DSPE-PEG4-acid is a PEG derivative containing DSPE and carboxylic acid moieties. 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 carboxylic acid group can react with primary amines using activators such as EDC and DCC to form stable amide bonds.