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Cell Explorer™ Live Cell Labeling Kit *Blue Fluorescence*

Image of HeLa cells stained with Cell Explorer™ Live Cell Labeling Kit *Blue Fluorescence* (Cat#22606) in a Costar black wall/clear bottom 96-well plate. Cells were stained with Calcein UltraBlue™ for 30 minutes at 37 <sup>o</sup>C. Images were aquired using a fluorescence microscope using DAPI filter.
Image of HeLa cells stained with Cell Explorer™ Live Cell Labeling Kit *Blue Fluorescence* (Cat#22606) in a Costar black wall/clear bottom 96-well plate. Cells were stained with Calcein UltraBlue™ for 30 minutes at 37 <sup>o</sup>C. Images were aquired using a fluorescence microscope using DAPI filter.
Ordering information
Price ()
Catalog Number22606
Unit Size
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Additional ordering information
InternationalSee distributors
ShippingStandard overnight for United States, inquire for international
Storage, safety and handling
H-phraseH303, H313, H333
Hazard symbolXN
Intended useResearch Use Only (RUO)
R-phraseR20, R21, R22


Our Cell Explorer™ fluorescence imaging kits are a set of tools for labeling cells for fluorescence microscopic investigations of cellular functions. The effective labeling of cells provides a powerful method for studying cellular events in a spatial and temporal context. This particular kit is designed to uniformly label live cells in blue fluorescence. The kit uses a proprietary dye that gets enhanced fluorescence upon entering into live cells. The dye is a hydrophobic compound that easily permeates intact live cells. The hydrolysis of the weakly fluorescent substrate by intracellular esterases generates a strongly fluorescent hydrophilic product that is well-retained in the cell cytoplasm. Cells grown in black-walled plates can be stained and quantified in less than two hours. It can be readily adapted for high-throughput assays in a wide variety of fluorescence platforms such as microplate assays, immunocytochemistry and flow cytometry. It is useful for a variety of studies, including cell adhesion, chemotaxis, multidrug resistance, cell viability, apoptosis and cytotoxicity. The kit provides all the essential components with an optimized cell-labeling protocol.


Fluorescence microscope

ExcitationDAPI filter set
EmissionDAPI filter set
Recommended plateBlack wall/clear bottom


Component A: Calcein UltraBlue™1 vial
Component B: HHBS (Hanks' buffer with 20 mM Hepes)1 bottle (100 mL)

Example protocol


Protocol summary

  1. Prepare cells in growth medium
  2. Remove the medium
  3. Add Calcein UltraBlue™ working solution (100 µL/well for 96-well plates or 25 µL/well for 384-well plates)
  4. Incubate the cells at 37 oC for 30 minutes to 2 hours
  5. Wash the cells
  6. Examine the specimen under under fluorescence microscope with DAPI filter (Ex/Em = 360/445 nm)

Important notes
Thaw all the components at room temperature before starting the experiment.


Unless otherwise noted, all unused stock solutions should be divided into single-use aliquots and stored at -20 °C after preparation. Avoid repeated freeze-thaw cycles.

1. Calcein UltraBlue™ stock solution:
Add 20 µL of DMSO into the vial of Calcein UltraBlue™ (Component A) and mix well to make Calcein UltraBlue™ stock solution. Protect from light. Note: 10 µL of Calcein UltraBlue™ stock solution is enough for 1 plate. For storage, seal tubes tightly.


Add 10 µL of Calcein UltraBlue™ stock solution into 10 mL of HHBS (Component B) and mix well to make Calcein UltraBlue™ working solution. Note: Protect from light.  

For guidelines on cell sample preparation, please visit


  1. Remove the growth medium from the cell plates.

  2. Add 100 µL/well (96-well plate) or 25 µL/well (384-well plate) of Calcein UltraBlue™ working solution into the cell plate.

  3. Incubate the cells in a 37°C, 5% CO2 incubator for 30 minutes to 2 hours.

  4. Wash the cells with HHBS (Component B), and add growth medium or HHBS back to the cells.

  5. Image the cells using a fluorescence microscope with DAPI filter (Ex/Em = 360/445 nm).


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Authors: Lei, Bo and Chen, Xiaofeng and Han, Xue and Zhou, Jiaan
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