Azido-PEG2-PFP ester is a PEG derivative with azide and PFP ester moieties. The azide can participate in copper-catalyzed Click Chemistry reactions with alkynes, DBCO and BCN to produce triazole linkages. The PFP is an amine reactive, activated ester. PFP esters form stable amide bonds and are less likely to undergo hydrolysis compared to other amine reactive moieties. The hydrophilic PEG linker increases the water solubility of compounds in aqueous environments.