mPEG12-Mal is widely used in bioconjugation and drug delivery systems due to its ability to modify and stabilize biomolecules. Its maleimide group allows for selective and efficient conjugation with thiol-containing compounds, such as cysteine residues in proteins or peptides, under mild conditions. This property makes it valuable in the development of antibody-drug conjugates (ADCs), where it enhances solubility, prolongs circulation time, and reduces immunogenicity. Additionally, it is employed in surface modification of nanoparticles and liposomes to improve their biocompatibility and targeting efficiency. In research, mPEG12-Mal is utilized to label and track biomolecules in cellular and molecular studies, aiding in the understanding of biological processes. Its applications also extend to the creation of hydrogels and biomaterials for tissue engineering and regenerative medicine.