Effects of a pulling force on the shape of a bound vesicle

We develop a theoretical model to describe the vertical pulling of vesicles adhered in a contact potential. For a range of applied forces, locally stable bound shapes, separated from the free shape by an energy barrier, can be found. The phase diagram contains regions with either a unique bound shape or an additional meta-stable shape. Upon pulling, these shapes unbind discontinuously since the vesicles disengage from the substrate while still possessing a finite adhesion area.