Used in bioconjugation for labeling biomolecules such as proteins, peptides, and antibodies in aqueous solutions. The DBCO group reacts rapidly and selectively with azide-functionalized molecules via copper-free click chemistry, making it ideal for live-cell labeling and in vivo applications where copper toxicity is a concern. The sulfo-NHS ester group enables efficient coupling to primary amines (e.g., lysine residues) under mild conditions, forming stable amide bonds. Commonly applied in the development of antibody-drug conjugates, fluorescent probes, and functionalized nanoparticles. Water solubility from the sulfo group eliminates the need for organic solvents, improving biocompatibility and simplifying reaction setup.