Nuclear-spin relaxation induced by shape fluctuations in membrane vesicles.
Nuclear-spin relaxation rates resulting from shape fluctuations of unilamellar quasispherical vesicles are calculated. We show that in the kHz range these fluctuations yield-in contrast to previous conclusions on planar membranes - a relaxation rate proportional to the inverse Larmor frequency and provide direct information on the bending rigidity of membranes.