1,1,1-Trifluoroethyl-PEG4-aminooxy is primarily utilized in bioconjugation and chemical biology for the modification of biomolecules. Its aminooxy group enables selective reactions with carbonyl-containing compounds, such as aldehydes and ketones, making it valuable for labeling proteins, peptides, and other biomolecules. This chemical is often employed in the development of antibody-drug conjugates (ADCs), where it facilitates the attachment of therapeutic payloads to antibodies, enhancing targeted drug delivery. Additionally, it is used in the synthesis of PEGylated compounds, improving solubility, stability, and pharmacokinetics of drugs. Its trifluoroethyl group can also provide metabolic stability, making it useful in the design of probes and imaging agents for biomedical research.