Used as a hydrophilic linker in pharmaceutical and bioconjugation chemistry, enabling the attachment of drug molecules to targeting agents or fluorescent tags. Its polyether chain enhances water solubility and improves the pharmacokinetic profile of conjugated compounds. Commonly employed in the synthesis of PEG-like spacers for diagnostic probes, peptides, and antibody-drug conjugates. Also applied in surface modification of nanoparticles to reduce protein adsorption and prolong circulation time in vivo.