Used extensively in bioconjugation, it facilitates the attachment of proteins, peptides, or other molecules to surfaces or other biomolecules. Its maleimide group reacts specifically with thiol groups (-SH), enabling stable bonds with cysteine residues in proteins. The sulfosuccinimide ester moiety reacts with primary amine groups (e.g., on lysine residues or other nucleophiles), while its sulfo group enhances water solubility, making it suitable for reactions in aqueous environments without the need for organic solvents. Commonly applied in antibody-drug conjugates, enzyme labeling, and the development of diagnostic assays, it ensures precise and efficient coupling. Additionally, it is utilized in the preparation of functionalized nanoparticles and biomaterials for targeted drug delivery and imaging applications.