m-PEG5-Tos is widely used in bioconjugation and chemical synthesis as a versatile reagent for modifying biomolecules. Its tosyl group allows for efficient attachment to nucleophiles like amines or thiols, making it valuable for creating PEGylated compounds. This modification enhances solubility, stability, and biocompatibility of proteins, peptides, and other biomolecules, which is particularly useful in drug delivery systems and therapeutic applications. Additionally, it serves as a linker in the development of prodrugs and targeted therapies, improving pharmacokinetics and reducing immunogenicity. Its role in surface functionalization of nanoparticles and materials further extends its utility in biomedical research and diagnostics.