Azido-PEG2-C2-sulfonic acid | CAS 1817735-39-9

Azido-PEG2-C2-sulfonic acid is a PEG-based azide click chemistry reagent designed for bioorthogonal conjugation workflows. As an azide-bearing linker, it is commonly used in strain-promoted or copper-catalyzed azide–alkyne cycloaddition strategies to attach functional payloads to biomolecules, surfaces, or polymeric materials. The short PEG spacer and terminal sulfonic acid functionality provide aqueous compatibility and handleable ionic character, making it useful for building water-soluble conjugates and imaging or assay reagents in chemical biology and materials research.

1. Water-Soluble Conjugation

Azido-PEG2-C2-sulfonic acid is frequently used to introduce a hydrophilic azide handle into proteins, peptides, and carbohydrate derivatives for downstream click conjugation. The PEG spacer supports efficient coupling in aqueous buffers, while the sulfonic acid group helps maintain solubility and reduces aggregation during labeling and purification. Researchers often select this reagent when they need a stable, water-compatible attachment point that can be carried through labeling, desalting, and analytical characterization prior to final functionalization.

2. Surface And Material Labeling

Azido-PEG2-C2-sulfonic acid is well suited for functionalizing polymer films, hydrogels, and other biomaterial surfaces that require ionic, water-wettable presentation of a reactive azide group. In materials science and chemical biology, azide-functionalized coatings are used as modular platforms for subsequent attachment of fluorescent tags, affinity ligands, or reactive biomolecule conjugates via click chemistry. The sulfonic acid functionality can also improve charge-assisted interactions with oppositely charged components during material assembly and post-modification steps.

3. Molecular Imaging Probe Building

Azido-PEG2-C2-sulfonic acid is commonly incorporated as a linker intermediate in the construction of fluorescent and luminescent imaging probes that rely on azide click handles for modular assembly. The PEG spacer supports conjugate flexibility and helps maintain probe solubility in labeling buffers, which is important for consistent probe performance during in vitro imaging workflows. By providing a chemically defined azide moiety with ionic character, this reagent supports scalable probe synthesis for assay development and imaging studies in research laboratories.

4. Diagnostic Reagent And Assay Platforms

Azido-PEG2-C2-sulfonic acid is used to create clickable assay components, including azide-functional capture reagents and labeling intermediates for multiplexing workflows. The sulfonic acid-containing PEG linker supports aqueous handling and can be advantageous when preparing conjugates that must remain soluble and stable through incubation, washing, and buffer-exchange steps. Many diagnostic reagent development teams use azide-functional linkers to standardize how probes, reporters, or affinity elements are attached, enabling rapid iteration of assay formats without re-optimizing the underlying conjugation chemistry each time.