Used extensively in liposome and lipid nanoparticle formulations, particularly in drug delivery systems such as mRNA vaccines and cancer therapeutics. Its negatively charged head group helps stabilize lipid bilayers and influences membrane fluidity and fusion properties. Commonly employed in studies of membrane dynamics, apoptosis, and cell signaling due to its role as a mimic of natural anionic phospholipids found in cell membranes. Also utilized in in vitro models to investigate protein-lipid interactions and enzyme activity involving phospholipids.