N-(Amino-PEG5)-N-bis(PEG4-acid) is widely used in bioconjugation and drug delivery systems due to its polyethylene glycol (PEG) chains, which enhance solubility, stability, and biocompatibility. It serves as a versatile linker for attaching bioactive molecules, such as peptides, proteins, or drugs, to nanoparticles or other carriers. The amino group allows for covalent bonding with carboxyl or other reactive groups, while the PEG chains minimize immunogenicity and prolong circulation time in the body. This compound is particularly valuable in developing targeted therapies, where precise delivery of therapeutic agents to specific cells or tissues is required. Additionally, it is employed in the design of hydrogels and biomaterials for tissue engineering, where its properties support controlled release and improved biocompatibility.