Sulfo-Cyanine3 carboxylic acid

Sulfo-Cyanine3 carboxylic acid is a sulfonated cyanine fluorophore designed for aqueous fluorescent labeling workflows, offering strong optical performance in the visible-red region and a carboxylic acid handle for conjugation strategies. Its charged sulfonate group supports water compatibility, making it a common building block for preparing fluorescent conjugates used in microscopy, labeling assays, and fluorescence-based analytical development.

1. Fluorescent Protein Labeling

Sulfo-Cyanine3 carboxylic acid is frequently used to generate red-emitting fluorescent protein conjugates for imaging and quantitative fluorescence assays. Researchers typically incorporate it into labeling workflows where a reactive carboxyl group is used to attach the dye to proteins or protein-containing reagents, enabling visualization of labeled targets in cell biology experiments and supporting downstream readouts such as fluorescence microscopy and plate-based fluorescence measurements. Because the dye is sulfonated, conjugates prepared from it are often chosen when aqueous handling and consistent staining conditions are important for routine lab protocols.

2. Fluorescence Microscopy Tracing

Sulfo-Cyanine3 carboxylic acid serves as a practical fluorophore for cellular and biomolecular tracing experiments in fluorescence microscopy, particularly when a bright, red-channel signal is desired for multi-color imaging layouts. After incorporation into appropriate labeling conjugates, the dye enables localization studies of labeled biomolecules on fixed samples and in imaging workflows where wash stability and water-compatible staining reagents are required. Imaging labs and microscopy method developers commonly select cyanine-based dyes like this when they need a robust fluorescent label that integrates into standard staining and imaging pipelines.

3. Oligonucleotide and Probe Labeling

Sulfo-Cyanine3 carboxylic acid is also used to produce fluorescent oligonucleotide labeling reagents and nucleic-acid-associated probes for fluorescence-based detection workflows. In these applications, the dye is incorporated to create labeled DNA or RNA constructs used for hybridization readouts, nucleic acid tracking experiments, and fluorescence monitoring in molecular biology assays. The sulfonated cyanine scaffold helps support aqueous conjugate preparation and consistent fluorescence labeling for nucleic acid workflows where the fluorophore must remain compatible with buffer conditions used during probe handling and measurement.

4. Flow Cytometry Conjugate Development

Sulfo-Cyanine3 carboxylic acid is employed in the development of flow cytometry-compatible fluorescent conjugates, where red-emitting signals are used to quantify labeled biomolecules in heterogeneous mixtures. Conjugate developers use the dye to construct antibody, affinity reagent, or other binding-partner labels that generate a measurable fluorescence shift during cytometric analysis. This fluorophore is commonly selected when a sulfonated cyanine dye is preferred for aqueous conjugation and when a visible-red emission channel aligns with existing instrument laser and filter configurations used in routine cytometry panels.