NH2-PEG-NH2 is widely used in bioconjugation and drug delivery systems due to its bifunctional nature. It serves as a linker to attach bioactive molecules, such as proteins, peptides, or drugs, to nanoparticles or other surfaces, enhancing solubility and stability. In tissue engineering, it is utilized to modify scaffolds, promoting cell adhesion and growth. Additionally, it plays a role in surface modification of biomaterials to reduce immunogenicity and improve biocompatibility. Its applications also extend to the development of hydrogels for controlled drug release and in diagnostic assays for labeling and detection purposes.