This chemical is widely used in bioconjugation and drug delivery systems due to its polyethylene glycol (PEG) chain, which enhances solubility and stability of biomolecules. The amine group (H2N-) allows for easy attachment to proteins, peptides, or other targeting molecules, while the t-butyl ester (COOtBu) provides a protective group that can be removed under specific conditions to expose a reactive carboxyl group. This makes it valuable in creating prodrugs or controlled-release formulations. Additionally, its long PEG spacer improves biocompatibility and reduces immunogenicity, making it suitable for therapeutic applications such as antibody-drug conjugates, nanoparticles, and targeted cancer therapies.