This chemical is widely used in bioconjugation and click chemistry applications. Its structure, featuring multiple PEG (polyethylene glycol) spacers and azide groups, makes it highly effective for linking biomolecules, such as proteins, peptides, or antibodies, to other entities like dyes, drugs, or solid supports. The NHS ester group allows for efficient coupling with primary amines, while the azide groups enable copper-catalyzed azide-alkyne cycloaddition (CuAAC), a popular click chemistry reaction. This dual functionality is particularly useful in drug delivery systems, where it helps create stable and biocompatible conjugates. Additionally, it is employed in surface modification, where it can functionalize materials for biosensing or tissue engineering purposes. The PEG spacers enhance solubility and reduce immunogenicity, making it suitable for in vivo applications.