Used as a hydrophilic spacer or linker in pharmaceutical and polymer chemistry, enhancing solubility and flexibility in molecular design. Commonly employed in the synthesis of prodrugs, dendrimers, and functionalized nanoparticles where biocompatibility and chain mobility are required. Its repeating tetraethylene glycol units provide resistance to protein adsorption, making it useful in stealth coatings and diagnostic probes. Also applied in surface modification of biosensors and microarrays to reduce nonspecific binding and improve signal clarity.