Used in bioconjugation processes to link biomolecules such as proteins, peptides, or antibodies with high specificity. The aldehyde group reacts efficiently with aminooxy or hydrazide groups under mild conditions, forming stable oxime or hydrazone bonds. PEG3 spacer enhances solubility and reduces aggregation, making it suitable for applications in drug delivery, diagnostic assays, and surface immobilization. Biotin enables detection or purification using streptavidin-based systems, useful in ELISA, flow cytometry, and pull-down assays. Commonly applied in chemical biology and proteomics for labeling and capturing target molecules.