3-Azidopropionic Acid Sulfo-NHS ester | CAS 2055198-09-7

3-Azidopropionic Acid Sulfo-NHS ester is a sulfonate-containing, water-compatible NHS ester designed for rapid amide coupling to primary amines on biomolecules and biomaterial surfaces, followed by introduction of an azide handle for downstream click chemistry. As a bifunctional reagent, it combines an amine-reactive NHS ester with a terminal azide in a short propionic linker, enabling modular bioconjugation workflows for labeling, surface functionalization, and probe assembly. This reagent is widely used in chemical biology and molecular imaging research where orthogonal azide-based click reactions are preferred for attaching dyes, affinity tags, or imaging/assay components under mild aqueous conditions.

1. Protein Surface Labeling

3-Azidopropionic Acid Sulfo-NHS ester is commonly used to functionalize proteins and protein complexes that contain accessible lysine residues or engineered primary amines. The sulfo-NHS ester enables efficient coupling into aqueous buffers used in labeling pipelines, while the introduced azide provides a stable, bioorthogonal handle for subsequent strain-promoted or copper-catalyzed azide–alkyne cycloaddition. Researchers use this approach to prepare azide-functional protein conjugates for fluorescence microscopy, flow cytometry reagents, and assay-compatible detection constructs, where controlled incorporation of an azide tag is required without interfering with other reactive groups.

2. Antibody and Affinity Conjugates

3-Azidopropionic Acid Sulfo-NHS ester supports azide installation on antibodies, antibody fragments, and affinity reagents used in targeted binding assays and multiplexed detection formats. By converting lysine-rich regions into azide-bearing conjugates, the reagent allows flexible post-conjugation attachment of secondary reporters such as fluorophores, enzyme substrates, or polymeric tags through click chemistry. This modular strategy is especially valuable when researchers need to standardize labeling chemistry across different antibody lots or when they want to decouple the initial amine coupling step from the final attachment of the desired imaging or detection moiety.

3. Biomaterial and Surface Functionalization

3-Azidopropionic Acid Sulfo-NHS ester is frequently applied to introduce azide functionality onto biomaterial surfaces, including hydrogel matrices, polymer coatings, and membrane-like substrates that present primary amines. The sulfonate group improves water compatibility, making it practical for surface derivatization under conditions compatible with sensitive materials and complex labile components. Azide-functionalized materials produced using this reagent can then be patterned or uniformly decorated with clickable linkers, peptides, or imaging probes, enabling construction of functional interfaces for biosensing platforms, materials-based assays, and extracellular-matrix-mimetic research tools.

4. Molecular Imaging Probe Assembly

3-Azidopropionic Acid Sulfo-NHS ester is used in molecular imaging and diagnostic-reagent development workflows to generate azide-bearing targeting or carrier components that can be clicked to imaging reporters. The NHS ester chemistry provides a convenient route to install azides onto amine-containing scaffolds such as proteins, peptides, or other conjugatable carriers, while the terminal azide enables orthogonal attachment of imaging moieties in a later step. This separation of steps helps teams optimize labeling conditions for each component independently, supporting scalable probe assembly for fluorescence-based imaging reagents, radiochemistry-compatible precursor preparation, and multi-modal labeling strategies used in research laboratories.