Used in bioconjugation and drug delivery systems, Ald-Ph-PEG6-acid serves as a heterobifunctional linker molecule featuring an aldehyde group on a phenyl moiety and a terminal carboxylic acid connected by a PEG6 (polyethylene glycol) chain, which enhances solubility and stability. Commonly applied in the development of antibody-drug conjugates (ADCs) and targeted therapies, it facilitates the attachment of drugs or imaging agents to biomolecules like proteins or peptides. The aldehyde group allows for specific reactions with primary amines (e.g., forming Schiff bases), while the carboxylic acid can be activated (e.g., to NHS ester) for amide bond formation. Additionally, it is utilized in surface modification of nanoparticles to improve biocompatibility and reduce immunogenicity.