Used in bioconjugation processes to link proteins, peptides, or other biomolecules to polyethylene glycol (PEG), enhancing solubility, stability, and circulation time of therapeutic agents. Commonly applied in the development of PEGylated drugs to reduce immunogenicity and improve pharmacokinetics. Also utilized in immobilizing biomolecules on surfaces for diagnostic assays and biosensors due to its reactive NHS ester group that readily binds primary amines. Suitable for creating hydrogels and functionalized polymers in drug delivery systems and tissue engineering.