Used in bioconjugation to attach polyethylene glycol (PEG) chains to proteins, peptides, or nanoparticles, improving solubility and stability while reducing immunogenicity. Commonly applied in drug delivery systems to extend circulation time of therapeutic agents. Enables surface modification of gold nanoparticles and biosensors due to strong thiol-gold interaction. Facilitates the development of PEGylated liposomes and hydrogels for controlled release and biomedical applications. Also used in creating non-fouling surfaces in diagnostic devices and implants.