Used as a crosslinking agent in hydrogel formation for biomedical applications, particularly in drug delivery systems and tissue engineering. Its functional carboxy groups allow conjugation with bioactive molecules such as peptides or proteins, enabling targeted release and enhanced biocompatibility. The polyethylene glycol backbone provides hydrophilicity and flexibility, improving solubility and reducing immunogenicity. Commonly employed in designing responsive biomaterials due to its ability to form stable, biodegradable networks under physiological conditions.