A comparison of detergent action on supported lipid monolayers and bilayers

Abstract

Using spatially patterned supported lipid mono- and bilayers, we compare the effect of transleaflet dynamics on membrane solubilization by a common, non-ionic detergent in single samples. We find that at concentrations surrounding CMC, complete bilayers undergo 5–8% lateral expansion followed by rapid dissolution. In contrast, single supported monolayers remain remarkably resistant to solubilization, suggesting the central role of detergent or lipid flip-flop in driving membrane solubilization. In addition to the previously well-appreciated mode of detergent-resistance by tight lateral packing of saturated and cholesterol-rich lipids (e.g., rafts) in membrane bilayers, our results suggest that hindrance to interleaflet dynamics, such as by strong interaction with the cytoskeleton, provides an alternative mechanism by which membranes resist detergent solubilisation. Furthermore, we show that this differential resistance can be exploited to design spatial compositional patterns of lipid bilayers and monolayers.