CYTO-ID^® Red long-term cell tracer kit

The CYTO-ID^® Red Long-Term Cell Tracer Kit uses proprietary noncovalent cell labeling technology to stably incorporate a red fluorescent dye containing hydrophobic aliphatic chains into the cell membrane’s lipid bilayer. The dye may be loaded into cells by following the included protocol. The labeling buffer is isotonic for mammalian cells and contains no detergents or organic solvents. The appearance of labeled cells may vary depending upon the cell type from uniformly bright to punctuate. This difference is thought to relate to the extent of membrane internalization occurring after cell labeling. The CYTO-ID^® Red Tracer Dye fluorescence is independent of pH within normally encountered physiologic ranges and fluorescence intensity per cell is typically unaffected by the ultimate pattern of dye distribution. The CYTO-ID^® Red Tracer Dye is not toxic to cells, as determined using the benchmark MTT cell viability assay. The dye is well retained by cells for up to 96 hours after loading, and is passed to daughter cells upon mitosis. Since the dye does not covalently modify proteins within the cells, normal physiological responses are better preserved than with molecular probes based upon thiol-reactive chloromethyl-based or amine-reactive succinimidyl ester-based fluorescent dyes. Dual labeling is also possible using a variety of available CELLESTIAL^® dyes. Labeled cells can be visualized by epifluorescence or confocal fluorescence microscopy. Additionally, dye-labeled and unlabeled cell populations can be analyzed by flow cytometry. No transfer of fluorescence to adjacent cells was observed after a prolonged 96-hour incubation period. This is in stark contrast to Calcein AM and BCECF AM, which are only retained within viable cells for a few hours at physiological temperatures. The kit is suitable for a variety of applications including long term cell viability, cytotoxicity, cell adhesion, cell migration and cell-cell fusion studies.