Qdot® 605 Probe

Qdot® 605 probe is an excellent red-fluorescent label with outstanding brightness and photostability for imaging and flow cytometry applications. With an emission maximum of ~605 nm, Qdot® 605 probe can be excited using 350, 488, 561, or 594 nm laser lines or standard TRITC filter. Optimum imaging results with brighter signals are achieved with a Qdot®  605 filter or light cube.

Made from nanocrystals of semiconductor material, Qdot® probes are broadly compatible with standard fluorescence techniques, but there are some novel aspects to their use that can be optimized to obtain the best possible results. In general they have an extremely broad excitation range and narrow emission with a large Stokes shift. Optimal brightness is generally achieved using a specific Qdot® filter.

Organic fluorophores and Qdot® probes can be readily combined in multiplexed flow cytometry or imaging studies. Longer-wavelength Qdot® probes are also ideal for multiplexed western blots.

Qdot® 605 probe dashboard

Initial brightness



For best results use a Qdot®-optimized filter and PBS or a mounting medium without antifade.



Photostability in buffer


Qdot® 605 products

The exceptional brightness and photostability of Qdot® probes make it easier to detect low-abundance targets. With narrow and symmetric emission spectra, Qdot® probes are also ideal for multiplexed fluorescence detection using a combination of Qdot® probes and organic dyes.

Flow cytometric analysis of whole blood cells using streptavidin conjugates of Qdot® nanocrystals.

Ammonium chloride lysed whole blood cells were stained with mouse anti human CD3 biotin, washed, stained with Qdot® 605 streptavidin conjugate, washed, stained with mouse anti human CD56 biotin, washed, and stained with Qdot® 705 streptavidin conjugate, washed, resuspended, and analyzed by flow cytometry using 405 nm excitation and detected using 605⁄20 nm and 710⁄20 nm emission bandpass filters. The dot plot shows Qdot® 705 streptavidin conjugate on the Y-axis and Qdot® 605 streptavidin conjugate on the X-axis.

Qdot® 605 conjugation kits

We’ve developed functionalized versions of the Qdot® 605 label for the preparation of custom conjugates of proteins and other biomolecules. The first—a carboxyl-derivatized form—can be coupled to amine groups of proteins and modified oligonucleotides. The second—an amine-derivatized PEG form—can be coupled to isothiocyanates and succinimidyl esters (or with native carboxylic acids using water-soluble carbodiimides).

Amine Aldehyde-, ketone, carboxylate or phosphate

Qdot® probes and accessories

Qdot® Probes are made from nanocrystals of semiconductor material and are broadly compatible with standard fluorescence techniques, but there are some novel aspects to their use that can be optimized to obtain the best possible results. Learn more about Qdot® Probes:


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.


Antifades and mounting media

Antifade reagentsHigh-performance antifade reagents like ProLong® Gold and SlowFade® Gold will inhibit the photobleaching of organic dyes but suppress the fluorescence of Qdot® probes. A better solution for imaging Qdot® probes is simply PBS or a clear, colorless toluene-based mounting medium formulated from acrylic resins without the addition of antifade components.


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.