CHARACTERIZATION OF VESICLES BY CLASSICAL LIGHT-SCATTERING

Classical, or static, light scattering techniques can be used to determine the geometric size, shape, apparent molecular weight, and radius of gyration of phosphatidylcholine vesicles in aqueous suspension. A Rayleigh-Gans-Debye (RGD) analysis of multiangle scattered light intensity data yields the size and degree of polydispersity of the vesicles in solution, while the Zimm plot technique provides the radius of gyration and apparent weight-average molecular weight. Together RGD theory and Zimm plots can be used to confirm the geometric shape of vesicles. Vesicles varying from 65 to 90 nm in diameter have been characterized effectively. The static light scattering measurements indicate that, as expected, phosphatidylcholine vesicles in this size range scatter light as isotropic hollow spheres. This dual treatment of the static light scattering data also provides an internal, self-consistent check of the vesicle size determination. The values for geometric radii determined by classical light scattering typically agree with those estimated by dynamic light scattering to within a few percent. © 1991.