Aminooxy-PEG3-methyl ester is widely used in bioconjugation and chemical biology for its ability to form stable oxime bonds with carbonyl-containing molecules. It is particularly valuable in the modification of proteins, peptides, and antibodies, enabling the attachment of functional groups, fluorescent dyes, or drug molecules for targeted delivery. This compound is also employed in the development of PEGylated therapeutics, enhancing the solubility, stability, and bioavailability of drugs. Additionally, it plays a role in surface functionalization of nanoparticles and biomaterials, facilitating their use in diagnostic imaging and drug delivery systems. Its versatility makes it a key reagent in the design of advanced biomolecular constructs for research and therapeutic applications.