Sulfo-Cyanine7.5 carboxylic acid

Sulfo-Cyanine7.5 carboxylic acid is a sulfonated, water-compatible cyanine dye designed for fluorescent labeling and imaging workflows where aqueous handling and strong near-infrared emission are beneficial. Its carboxylic acid functionality enables conjugation to amine-containing biomolecules and labeling platforms used in fluorescence microscopy, optical imaging, and fluorescence-based assay development. The dye's NIR spectral region supports reduced background from biological autofluorescence in many imaging setups.

1. Biomolecule Fluorescent Labeling

Sulfo-Cyanine7.5 carboxylic acid is used to prepare fluorescent conjugates for labeling proteins, peptides, and other amine-bearing biomolecules for downstream imaging and quantitative fluorescence assays. Researchers incorporate the dye into antibody conjugates, affinity reagents, and tracer molecules to visualize binding and distribution in aqueous buffers while leveraging the dye's near-infrared emission to improve signal contrast against autofluorescence. In chemical biology and biomolecular interaction studies, the carboxylate handle is a practical entry point for building stable dye conjugates that can be tracked by fluorescence readouts in plate-based assays or optical imaging instruments.

2. Fluorescence Microscopy Imaging

Sulfo-Cyanine7.5 carboxylic acid supports fluorescence microscopy applications that benefit from near-infrared detection, including cellular imaging of labeled targets and imaging of fluorescently tagged biomolecules in fixed or prepared samples. Its sulfonated structure helps maintain water solubility for staining and labeling workflows, while the dye's emission characteristics align well with common NIR-capable microscope configurations and filter sets used for multicolor experiments. Imaging groups use the dye to track labeled structures, monitor spatial localization of conjugates, and generate fluorescence maps for qualitative and semi-quantitative analysis.

3. Flow Cytometry Fluorescent Tracing

Sulfo-Cyanine7.5 carboxylic acid is applied in flow cytometry workflows that require a near-infrared fluorophore for labeling biomolecules on cells or for tracing labeled reagents in suspension assays. Laboratories use dye-conjugated antibodies or other affinity constructs to quantify fluorescence associated with specific binding events using NIR detection channels where available. The sulfonated dye format is particularly useful for preparing aqueous staining reagents and maintaining consistent labeling conditions across samples, enabling fluorescence-based gating and population analysis in research cytometry studies.

4. Fluorescence-Based Bioassay Development

Sulfo-Cyanine7.5 carboxylic acid is frequently used to build fluorescent assay reagents for monitoring binding, uptake, or reporter signal in plate-based formats. Assay developers conjugate the dye to recognition elements or reporter scaffolds to generate NIR fluorescence readouts compatible with standard fluorescence plate readers and imaging systems equipped for near-infrared detection. In screening and method development, the dye's water compatibility and carboxyl-functional labeling handle support practical reagent preparation for time-course measurements, endpoint assays, and fluorescence tracing of labeled components in complex assay matrices.