ABSTRACT
The intricate nature of the cellular cortex and the inevitable presence of cytosolic components and organelles, in particular the nucleus, often prevents a quantitative assessment of the cell elastic properties. Model membranes were frequently employed to reduce complexity, while still capturing the essential physical properties of the plasma membrane. Giant unilamellar vesicles (GUVs) have proven to be among the most versatile model membranes to mimic the plasma membrane cortex and investigate the mechanical properties of cells. Atomic force microscopy not only permits obtaining high resolution topographic images of surfaces but also allows exerting and measuring forces ranging from few pico-newtons to several micro-newtons at defined spots. These experiments generate so-called force-indentation curves that can be interpreted in terms of stress-strain relationships accounting for the geometry of indenter and sample. This gives access to mechanical aspects such as bending moduli, area compressibility, pre-stress and lysis tension. This chapter describes indentation and compression experiments on adherent GUVs, providing also simple solutions to infer membrane elasticity.
