m-PEG1-NHS ester is widely used in bioconjugation processes to modify proteins, peptides, and other biomolecules. It acts as a linker to attach polyethylene glycol (PEG) chains to target molecules, enhancing their solubility, stability, and bioavailability. This modification is particularly valuable in drug delivery systems, where PEGylation reduces immunogenicity and prolongs the circulation time of therapeutic agents in the body. Additionally, it is employed in surface functionalization of nanoparticles and biomaterials to improve their biocompatibility and performance in biomedical applications. The NHS ester group enables efficient and selective coupling with primary amines, making it a versatile tool in bioconjugation chemistry.