Interactions between supported lipid bilayers and substrates that affect lateral diffusion of lipids

Changes in the diffusion coefficient of supported lipid bilayers affected by their interaction with the substrate were evaluated by fluorescence recovery after photobleaching under different surface charges and ambient conditions (presence of divalent ions in solution). The diffusion coefficients of each leaflet were estimated separately by quenching only the leaflet on the far side from the substrate with Co2+ ions. The potential valleys, which are created by the divalent ions between the supported lipid bilayer and the substrate or the positive charges on the substrate surface, act as diffusion barriers, and the diffusion coefficient of the leaflet on the side closer to the substrate decreases. At the same time, the other leaflet far from the substrate also showed a somewhat decrease in diffusion coefficient due to interleaflet coupling.