文摘
Liposome consisting of a single zwitterionic lipid as the potential vector for gene therapy has been reportedrecently; however, whether polyanionic DNA can bind directly with zwitterionic lipid without the aid ofmultivalent salt still remains unresolved. In this study, we reveal the aggregation of zwitterionic oligolamellarliposomes composed of 1,2-di(cis-9-octadecenoyl)-sn-glycero-3-phosphocholine induced by DNA withoutthe presence of multivalent salt. Our results demonstrate that only a small fraction (<10%) of DNA canbind electrostatically with a portion of the liposomes. Such a low degree of binding, however, inducessignificant aggregation of these oligolamellar liposomes, yielding large multilamellar particles in which thenumber of hydrophilic/hydrophobic layer stacking becomes sufficiently large to yield multiple diffractionpeaks in the small-angle X-ray scattering profile. Addition of monovalent salt such as NaCl tends to disruptthe multilamellar structure.