Used in bioconjugation processes to link biomolecules such as peptides, proteins, or antibodies with high specificity. The aldehyde group (Ald) reacts efficiently with aminooxy or hydrazide groups, enabling stable oxime or hydrazone bond formation under mild conditions. The PEG11 spacer enhances solubility in aqueous and organic media, reduces aggregation, and minimizes non-specific binding, making it ideal for constructing antibody-drug conjugates (ADCs) and targeted therapeutics. The terminal primary amine (NH2) allows further modification with activated esters, isocyanates, or other amine-reactive linkers. Commonly applied in the development of diagnostic probes, imaging agents, and drug delivery systems where controlled spacing and multi-functionalization are critical.