Effective-area elasticity and tension of micromanipulated membranes

We evaluate the effective Hamiltonian governing, at the optically resolved scale. tile elastic properties of micromanipulated membranes. We identify f loppy, entropic-tense and stretched-tense regimes, representing different b ehaviors of the effective-area elasticity of the membrane. The correspondin g effective tension depends on the microscopic parameters (total area, bend ing rigidity) and on the optically visible area, which is controlled by the imposed external constraints. We successfully compare our predictions with recent data on micropipette experiments.