Mal-PEG5-NHS ester is widely used in bioconjugation and chemical modification processes. It serves as a linker molecule to attach proteins, peptides, or other biomolecules to surfaces or other molecules, enabling the study of molecular interactions and cellular processes. This compound is particularly valuable in antibody-drug conjugate (ADC) development, where it helps link cytotoxic drugs to antibodies for targeted cancer therapy. Additionally, it is employed in surface functionalization for biosensors and nanomaterials, enhancing their biocompatibility and targeting capabilities. Its NHS ester group facilitates efficient coupling with primary amines, making it a versatile tool in biochemical research and therapeutic applications.