Aminooxy-PEG3-bromide is widely used in bioconjugation and chemical biology for linking molecules through oxime bond formation. Its aminooxy group reacts selectively with aldehydes or ketones, making it valuable for modifying proteins, peptides, or other biomolecules. The PEG3 spacer enhances solubility and reduces steric hindrance, improving reaction efficiency. This compound is particularly useful in antibody-drug conjugates (ADCs), where it facilitates the attachment of cytotoxic drugs to antibodies for targeted cancer therapy. Additionally, it is employed in surface functionalization of nanoparticles or polymers for drug delivery systems, enabling precise control over payload release. Its application also extends to the development of biosensors and diagnostic tools, where it helps immobilize biomolecules onto surfaces for accurate detection.