Near Infrared (NIR) Fluorescent Dyes
Although most fluorophophores operate in visible or ultraviolet parts of the spectrum, near infrared (NIR) area is a very promising for fluorescence detection and imaging.
In infrared, much less background fluorescence is observed on microarrays, and tissue samples. This makes NIR dyes an ideal choice for the cases where low background, and high signal-to-noise ratio is critical.
Biological tissues possess "near infrared window" of transparency above 700 nm (actual value depends on tissue type). This allows for in-depth imaging of organisms in real-time, non-destructive fashion. Labeling of a biomolecule (peptide, protein, or other) with NIR dye makes it possible to track it, and study distribution of the molecule in organism. This type of imaging is a great tool for life science and drug design.
Lumiprobe offers two near infrared fluorophores: Cy7, and Cy7.5.
The dyes belong to the cyanine family of dyes. Both possess high extinction coefficients. The internal polymethyne chain contains a cyclohexane moiety to increase rigidity and quantum yield. Fluorescence quantum yield is thus improved by 20% compared to the parent structures.
Cy7 | Cy7.5 | |
---|---|---|
Excitation wavelength | 750 nm | 788 nm |
Extinction at λmaxex | 199,000 | 223,000 |
Emission wavelength | 773 nm | 808 nm |
Stokes shift | 23 nm | 20 nm |
Availability |
NHS ester (amine-reactive) NHS ester, water soluble (amine-reactive) Maleimide (thiol-reactive) Maleimide, water soluble (thiol-reactive) Hydrazide (carbonyl-reactive) Primary amine Primary amine, water soluble Carboxylic acid Carboxylic acid, water soluble Azide (for Click chemistry) Azide, water soluble (for Click chemistry) Alkyne (for Click chemistry) Alkyne, water soluble (for Click chemistry) Tetrazine (for Click chemistry) DBCO (for Click chemistry) |
NHS ester (amine-reactive) NHS ester, water soluble (amine-reactive) Maleimide (thiol-reactive) Hydrazide (carbonyl-reactive) Primary amine Carboxylic acid Carboxylic acid, water soluble Azide (for Click chemistry) Azide, water soluble (for Click chemistry) Alkyne (for Click chemistry) Alkyne, water soluble (for Click chemistry) Tetrazine (for Click chemistry) |
Succinimide esters are most useful for the labeling of amino groups in various biomolecules, such as proteins and peptides. Azides and alkynes are reactive dyes for advanced and efficient Click Chemistry reaction. We also recommend preparing NIR dye labeled oligonucleotides through post-synthetic Click Chemistry labeling of alkynylated oligos with dye azides.
