fig1

Figure 1. Ionizable lipids used in LNP formulations. Ionizable lipids used in clinical trials mostly contain head groups with pKa values below 7. Furthermore, the ratio between head group and tail group volume has been optimized to reach the optimal lipid per membrane area for sufficient endosomal escape. This resulted in different lipids with 2-4 alkyl tails with different degrees of saturation of the alkyl tails. LNP: Lipid nanoparticle.