iFluor® IRDye 800RS is a near-infrared fluorescent dye engineered for nucleic acid labeling applications. It exhibits high water solubility but reduced salt tolerance compared to iFluor® IRDye 800 CW. The increased hydrophobicity of iFluor® IRDye 800RS enhances its performance in organic solvent-based reactions while maintaining sufficient aqueous solubility, making it particularly suitable for conjugation to thiol-modified oligonucleotides and nucleic acids.

The maleimide-functionalized derivative of iFluor® IRDye 800RS undergoes rapid and selective Michael addition with thiol groups under physiological conditions, enabling stable covalent attachment to thiol-modified DNA and RNA. This conjugation strategy is widely utilized in fluorescence-based hybridization assays, molecular imaging, and diagnostic applications. Following conjugation, labeled nucleic acids can be purified via reverse-phase chromatography, yielding high-purity conjugates with minimal residual unreacted dye.

The physicochemical properties of iFluor® IRDye 800RS provide a controlled balance between aqueous and organic solubility, optimizing its utility in diverse labeling strategies requiring near-infrared fluorescence. iFluor® IRDye 800RS, manufactured by AAT Bioquest, is structurally identical to IRDye 800RS (IRDye® is the trademark of LI-COR).