Qdot® Nanocrystals in Flow Cytometry

  • Flexibility—excited by 405 nm or 488 nm, maximizing violet laser use
  • Compatibility—combine with existing organic dyes, increase the number of detectable parameters
  • Stability—does not degrade over time like tandem conjugates, for greater reproducibility
  • Minimal single laser compensation—narrow emission spectra allow for minimal compensation when using a single excitation source

View all Qdot® conjugates

New Primary Antibody Conjugates

Description  Cat. No.  
Mouse CD19-QD655 Q10379 product detail
Mouse IgG1-QD655 Q10297 product detail
Human CD19-QD605 Q10306 product detail
Human CD20-QD655 Q10305 product detail

What are Qdot® Nanocrystals and How are they Used in Flow Cytometry?

What are Qdot® Nanocrystals?
Qdot® nanocrystals are nanometer-scale semiconductor particles with unique fluorescence properties that differ from those of typical dye molecules. The color of light that the Qdot® nanocrystal emits is strongly dependent on the particle size, creating a common platform of labels from green to red, all manufactured from the same underlying semiconductor material (Figure 1).

Qdot® nanocrystals have broad absorbance spectra that increase dramatically at shorter excitation wavelengths. Their emission peaks are narrow and symmetrical, and do not change with variations in the excitation source (Figure 2).  Qdot® nanocrystals are optimally excited by a UV or violet (405–407 nm) laser, although sufficient excitation can also be obtained with other sources as discussed below.

Take Your Flow Cytometry to the Next Level
Qdot® nanocrystal conjugates are increasingly used in multispectral flow cytometry.  The use of these nanocrystal conjugates will allow the addition of one to six colors, all excited from the violet laser. Qdot® nanocrystals provide the additional advantages of brightness and photostability.

Because of their physical properties, Qdot® nanocrystals are brighter than most organic fluorophores when compared to conventional dyes; Qdot® conjugates remain fluorescent under constant illumination, while conventional dyes photobleach to varying degrees. The fluorescence stability of a Qdot® nanocrystal translates to better stability of the reagent, and consequently of the stained sample, and also permits additional analysis steps after sorting.

 

Qdot® Nanocrystals in Flow Cytometry

Figure 1. Nanocrystals absorb light and then re-emit the light in a different color; the size of the nanocrystal determines the color. Seven different nanocrystal solutions are shown excited with the same long-wavelength UV lamp.


Qdot® Nanocrystals in Flow Cytometry


Figure 2. Extinction coefficients and emission profiles for selected Qdot® nanocrystals. Excitation is presented as extinction coefficient; emission is normalized to maximum peak height.

How Qdot® Nanocrystals Benefit Your Flow Cytometry

Greater Flexibility and Precision for Flow Cytometry
With new flow cytometry instrumentation allowing ever-expanding detection capabilities, Qdot® Nanocrystals add an exciting new array of fluorescent labels for use in flow cytometry. Qdot® Nanocrystals provide fluorescent labels that can be excited with UV or violet light as well as longer-wavelength light sources, and exhibit long effective Stokes shifts and relatively narrow emission peaks. The result: greater flexibility and precision in designing multicolor flow cytometry panels.

Maximize Your Flow Cytometry
As the exclusive provider of Qdot® Nanocrystal technology for life science research, Invitrogen offers the full range of tools, from our new primary antibody conjugates to secondary detection reagents, required to maximize the use of your flow cytometer by combining Qdot® Nanocrystal technology with existing organic fluorophores.