Amphiphile-induced spherical microexovesicle corresponds to an extreme local area difference between two monolayers of the membrane bilayer.

It is shown that an increase of the area difference between the outer and the inner membrane lipid layers of the skeleton-free membrane segment as a result of exogenously added amphiphilic molecules results in budding of the segment. The process reaches its final point when the segment attains the shape of the local maximal area difference, corresponding to formation of a spherical microexovesicle.