Used as a key intermediate in the synthesis of PEGylated compounds, enhancing drug solubility and stability. Commonly employed in bioconjugation for attaching polyethylene glycol (PEG) chains to peptides, proteins, and nanoparticles, improving their pharmacokinetic profile. Also applied in the development of functionalized surfaces for biosensors and diagnostic devices due to its terminal carboxylic acid group and hydrophilic PEG-like spacer. Suitable for click chemistry applications when combined with appropriate coupling agents.