Cyanine5 phosphoramidite

Cyanine5 phosphoramidite is a cyanine dye phosphoramidite building block designed for incorporation into oligonucleotides via automated DNA/RNA synthesis. The cyanine scaffold provides strong fluorescence in the red spectral region, enabling sensitive optical readouts for labeled nucleic acids. As a reactive nucleoside analog format, it is commonly selected when researchers need a defined dye position for fluorescence imaging, hybridization assays, and molecular detection workflows.

1. Oligonucleotide Fluorescent Labeling

Cyanine5 phosphoramidite is used by molecular biology and chemical biology groups to introduce a red-emitting Cyanine5 fluorophore at a specific site within DNA or RNA strands. Researchers incorporate it during oligonucleotide synthesis to generate fluorescently labeled probes for hybridization studies, nucleic acid binding experiments, and fluorescence-based readouts where dye placement relative to the recognition sequence is critical. The phosphoramidite format supports routine solid-phase workflows and helps maintain consistent conjugate construction for downstream assays.

2. Fluorescence Hybridization Probes

Cyanine5 phosphoramidite is frequently employed to build fluorescence hybridization probes for nucleic acid detection formats that rely on target-dependent fluorescence changes. In typical workflows, labeled oligonucleotides are hybridized to complementary sequences and monitored by fluorescence microscopy, plate readers, or gel-based fluorescence analysis to visualize or quantify nucleic acid interactions. Because the dye is covalently attached through oligonucleotide synthesis, the resulting probe is well suited for experiments requiring stable fluorescent tagging of the nucleic acid reporter.

3. FRET Pair Oligonucleotides

Cyanine5 phosphoramidite is also used in FRET-based nucleic acid constructs where Cyanine5 serves as a donor or acceptor in proximity-dependent fluorescence experiments. Teams developing molecular beacons, hybridization sensors, or distance-reporting oligonucleotides position Cyanine5 within defined sequence contexts so that fluorescence transfer can be read out upon structural switching or target binding. This enables fluorescence monitoring of nucleic acid conformational changes and hybridization events using instrument-compatible red-channel detection.

4. Fluorescent Standards For Nucleic Acid Assays

Cyanine5 phosphoramidite supports assay development and method optimization by enabling preparation of well-defined fluorescent oligonucleotide standards. Researchers use Cyanine5-labeled sequences to calibrate fluorescence measurements, verify labeling consistency, and validate assay workflows such as probe hybridization performance in experimental pipelines. This use is especially common in labs that need reproducible red fluorescence signals from sequence-defined nucleic acid reporters for comparative studies and imaging optimization.