Biotin PEG hydrazide (Biotin-PEG-NHNH2) is a heterobifunctional polyethylene glycol derivative. Biotinylated PEG can be used to bind to avidin or streptavidin. Biotin can be easily detected by biotin/streptavidin binding assay and is widely used for molecule target detection. Hydrazide, on the other hand, can be used to react with carbohydrate.