sulfo-Cyanine5.5 tetrazine

Sulfo-Cyanine5.5 tetrazine is a water-soluble tetrazine-functionalized cyanine dye designed for inverse-electron-demand Diels-Alder click chemistry with trans-cyclooctene (TCO)-bearing partners. In fluorescence labeling workflows, the cyanine scaffold provides far-red emission for sensitive visualization, while the tetrazine handle enables rapid, bioorthogonal conjugation to TCO-tagged biomolecules, polymers, and surfaces for microscopy and imaging reagent development.

1. TCO Bioconjugation Labeling

Sulfo-Cyanine5.5 tetrazine is used to fluorescently label TCO-modified antibodies, affibodies, peptides, and other targeting ligands in chemical biology and biomarker research. Researchers typically prepare TCO-functionalized biomolecules first, then perform the tetrazine-mediated click step to install the far-red cyanine dye under conditions compatible with sensitive biomolecular constructs. This approach is valued for constructing defined dye-to-biomolecule conjugates for imaging experiments, including localization studies in complex biological samples and multistep probe assembly where orthogonality and timing matter.

2. Fluorescence Microscopy Imaging

Sulfo-Cyanine5.5 tetrazine supports far-red fluorescence microscopy applications where strong background suppression and clear cellular or subcellular contrast are required. Imaging teams use it to generate fluorescent conjugates for tracking biomolecule binding, uptake, or distribution after conjugation to TCO-tagged carriers such as cell-surface targeting reagents, extracellular matrix binders, or nanoparticle platforms. The sulfonated dye improves aqueous handling for staining and labeling workflows, enabling straightforward preparation of imaging reagents for confocal and widefield fluorescence microscopy.

3. Flow Cytometry Dye Conjugates

Sulfo-Cyanine5.5 tetrazine is applied in flow cytometry workflows that require a far-red fluorescent channel for labeling TCO-bearing reagents. Common use cases include preparing fluorescent antibody conjugates or labeling reagent panels for cell-surface marker analysis, where the tetrazine click step is used to attach the cyanine dye to TCO-tagged targeting molecules immediately prior to experiments. This enables consistent reagent preparation for instrument-based quantification of labeled populations while leveraging the dye's far-red spectral position to reduce overlap with common fluorophores.

4. Nanoparticle And Surface Functionalization

Sulfo-Cyanine5.5 tetrazine is used to functionalize TCO-modified nanoparticles and biomaterial surfaces with a fluorescent reporting dye for materials characterization and molecular imaging reagent development. Materials scientists and imaging teams incorporate the dye into coatings, polymer layers, and surface-engineered platforms by reacting with TCO-functionalized surfaces or colloids, producing fluorescently traceable constructs for adsorption studies, trafficking experiments, and platform-to-platform comparisons. The water solubility of the sulfonated cyanine supports labeling in aqueous processing conditions used for biomaterials and colloidal systems.