DODAP (C18:1 DAP) is an ionizable cationic lipid used in the liposomal transfection of nucleic acid therapeutics into cells. At physiological pH, it is neutral in charge, allowing for favourable interactions with cellular membranes. In acidic microenvironments, e.g. inside endosomes, it is protonated to produce a positive charge, leading to the release of its RNA or DNA drug agents.