Passive and reversible area regulation of supported lipid bilayers in response to fluid flow

Biological and model membranes are frequently subjected to fluid shear stress. However, membrane mechanical responses to flow remain incompletely described. This is particularly true of membranes supported on a solid substrate, and the influences of membrane composition and substrate roughness on membrane flow responses remain poorly understood. Here, we combine microfluidics, fluorescence microscopy, and neutron reflectivity to explore how supported lipid bilayer patches respond to controlled shear stress. We demonstrate that lipid membranes undergo a significant, passive, and partially reversible increase in membrane area due to flow. We show that these fluctuations in membrane area can be constrained, but not pre-vented, by increasing substrate roughness. Similar flow-induced changes to membrane structure may contribute to the ability of living cells to sense and respond to flow.

Automated summary

This study investigates the mechanical responses of lipid membranes to fluid shear stress, especially those supported on solid substrates. The effects of membrane composition and substrate roughness on membrane flow responses are poorly understood. By using microfluidics, fluorescence microscopy, and neutron reflectivity, the researchers demonstrate that lipid membranes undergo a significant, passive, and partially reversible increase in membrane area due to flow. Increasing substrate roughness can limit but not prevent the fluctuations in membrane area. These flow-induced changes in membrane structure may be important for cells to sense and respond to flow.