DPPE-PEG1-azide (DPPE-PEG1-N3) is a PEG-modified lipid containing an azide group. DPPE-PEG1-azide can undergo a copper-catalyzed azide-alkyne cycloaddition reaction (CuAAc) with molecules containing an alkynyl group. It can also undergo ring strain-driven alkyne-azide cycloaddition (SPAAC) reactions with molecules containing DBCO or BCN groups[1].