m-PEG3-NHS ester is widely used in bioconjugation and chemical modification processes. It is particularly valuable in attaching polyethylene glycol (PEG) chains to proteins, peptides, or other biomolecules, enhancing their solubility, stability, and biocompatibility. This compound is commonly applied in drug delivery systems to improve the pharmacokinetics and reduce immunogenicity of therapeutic agents. It also plays a role in surface modification of nanoparticles, enabling targeted delivery and prolonged circulation in the body. Additionally, it is utilized in research for labeling biomolecules in studies involving imaging, diagnostics, and biomolecular interactions.