1,2-Distearoyl-sn-glycero-3-Phosphoethanolamine is the phospholipid, containing the saturated long-chain stearic acid inserted at the sn-1 and sn-2 positions, that used for the generation of micelles and liposomes. Polyethylene glycol (PEG)-modified 1,2-Distearoyl-sn-glycero-3-Phosphoethanolamine (DSPE–PEG), which forms sterically stabilized micelles, is widely used as a lipid-based nanocarrier for drug delivery PEG-DSPE block copolymers are biocompatible and amphiphilic polymers that can be utilized in the preparation of liposomes, polymeric nanoparticles, polymer hybrid nanoparticles, solid lipid nanoparticles, lipid-polymer hybrid nanoparticles, and microemulsions. Particularly, the terminal groups of PEG can be activated and linked to various targeting ligands, which can prolong the circulation time, improve the drug bioavailability, reduce undesirable side effects, and especially target specific cells, tissues, and even the intracellular localization in organelles.