Expanding the Fluorescence Toolbox

Improved Qdot® Probes Make Multiplexing Even Easier

(See a complete list of products discussed in this article.)

Whether you are tracking cells in vivo with Qtracker® Cell Labeling Kits, detecting cell-surface markers with primary antibody conjugates by flow cytometry, or staining cells with secondary antibody or streptavidin conjugates, Qdot® probes provide a revolutionary array of remarkably bright and photostable fluorescent labels for cell biology applications. Our recently improved Qdot® conjugates are now even brighter than before. Additionally, they offer reduced intensity differences between the different colors, simplifying multiplex applications when using violet-light excitation.

Enhanced Multiplex Capabilities for Fluorescence Imaging

Because of their broad excitation and narrow, symmetric emission spectra, Qdot® probes are well suited to multicolor analysis of multiple targets or events in a single sample. Qdot® probes can also be used to augment existing workflows that include organic fluorophores or fluorescent proteins for a heightened imaging experience (Figure 1).


Multiplex fluorescence imaging with Qdot® probes, fluorescent proteins, and organic dyes  
Figure 1. Multiplex fluorescence imaging with Qdot® probes, fluorescent proteins, and organic dyes.  Live human osteosarcoma (U2OS) cells were transduced with CellLight® Plasma Membrane-GFP, BacMam 2.0 (green), labeled using the Qtracker® 655 Cell Labeling Kit (magenta), and counterstained with HCS NuclearMask™ Blue Stain (blue). This image is a maximum intensity projection of Z-stack images collected on a Zeiss® LSM confocal microscope.

Advantages for Flow Cytometry

Qdot® probe–labeled primary antibodies offer many advantages for detecting cell-surface markers by flow cytometry (Figure 2), including compatibility with both 405 nm and 488 nm excitation sources, narrow emission spectra that require minimal compensation, and, unlike many tandem conjugates, chemical stability over time. 


Flow cytometry with Qdot® conjugates  
Figure 2. Flow cytometry with Qdot® conjugates. Lymphocytes gated from ammonium chloride–lysed human whole blood were stained with Qdot® 655 anti–human CD4 antibody (mouse monoclonal S3.5).

Explore the Full Range of Qdot® Probes

Qdot® probes are available with emissions in the visible, far-red, and near-IR spectral ranges—from Qdot® 525 to Qdot® 800, named for their peak emission wavelengths in nm—greatly extending the multiplex capabilities of your instrument platform.


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