Encapsulation of DNA in new multilamellar vesicles prepared by shearing a lyotropic lamellar phase.

Encapsulation of DNA in a new non-cationic multilamellar vector (Spherulites), composed of phosphatidylcholine, cholesterol and polyoxyethylene alcohol, is described here for the first time. Spherulites entrapping DNA were prepared by shearing a phospholipid lyotropic lamellar phase, using a recently discovered method. The average diameter of these vesicles ranges around 300 nm, and can be adjusted depending on the conditions of the process. The formulation did not result in cytotoxicity for the human cells and could be used as a DNA delivery system. More emphasis is brought to the role of condensing agents like histones on the encapsulation yield, which has been studied using radiolabelled DNA. It is shown that use of histones (histone to DNA ratio of 0.4) can increase significantly the encapsulation of DNA, thus improving the transfection efficiency. Transfection experiments were done with success using the beta-galactoside reporter gene on human primary cells (human skin fibroblasts and human bone marrow stromal cells). The results suggest that the spherulites have to be considered as a new and promising tool for gene transfection.