Alexa Fluor® 405Alexa Fluor® 405 dye is a blue-fluorescent dye with excitation ideally suited for the 407 nm spectral line of the krypton laser or the 408 nm violet laser diode. Alexa Fluor® 405 dye is pH-insensitive over a wide molar range, helping ensure that you get stable signals in live-cell imaging applications.

Alexa Fluor® 405 conjugates exhibit an excitation maximum at 401 nm and emission maximum at 421 nm. It is particularly useful in multicolor applications, including flow cytometry and super-resolution microscopy using STORM.

For imaging low-abundance targets, such as neuronal tracing in fine outgrowths, an anti–Alexa Fluor® 405 antibody is available for signal amplification. Using this anti-dye antibody in conjunction with standard enzyme-mediated immunohistochemical methods can allow you to generate a more permanent, fade-free signal for light microscopy.

We offer Alexa Fluor® 405 dye conjugated to a variety of antibodies and peptides optimized for cellular labeling and detection. In addition, reactive dye forms and protein labeling kits are available to enable you to generate your own antibody conjugates or probes.

Alexa Fluor® 405 dye dashboard

Initial brightness

Alexa Fluor® 405 dye provides versatility in the blue channel for imaging and is compatible with the violet laser for flow cytometry. It is extremely useful in stochastic optical reconstruction microscopy (STORM) where it is used as an activator. It is also used to label conjugates for SIM.


Photostability in buffer


Photostability in antifade


Performance in SRM


Alexa Fluore® 405 fluorescence

Alexa Fluor® 405 conjugated to CD4, used to label 10,000 cells and optimized for signal-to-background ratio.

Alexa Fluor® 405 reactive dyes

Amine Aldehyde, ketone, carboxylate, or phosphate

Alexa Fluor® 405 protein/antibody labeling kits

Select an optimized labeling kit for your target antibody or protein:

Target protein Kit Cat. No.
Site-specific antibody labeling
<1–20 µg mouse IgG1 Zenon® Alexa Fluor® 405 Mouse IgG1 Labeling Kit Z25013
<1–20 µg mouse IgG2a Zenon® Alexa Fluor® 405 Mouse IgG2a Labeling Kit Z25113
<1–20 µg mouse IgG2b Zenon® Alexa Fluor® 405 Mouse IgG2b Labeling Kit Z25213
<1–20 µg rabbit IgG Zenon® Alexa Fluor® 405 Rabbit IgG Labeling Kit Z25313

Alexa Fluor® dye family

Illuminating research for over 15 years

Alexa Fluor® dyesAlexa Fluor® dyes are among the most trusted fluorescent dyes available today. In addition to superior performance, you’ll get a technical support team experienced in problem-solving, >50,000 published references, application and experimental tips, and protocols to help with experimental planning. For an outstanding research experience, choose Alexa Fluor® dyes.



Molecular Probes® Handbook

Molecular Probes HandbookThe 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

Antifade reagentsAntifade 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

Cell stain toolStain 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.


Fluorescence SpectraViewer

Fluorescence SpectraviewerPlot and compare spectra and check the spectral compatibility for common fluorophores including all the Molecular Probes® fluorescent probes. The Fluorescence SpectraViewer tool is formatted for both microscope imaging and flow cytometry applications.

For Research Use Only. Not for use in diagnostic procedures.