Lipid rafts play a vital role in the function of cell membranes, including signal transduction, protein and lipid modification and optimization of protein function. The lipid raft hypothesis posits that phospholipids, in the presence of cholesterol and sphingolipids, can condense to form organized lipid domains known as “rafts.” The raft hypothesis has become a popular model among cell biologists to explain a variety of important cellular processes. However, investigating raft formation and function has proven to be challenging due to their transient nature and uncertainties regarding their size and composition. Many of these difficulties can be reduced or minimized by the deposition of thin lipid films on solid substrates which are more tractable for analysis. These multi-layer films, known as Langmuir-Blodgett (LB) films, can be successfully generated using many different combinations of membrane components. We worked on preparing a series of samples consisting of a number of lipid layers deposited on Indium Tin Oxide (ITO) float glass slides. One series of samples were based on simple lipids such as palmitic acid and the other on combinations of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1,2-dipalmitoyl-sn-glycerol-3-phosphocholine (DPPC) with cholesterol and sphingomyelin. With the membrane analogue essentially fixed in time and space, therefore, techniques such as time of flight secondary ion mass spectrometry (ToF-SIMS) can be used to image these ordered lipid domains in great detail.

Formation and characterization of Langmuir-Blodgett films of lipid rafts

249th National Meeting (2015)

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