Qdot® 565 Probe

Qdot® 565 probe is an excellent orange-fluorescent label with outstanding brightness and photostability for imaging and flow cytometry applications. With an emission maximum of ~565 nm, Qdot® 565 probe can be excited using a 350, 488, or 525 nm laser line or standard TRITC filter. Optimum imaging results with brighter signals are achieved with a Qdot® 565 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® 565 probe dashboard

Initial brightness



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



Photostability in buffer

  350, 488, 525
TRITC UV 565  
Laser line

Common filter set

Excitation max

Emission max

Qdot® 565 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.

HeLa cell staining with Qdot® probes.

HeLa cells were fixed and permeabilized, labeled with a biotinylated primary antibody against mouse alpha-tubulin, then stained with 20nM Qdot® 565 Streptavidin Conjugate (yellow), and 2 drops/mL NucBlue Fixed Cell Stain (blue). The image was acquired on a Nikon E800 upright microscope.

Qdot® 565 conjugation kits

We’ve developed functionalized versions of the Qdot® 565 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.