Characterisation and stability of lipid–DNA complexes

A combination of complementary analytical techniques has provided valuable information on the physicochemical properties of lipid–DNA complexes such as their size, shape, structure and surface charge. The experimental conditions for producing small and stable lipid–DNA complexes were determined. These complexes consist of spherical primary particles of approximately 60 nm in diameter connected to each other by DNA strands to form small clusters of approximately 70–200 nm in diameter. At high salt concentrations these complexes were not stable and aggregated. Several methods were used to stabilise the lipid–DNA complexes at physiological salt concentrations.