DSPE-PEG5-azide is a heterobifunctional PEG linker. The DSPE-PEGs have been FDA approved for medical applications. The hydrophobic properties of the DSPE allow for the encapsulation and congregation of other hydrophobic drugs. The hydrophilic PEG linker increases the water solubility of the overall compound allowing for the delivery of the drug. The azide group can undergo copper-catalyzed Click Chemistry reactions with alkynes, DBCO and BCN.