Used as a crosslinking agent in hydrogel formation for biomedical applications, particularly in drug delivery systems and tissue engineering. Its functional carboxy groups allow covalent attachment to proteins or peptides, enabling the development of biocompatible conjugates with controlled release properties. Also employed in modifying surfaces of medical devices to improve biocompatibility and reduce protein fouling. The polyethylene glycol backbone provides water solubility and enhances stability in physiological environments.