Fluid mechanics at the cellular membrane*

The mechanical and chemical interactions between cells and their surroundings dictate their behavior, such as motion, growth, and proliferation. Such interactions are mediated by the cell’s membrane, a thin layer composed of a lipid bilayer and embedded proteins. The membrane’s functions include the transport of molecules and ions, and sensing (or signaling); therefore, it is crucial for homeostasis, or the maintenance of a stable internal state. Controlled studies into membrane mechanics have been limited by complexities in geometry and detection of forces at the scale of pico-Newtons. To address these challenges, we use novel force measurement techniques with optical tweezers to probe the hydrodynamic flow around free-standing lipid bilayers within microfluidic channels. The aims of these measurements are to quantify the interfacial tension of lipid bilayers and fluid slip close to the layer surface, building towards a fundamental understanding of the physical principle governing the hydrodynamics around membranes.