M-PEG3-S-Acetyl is widely used in bioconjugation and drug delivery systems. Its polyethylene glycol (PEG) linker enhances solubility and stability of compounds, making it valuable in modifying proteins, peptides, and small molecules. It is particularly useful in creating antibody-drug conjugates (ADCs) by linking cytotoxic drugs to antibodies, improving targeted delivery to cancer cells. The thiol-reactive acetyl group allows for specific conjugation to cysteine residues, enabling precise modifications. Additionally, it is employed in surface functionalization of nanoparticles and biomaterials, enhancing biocompatibility and reducing immunogenicity. Its applications also extend to diagnostic imaging, where it is used to modify contrast agents for better performance in vivo.