Bromo-PEG2-acetic acid is widely used in bioconjugation and pharmaceutical research due to its bifunctional structure. The bromo group serves as a reactive handle for nucleophilic substitution, enabling efficient coupling with amines or thiols in biomolecules. The PEG2 (diethylene glycol) spacer improves solubility in aqueous and organic solvents, reduces aggregation, and enhances the flexibility of the linked molecules. This makes it valuable in the synthesis of antibody-drug conjugates (ADCs), peptide modifications, and targeted therapeutics.

The terminal acetic acid group allows for further activation and conjugation, typically via EDC/NHS chemistry, to amines on proteins or other substrates. Its moderate linker length balances stability and reactivity, making it ideal for constructing cleavable or non-cleavable linkers in drug delivery systems. Additionally, it is used in the development of PEGylated compounds to improve pharmacokinetic properties such as circulation time and bioavailability.

In diagnostic applications, Bromo-PEG2-acetic acid is employed to introduce spacer arms between detection moieties (e.g., fluorophores, biotin) and targeting molecules, minimizing steric interference and enhancing binding efficiency.