Azide-PEG1-Desthiobiotin is a PEG derivative comprising desthiobiotin, a single PEG unit, and an azide group (azide). Biotin within this compound can form a stable non-covalent bond with streptavidin (Streptavidin). The azide group facilitates copper-catalyzed azide-alkyne cycloaddition reactions (CuAAc) with molecules containing alkyne groups. Additionally, it can undergo strain-promoted azide-alkyne cycloaddition reactions (SPAAC) with molecules that have DBCO or BCN groups.