Liquidlike structures in dilute suspensions of charged liposomes

Electrostatically stabilized aqueous dispersions of both slightly and highly charged liposomes have been analyzed by quasielastic light scattering. The obtained static structure factor S(q) revealed a liquidlike ordering due to long range electrostatic interactions. The fit of S(q) assuming a Derjaguin-Landau-Verwey-Overbeek interaction potential within the Debye-Huckel approximation, the Ornstein-Zernike equation and the hypernetted chain approximation, as a closure relation, allowed obtaining an effective charge value. Simultaneously, alternative charge values were estimated from electrophoretic measurements, turning out to be very close to the effective ones. This study also suggests that the charge seems to be unequally distributed over the vesicles in the case of liposomes formed by mixtures of charged and uncharged lipids. Size polydispersity was also considered. (C) 2003 American Institute of Physics.