Used extensively in bioconjugation and drug delivery systems, it serves as a linker to attach therapeutic molecules or targeting ligands to nanoparticles or proteins. Its methanesulfonate group allows for efficient coupling reactions, while the PEG spacer enhances solubility and reduces immunogenicity. Commonly applied in the development of antibody-drug conjugates (ADCs) and prodrugs, it improves pharmacokinetics and bioavailability. Additionally, it is utilized in the modification of peptides and proteins to prolong their circulation time in vivo. Its versatility makes it valuable in creating innovative therapeutic agents and biomaterials.