m-PEG8-CH2COOH is widely used in bioconjugation and drug delivery systems due to its hydrophilic polyethylene glycol (PEG) chain and reactive carboxyl group. The PEG moiety enhances solubility, stability, and biocompatibility of conjugated molecules, making it ideal for modifying proteins, peptides, and nanoparticles. The terminal carboxyl group allows for covalent attachment to amines or other functional groups, facilitating the creation of targeted drug delivery systems or diagnostic agents. It is also employed in surface modification to reduce immunogenicity and improve the pharmacokinetics of therapeutic compounds. Additionally, it finds applications in creating hydrogels and biomaterials for tissue engineering and regenerative medicine.