CellTrace™ Blue Cell Proliferation Kit, for flow cytometry (Invitrogen™)

The CellTrace Blue Cell Proliferation Kit is used for in vitro and in vivo labeling of cells to trace multiple generations using dye dilution by flow cytometry. The CellTrace Blue reagent is specifically designed for excitation by a UV laser (at 355 nm or 375 nm), and it can be easily multiplexed with reagents and antibodies excited by other commonly used lasers.

• Superior performance—bright, single-peak staining enables visualization of multiple generations
• Long-term signal stability—well-retained in cells for several days post stain
• Versatile—multiple colors available to easily combine with antibodies or markers of cell function, such as GFP
• Simple, robust staining protocol

Superior fluorescent staining
Successful proliferation analysis by dye dilution (see figure below) requires an extremely bright dye to distinguish fluorescently labeled cells from auto-fluorescence after several cell divisions. The intense fluorescent staining provided by CellTrace Blue dye enables the visualization of five or more generations of proliferating cells before the signal is overwhelmed by intrinsic cellular auto-fluorescence. Consistent, homogeneous staining results in very little fluorescence variation between cells in a population, so distinct generations can be seen without any requirement for complex modeling software.The recommended working concentration for peripheral blood mononuclear cells is 5–10 μM. However, as with all reagents used in flow cytometry, to achieve optimal signal, reagent titration is highly recommended.

Long-term signal retention
Unlike stains that label the lipid membrane of cells, CellTrace Blue stain easily crosses the plasma membrane and covalently binds inside cells where the stable, well-retained fluorescent dye provides a consistent signal, even after several days in a cell culture environment. CellTrace Blue dye binds covalently to all free amines on the surface and inside of cells and shows little cytotoxicity, with minimal observed effect on the proliferative ability or biology of cells.

Easy multiplexing with other fluorophores
The UV excitation and narrow emission of CellTrace Blue dye make it ideal for multiplexing as it lies outside the spectral emission profiles of most other dyes and fluorescent proteins.

Simple, robust staining protocol
The CellTrace Blue Cell Proliferation Kit contains convenient single-use vials of dry dye to permit small-scale experiments without preparing excess quantities of dye. A stock solution is prepared by dissolving the contents of a vial in anhydrous DMSO prior to use. To stain 1 mL of cells in protein-free medium, 1 μL of this stock solution is typically used. Cells should be stained for 20 minutes at room temperature with gentle agitation. A brief wash with complete medium will then quench any dye remaining in solution.