Used in bioconjugation to link proteins, peptides, or drugs through primary amine groups, forming stable amide bonds. Its four reactive arms allow for multi-directional crosslinking, making it ideal for creating hydrogels in tissue engineering and drug delivery systems. Commonly applied in pharmaceutical formulations to improve solubility, stability, and circulation time of therapeutic molecules. Also utilized in surface modification of nanoparticles and medical devices to reduce immunogenicity and enhance biocompatibility.