Aminooxy-PEG4-alcohol is widely used in bioconjugation and chemical biology due to its unique reactivity with carbonyl groups, such as aldehydes and ketones. It is commonly employed in the modification of proteins, peptides, and other biomolecules, enabling the attachment of functional groups or labels for research and therapeutic purposes. This compound is particularly useful in the development of antibody-drug conjugates (ADCs), where it facilitates the precise linking of cytotoxic drugs to antibodies, enhancing targeted cancer therapies. Additionally, it is utilized in the synthesis of PEGylated compounds, improving the solubility, stability, and bioavailability of drugs. Its application also extends to surface functionalization in materials science, where it aids in creating bioactive surfaces for biosensors and diagnostic tools.