PEG derivatized lipids are used to increase the circulation time of liposomes and lipid nanoparticles (LNPs) in vivo. The hydrophilic PEG chains decrease interactions with the reticular-endothelial system and increases the size of the particles both of which result in lowered clearance rate from the body. The alkyne group can be derivatized with an azide-containing molecule via a Cu-catalyzed “click” reaction.
