PEG3-O-CH2COOH is widely used in bioconjugation and drug delivery systems due to its ability to improve solubility and stability of therapeutic compounds. It serves as a linker molecule in the development of antibody-drug conjugates (ADCs), enabling the attachment of drugs to antibodies for targeted cancer therapy. Additionally, it is employed in the modification of peptides and proteins to enhance their pharmacokinetic properties, such as prolonging circulation time in the body. Its hydrophilic PEG moiety reduces immunogenicity and prevents aggregation, making it valuable in the formulation of biologics. Furthermore, it is utilized in the synthesis of hydrogels and biomaterials for tissue engineering applications, providing controlled release of bioactive molecules.