Figure 1.
Size (black squares) and zeta-potential (grey triangles) of grapholipoplexes as a function of the DNA/ graphene oxide nanoflakes with cationic lipids (GOCL) weight ratio, RW. Grapholipoplexes exhibit typical charge inversion and “re-entrant condensation”. At the iso-electric point (RW = 0.3), grapholipoplexes are neutrally charged and large in size (~800 nm). This is due to short-range van der Waals attraction that prevails over electrostatic repulsion between positively charged GOCL nanoparticles (NPs) and negatively charged DNA. On both sides of the evolution profile, grapholipoplexes are small-sized (~200 nm), with surface charge dominated by excess DNA (RW > 0.3) or excess cationic lipid (RW < 0.3).