NH2-PEG-COOH is widely used in bioconjugation and drug delivery systems due to its amphiphilic nature and biocompatibility. It serves as a linker molecule, connecting therapeutic agents like drugs or proteins to targeting molecules, enhancing solubility and stability. In nanotechnology, it is employed to modify nanoparticles, improving their dispersion and reducing immune recognition. It is also utilized in tissue engineering to functionalize surfaces, promoting cell adhesion and growth. Additionally, it plays a role in diagnostic applications, where it helps in attaching imaging agents to biomolecules for targeted detection. Its versatility makes it a valuable tool in biomedical research and therapeutic development.