To further assess the robustness of the prebuilt structures, we conducted self-assembly simulations using the same lipid compositions as in the pre-equilibrated structures. Within the first tens of nanoseconds, lipids assembled around the RNA duplexes. In all of the systems (including Lipid 2), lipids adopted an inverse hexagonal phase. As expected from an initial random distribution of lipids, DSPC was not present only on the LNP surface, but equally distributed in its interior (Figure ). Furthermore, LNPs were less hydrated (9-10 mass% of water inside LNP, Table ) and with a significant reduction of the amount of Cl -beads trapped within the core of LNP: 112 Cl -for Lipid 10, 49 Cl -for Lipid 2 and 128 Cl -for MC3.