m-PEG5-nitrile is widely used in bioconjugation and chemical synthesis due to its reactive nitrile group and polyethylene glycol (PEG) chain. The nitrile group allows for versatile modifications, making it valuable in creating functionalized molecules for drug delivery systems. Its PEG segment enhances solubility and biocompatibility, making it suitable for pharmaceutical applications, particularly in improving the pharmacokinetics of therapeutic agents. Additionally, it is employed in surface modification of nanoparticles and biomaterials to reduce immunogenicity and improve stability. In research, it serves as a linker or spacer in the development of probes and conjugates for biological studies.