Probing the dynamics of planar supported membranes by Nile red fluorescence lifetime distribution

The structure and dynamics of planar supported membranes were studied by using the fluorescence probe Nile red. The width of fluorescence lifetime distribution of Nile red was used to infer the heterogeneity of membranes. The width of fluorescence lifetime was larger and the lifetime was shorter in supported membranes when compared to vesicle membranes. This was interpreted as due to the presence of water-filled membrane discontinuity leading to a heterogeneous surface in supported membranes. Microdomain causing agents such as cholesterol, sphingomyelin, etc. caused a larger level of heterogeneity in supported membranes when compared to vesicle membranes.