Fluorescein derivatives are the most common fluorescent reagents for biological research because of their high absorptivity, excellent fluorescence quantum yield, and good water solubility.
Fluorescein-based dyes and their conjugates have several performance characteristics that may facilitate or limit use in certain applications. Fluorescein displays:
|We offer a broad range of fluorescein conjugates and derivatives as well as a series of high-performance fluorophores with improved characteristics for labeling and detection.|
|Fluorescein is a bright green fluorphore that is sensitive to changes in pH and can photobleach rapidly unless an antifade agent is used. Anti-fluorescein antibodies can be useful in amplifying a weak signal.|
Photostability in buffer
Photostability in antifade
HeLa cells were fixed and permeabilized using several Invitrogen products Image-iT Fixation/Permeabilization Kit then incubated with Anti-ATP Synthase Subunit IF1 and GAM-FITC secondary Ab. Cells were counterstained with NucBlue Live and ActinRed 555 then mounted using ProLong Gold Antifade Mountant and imaged using the EVOS FL Auto Imaging System and a EVOS 40X Objective, coverslip-corrected
Fluorescein reactive dyes
Select dye-labeling chemistries for conjugation with the following reactive groups:
Fluorescein protein/antibody labeling kits
Select an optimized labeling kit for your target antibody or protein:
High-performance alternatives to fluorescein
The Invitrogen Molecular Probes Alexa Fluor 488 dye—with spectral properties and quantum yield nearly identical to those of fluorescein isothiocyanate (FITC)—produces brighter, more photostable conjugates. These conjugates are ideal for imaging and other applications requiring increased sensitivity and environmentally insensitive fluorescence detection.
For pH monitoring the Invitrogen Molecular Probes pHrodo Green dye is almost nonfluorescent at neutral pH and fluoresces brightly in acidic environments. Unlike fluorescein, the minimal dye fluorescence at neutral pH also eliminates the need for wash steps and quencher dyes because any non-internalized dye will be essentially nonfluorescent.
|Comparison of the relative fluorescence of goat anti–mouse IgG antibody conjugates prepared from Alexa Fluor 488 dye and from fluorescein isothiocyanate (FITC). Conjugate fluorescence is determined by measuring the fluorescence quantum yield of the conjugated dye relative to that of a reference dye and multiplying by the dye:protein labeling ratio.|
Molecular Probes Handbook
The significantly revised 11th Edition is the most complete fluorescence labeling and detection reference available. The Molecular Probes Handbook can help you achieve the best experimental results for your fluorescence labeling and detection experiments. View the handbook online or order your own copy.
Antifade reagents suppress photobleaching and preserve the signals of your fluorescently labeled target molecules. They offer excellent compatibility with a multitude of dyes across the spectrum, making them especially valuable tools for multicolor applications. For added convenience, some formulations include the nuclear counterstain DAPI, eliminating the need for a separate counterstaining step.
Cell stain tool
Stain your own cell by using our simulation tool to develop reproducible results with many of our signature fluorescent dyes. Develop your multiplexing strategy for antibody probes, reactive dyes, and counterstains to create your perfectly labeled fluorescent cell.
Plot and compare spectra and check the spectral compatibility for common fluorophores including all of the fluorescent probes from Thermo Fisher Scientific. The Fluorescence SpectraViewer tool is formatted for both microscope imaging and flow cytometry applications.
For Research Use Only. Not for use in diagnostic procedures.