Figure 1

Nanoparticle preparation: Emulsion 1 (W/O) was obtained after an aqueous buffer containing Protamine Sulphate (PS) +/- DNA (blue) (solution I) was mixed with an organic buffer of PLGA with cationic lipids DOTAP (green) or DC-Chol (red) (solution II) and sonicated. Then another aqueous buffer containing PVA (solution III) was added to form Emulsion 2 (W/O/W). The mixture was briefly sonicated and NPs were formed by solvent evaporation. For DNA encapsulated NPs (in and both), pLuc DNA was added to solution I. For DNA adsorbed NPs (out or both), pLuc DNA was added to the NPs as described in the methods. The nanoparticles are designated as: green for PLGA/DOTAP, red for PLGA/DC-Chol and a blue plus inside the circle for encapsulated DNA. Blue on the outer circle designates adsorbed DNA.