Cy5.5 Maleimide

Unit Size
Price (USD)
1 mg
In stock
5 mg
In stock
25 mg
In stock
100 mg
In stock

    Cy5.5 dyes are among the most widely used fluorescent labels for preparing NIR fluorescent bioconjugates. Cy5.5 conjugates are very bright, photostable, and pH insensitive and produce minimal autofluorescence of biological specimens in this region of the spectrum. With a peak excitation at 678 nm and a maximum emission at 694 nm, Cy5.5 is spectrally almost identical to other near-IR dyes, including DyeLight 680™, IRDye™ 680 dye, and Alexa Fluor™ 680, and is ideal for multi-color applications.

    Abs/Em Maxima
    678/694 nm
    Extinction Coefficient
    Flow Cytometry Laser Line
    633 nm or 647 nm
    Microscopy Laser Line
    633 nm or 647 nm
    Spectrally Similar Dyes
    Alexa Fluor® 680, IRDye® 680RD, CF™ 680 Dye
    Molecular weight
    1039.18 (protonated)
    Water, DMSO, DMF
    >90% (HPLC)
    Blue solid
    Storage conditions
    -20°C. Desiccate
    Shipping conditions
    Ambient temperature

    Cy5.5 Maleimdie (also sold under sulfo-Cyanine5.5 Maleimide name) is a bright and photostable near-IR dye that is spectrally similar to Alexa Fluor® 680, DyLight® 680, and IRDye® 680 dye. Cy5.5 NHS Ester is completely water-soluble and often a reagent of choice for labeling antibodies, peptides, and proteins that are sensitive toward organic co-solvents. Cy5.5 conjugates are pH insensitive from pH 4 to pH 10 and produce minimal autofluorescence of biological specimens in this region of the spectrum. Fluorescence of this long-wavelength Cyanine dye is not visible to the human eye but is readily detected by most imaging systems.

    Cy5.5 spectrally is almost identical to Alexa Fluor® 680, CF® 680 Dye, IRDye® 680 or any other Cyanine5.5 based fluorescent dyes, and can be used as a less expensive alternative to these dyes.

    This sulfonated dye is also known as sulfo-Cyanine5.5 Maleimdie.

    DyLight® Alexa Fluor® is a registered trademark of Thermo Fisher Scientific. Cy®Dye is a trademark of GE Healthcare. IRDye® is a trademark of LI-COR Biotechnology.