Used in bioconjugation processes, particularly in click chemistry reactions, to label and attach biomolecules such as proteins, antibodies, or nucleic acids. The azide group reacts efficiently with alkyne-functionalized compounds via copper-catalyzed azide-alkyne cycloaddition (CuAAC), enabling site-specific modification. The PEG23 spacer enhances solubility, reduces non-specific binding, and increases the flexibility and accessibility of the biotin tag, improving detection sensitivity in assays like ELISA, flow cytometry, and immunohistochemistry. Also employed in pull-down assays and target immobilization on streptavidin-coated surfaces for protein purification or diagnostic applications.