Cy 5.5 Azadibenzocyclooctyne

The azadibenzocyclooctyne group contains a strained cyclooctyne ring that reacts with an azide through strain-promoted azide-alkyne cycloaddition without a copper catalyst. This reaction forms a stable triazole linkage between Cy5.5-DBCO and the azide-bearing target. The catalyst-free mechanism supports labeling in complex biochemical samples for subsequent fluorescent analysis.

Cy5.5 supplies the fluorescent readout after the click reaction attaches the reagent to an azide-bearing biomolecule. As a near-infrared dye, it allows the labeled target to be detected through fluorescence rather than inferred only from chemical attachment. This connects molecular tagging with visualization, molecular tracking, and analysis of biomolecular interactions in biochemical samples.

Labeling depends on the target presenting an azide group, because that group is the reaction partner for the strained cyclooctyne. Consequently, the reagent can be directed toward azide-bearing proteins, nucleic acids, glycans, and other biomolecular targets rather than serving as a universal label for every molecule. The azide therefore determines chemical compatibility.

A basic workflow begins with an azide-bearing biomolecule, followed by exposure to Cy5.5-DBCO so the two reactive groups can undergo copper-free cycloaddition. The resulting triazole-linked conjugate is then examined through the Cy5.5 fluorescence signal. This sequence converts selective chemical attachment into a detectable label for biochemical analysis.

It can be applied to proteins, nucleic acids, glycans, and other targets that carry an azide suitable for the cycloaddition. Once labeled, these biomolecules become accessible to fluorescence-based detection and tracking. In biochemistry, that capability supports experiments focused on monitoring molecular targets and analyzing their interactions within complex biological samples.

The copper-free format is useful when labeling is performed in complex samples, where the reagent can react with an azide-bearing biomolecule through its strained cyclooctyne group. Cy5.5 then provides a fluorescence-based means to detect the resulting conjugate. Together, chemical selectivity and optical readout support molecular tracking and interaction analysis.