Key points are not available for this paper at this time.
We observe quasistatic deformation of lipid vesicles from within, due to the polymerization of confined microtubules. A pair of long, narrow membrane sleeves appears, sheathing the microtubule ends as they grow. Spontaneous buckling reveals that the force generated can be greater than 2 pN. The evolution of shape and magnitude of force are consistent with a simple theory for the membrane free energy. We consider a model of the force generating mechanism in which thermal fluctuations of the membrane are ``rectified'' by the binding of tubulin dimers to the microtubule end.
Fygenson et al. (Mon,) studied this question.