Used as a hydrophilic linker in drug delivery systems, particularly in antibody-drug conjugates (ADCs) and peptide therapeutics. Its extended polyethylene glycol chain enhances solubility and improves pharmacokinetic properties by reducing aggregation and minimizing immune recognition. Commonly employed in bioconjugation to spacer molecules, allowing greater flexibility and accessibility between functional components. Also applied in surface modification of nanoparticles to increase biocompatibility and circulation time in vivo.