Used in bioconjugation and bioorthogonal chemistry for labeling and detecting biomolecules. The azide group reacts selectively with alkynes via copper-catalyzed or strain-promoted click chemistry, enabling efficient attachment to proteins, antibodies, or nucleic acids. PEG3 spacer enhances solubility and reduces steric hindrance, improving reaction efficiency and target accessibility. Biotin moiety allows strong binding to streptavidin or avidin systems, facilitating detection, purification, or immobilization in assays such as ELISA, flow cytometry, and microscopy. Commonly applied in proteomics, live-cell imaging, and targeted drug delivery research.