Used in bioconjugation and pharmaceutical formulation to link drugs, peptides, or targeting molecules with high solubility and reduced immunogenicity. The thiol group enables strong covalent bonding to gold surfaces or maleimide-functionalized compounds, making it ideal for biosensors and diagnostic devices. PEG12 spacer improves water solubility and extends circulation time in drug delivery systems. Commonly applied in PEGylation of proteins, surface modification of nanoparticles, and development of targeted therapeutics where controlled release and stability are critical. Also utilized in research for creating biocompatible coatings and functionalizing materials in biomedical engineering.