Fluorescent-dye conjugated secondary antibodies provide a much needed tool for identifying proteins in many applications including fluorescent cell imaging, western blotting, immunohistochemistry and more. The advantages of using a fluorescently labeled secondary antibody include brighter signal, multiplexing capabilities, and ease of use (many are available for sale pre-conjugated to many different color of dyes). Thermo Fisher Scientific offers a wide selection of fluorescent-dye conjugated secondary antibodies for your research, with over 60 different fluorescent dyes and dye combinations, and nanocrystals in a wide range specific target and host species.


How to find a secondary antibody

Step 1: Search for the target species of interest (e.g., “anti-mouse” or “goat anti-rabbit” or “alexa fluor 488”).
Step 2: Narrow results by host species, conjugate, application, and other criteria using side filters.


Popular fluorescent secondary antibodies

Fluorescent secondary antibody selection guide

Featured fluorescent secondary antibody categories

Select from 18 different individual Alexa Fluor dyes and 4 Alexa Fluor tandem dyes as secondary antibody conjugates. Alexa Fluor secondary antibodies exhibit superior brightness and photostability, outperforming conventional fluorescent secondary antibodies. 

Find secondary antibody conjugates of traditional fluorophores such as fluorescein (FITC), tetramethylrhodamine (TRITC), Rhodamine Red, Cy3, Cy5, and Texas Red dyes.

Compare the technology

See how classical fluorophore, Alexa Fluor, and Alexa Fluor Plus secondary antibody conjugates compare.

  Classical fluorophore
conjugates
Alexa Fluor
conjugates
Alexa Fluor Plus
conjugates
What are they? Affordable, traditional dyes conjugated to secondary antibodies Bright and stable industry-leading dyes conjugated to secondary antibodies Innovative, proprietary dyes conjugated to highly cross-adsorbed secondary antibodies
Signal-to-noise ratio Low Medium High
Photostability Varying levels of photostability, depending on dye Photostable Photostable
Specificity Various options available Various options available Highly specific, low cross-reactivity (highly cross-adsorbed)
Sensitivity and brightness Lower sensitivity and brightness compared to leading Alexa Fluor conjugates Widely recognized standard for brightness and sensitivity Improved sensitivity and brightness over leading Alexa Fluor conjugates in IF/ICC imaging and fluorescent western blotting
Research areas Designed for detection of high-abundance targets in research areas with easy-to-obtain samples Designed for detection of medium- to high-abundance targets in most research areas Designed for detection of low-abundance targets in research areas with hard-to-obtain samples, e.g., neuroscience
Range of linear detection Low Medium High

Alexa Fluor Secondary Antibodies

Alexa Fluor conjugates exhibit more intense fluorescence than other spectrally similar conjugates. The superior performance of Alexa Fluor dyes means you need less conjugate for optimal results. See a comparison of working concentration of selected secondary conjugates.

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