Alkyne PEG is a class of PEG linkers containing a triple bond that is reactive toward azide group under mild conditions. Alkyne PEG is widely used in Click Chemistry bioconjugation, bio-labeling, chemical biology & antibody drug conjugate (ADC). There are several different functional groups containing alkyne, such as Propargyl, DBCO (Dibenzocyclooctyne) and BCN (bicyclo[6.1.0]nonyne). The PEG arm increases the hydrophilicity of these linkers.