaging

Herein, we describe a new analytical platform utilizing advances in heterogeneous supported lipid bilayer (SLB) electrophoresis and matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) imaging. This platform allowed for the separation and visualization of both charged and neutral lipid membrane components without the need for extrinsic labels. A heterogeneous SLB was created using vesicles containing monosialoganglioside GM1, disialoganglioside GD1b, POPC, as well as the ortho and para isomers of Texas Red-DHPE. These components were then separated electrophoretically into five resolved bands. This represents the most complex separation by SLB electrophoresis performed to date. The SLB samples were flash frozen in liquid ethane and dried under vacuum before imaging with MALDI-MS. Fluorescence microscopy was employed to confirm the position of the Texas Red labeled lipids, which agreed well with the MALDI-MS imaging results. These results clearly demonstrate this platform's ability to isolate and identify nonlabeled membrane components within an SLB.