Bromo-PEG3-ethyl phosphonate is widely used in bioconjugation and chemical biology. It serves as a versatile linker for attaching biomolecules, such as proteins, peptides, or antibodies, to other functional groups or surfaces. Its phosphonate group allows for stable binding to metal oxides or surfaces, making it valuable in material science for creating functionalized coatings or nanoparticles. In drug delivery systems, it aids in the development of targeted therapies by enabling precise attachment of therapeutic agents to carriers. Additionally, it is employed in the synthesis of prodrugs or bioconjugates, enhancing solubility and bioavailability of active compounds. Its PEG spacer provides flexibility and reduces immunogenicity, making it suitable for in vivo applications.