Used in surface functionalization of gold nanoparticles due to the thiol group, enabling stable self-assembled monolayers. The polyether chain provides excellent water solubility and resistance to nonspecific protein adsorption, making it ideal for biomedical applications such as biosensors, targeted drug delivery, and diagnostic imaging. Frequently employed in bioconjugation strategies where the carboxylic acid end is activated to couple with biomolecules like antibodies, peptides, or fluorescent labels. Its flexible spacer arm enhances binding accessibility in immunoassays and molecular recognition systems.