| 초록 |
The cationic liposome-DNA complex has been an interesting subject in wide range of disciplines including gene therapy due to their highly ordered self-assembly. We have investigated a cationic lipid (DOTAP) and λ DNA complex monolayer at the air-water interface. The complex monolayer collapses to multilayers changing from an island domain to a two-dimensional network. From atomic force microscopy, the complexes transferred on a solid substrate appear as layer-by-layer stacks with a repetition height of about 4 nm. The fluorescent image with labeled λ DNA shows that each layer of the stack contains λ DNA molecules in between. Combined analysis with the microscopic images and x-ray reflectivity reveals that the repeated layer is a DNA monolayer sandwiched by two lipids monolayers, which is the same molecular alignment as the cationic liposome-DNA complexes in solutions. Several polyelectrolytes were also used and they showed different structures and phase behavior from the complexes with λ DNA. |
