Universality of DNA adsorption behavior on the cationic membranes of nanolipoplexes

Nanolipoplexes have emerged worldwide as the most prevalent synthetic gene delivery system. Nowadays, it is accepted that complete DNA protection and a precise control of the physical attributes of emerging complexes are major steps toward rational design of efficient nanocarriers. Here we revise the mechanism of DNA adsorption to the cationic membranes of lipid nanovectors. Here we show that both the DNA-binding ability of cationic membranes and the one-dimensional DNA packing density inside the complex depend on the cationic lipid/anionic DNA charge ratio. Remarkably, both these distributions are rescaled on universal curves when plotted against gamma, a dimensionless quantity expressing the ratio between the area of cationic membranes and that occupied by DNA molecules. As a result, the DNA condensation on the surface of lipid nanocarriers can be regarded as a two-step process. Our findings indicate a successful way to the rational design of next-generation drug delivery nanocarriers.