Used in bioconjugation for labeling and modifying biomolecules such as proteins, peptides, nucleic acids, and glycoproteins. Enables copper-free click chemistry via the DBCO group, which reacts specifically and rapidly with azide-functionalized molecules, making it ideal for sensitive biological systems where copper catalysts are toxic or disruptive. The oxyamine group allows direct conjugation to carbonyl-containing functionalities, such as aldehydes or ketones on oxidized proteins or glycans. Commonly applied in live cell imaging, drug delivery systems, development of antibody-drug conjugates, and vaccine design. The PEG3 spacer improves water solubility, reduces steric hindrance, and minimizes non-specific protein aggregation, enhancing reaction efficiency. Frequently employed in surface functionalization of nanoparticles and biosensors for improved biocompatibility and target specificity.