Investigating the effects of membrane tension and shear stress on lipid domains in model membranes

We present a method to apply different forces to model membranes using microfluidic technology. Giant unilamellar vesicles (GUVs) were biochemically immobilized within a multilayer chip using a cholesterol linker. A deformable PDMS membrane allows the application of mechanical pressure to the vesicles. Furthermore, using the laminar flow within the microchannels, shear stress can be applied. To study the effects these forces have on lipid rafts, we used GUVs with phase-separated domains as model and made observations using confocal microscopy. The results indicate that prolonged pressure, and hence increased membrane tension, alters the patterns of the domains. Moreover, the device permits monitoring of domain reorganization after disruption by shear stress. This approach opens up the possibility of studying the effects of simultaneous forces, not only on model membranes but on whole cells.