alexa fluor 405 excitation shown as dotted line and emission shown as solid blue histogram
3407450/50401422(in buffer): 1
(in antifade): 4
microscopy, flow cytometry

Invitrogen Alexa 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.

See all Alexa Flour 405 Primary Antibodies   See all Alexa Fluor 405 Secondary Antibodies

labeled cells optimized for signal-to-background ratio

Figure 1: Alexa Fluor 405 conjugated to CD4, used to label 10,000 cells and optimized for signal-to-background ratio.

cells labeled with tubulin (cyan) and nuclei (magenta)

Figure 2: Immunofluorescent analysis of tubulin in U2OS cells. The cells were fixed with 4% fromaldehyde for 20 mins, washed 3x in PBS, permeablized with 0.5% Triton X-100 in PBS for 20 minutes, washed 3x in PBS and blocked with 3% BSA in PBS for 30 minutes. Cells were incubated with mouse anti-tubulin diluted in 3% BSA in PBS overnight at 4C and washed 3x in PBS. Cells were then incubated with Alexa Fluor Plus 405 Goat anti-mouse prepared in 3% BSA in PBS at a dilution of 1:250 in the presence of Sytox Deep Redat a dilution of 1:20k for 1 hour at room temperature followed by 3 washes in PBS. The images contain overlay of tubulin (cyan), and nuclei (magenta). Images were taken on an EVOS M7000 Imaging system at 20X magnification.

Additional resources


Flow cytometry protocols handbook

Protocols that fit your needs in flow cytometry ranging from sample preparation to numerous cell stimulation conditions, staining, immunophenotyping, and data analysis strategies.

Request the handbook



Fluorophore and reagent selection guide for flow cytometry

A handy reference poster featuring the broad range of our available dyes and labeling reagents.

Request the guide




Imaging protocol handbook

Protocols that fit your needs in imaging ranging from sample and assay preparation to staining, labeling, and data analysis strategies.

Request the handbook




Fluorophore and reagent selection guide for cell imaging

A tool for selecting the optimal fluorescent dyes for your Invitrogen EVOS cell imaging systems.

 Download the guide

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