Used primarily as a cyanine dye in biological staining and fluorescence labeling. Commonly applied in microscopy and flow cytometry for detecting cellular components due to its strong absorption and emission in the near-infrared range. Exhibits good solubility in aqueous solutions, making it suitable for live-cell imaging with minimal toxicity. Also employed in diagnostic assays and DNA detection methods where high sensitivity and low background interference are required. Its sulfonate groups enhance water solubility and reduce nonspecific binding.