Used in bioconjugation processes to link molecules with high specificity, particularly in pharmaceutical and biotechnology applications. Its thiol group reacts selectively with maleimides or gold surfaces, enabling the attachment of peptides, proteins, or nanoparticles. The PEG3 spacer enhances solubility and reduces aggregation, while the acetic acid terminus allows further coupling to amines via EDC/NHS chemistry. Commonly applied in the development of antibody-drug conjugates (ADCs), diagnostic probes, and surface functionalization of biosensors. Also utilized in creating hydrogels and multifunctional linkers where controlled spacing and reactivity are required.