Fridge, Freeze or Fix

If you’ve processed and isolated your cell type of interest and suddenly realize that you can’t analyze your purified cells immediately by flow cytometry, we can recommend the following solutions:

  • Store your purified unstained cells at 2 - 8°C until the next morning. With some cell types, the cell viability may decrease, but your analysis can still proceed. For improved viability, resuspend your purified cells in the recommended buffer (i.e. Catalog #07905, 20144, 20104 or 20164), which has protein to help maintain better viability.
  • Your cells can be fixed prior to analysis, depending on the experimental end point. If you are not planning to use the cells in downstream assays, such as in vitro growth, try fixing the cells to extend the time between purification and analysis by flow cytometry. Fix cells in 4% formaldehyde for 30 minutes, washing and resuspending the sample in the recommended buffer, and storing the cells at 2 - 8°C. Long term storage in 4% formaldehyde is not recommended. NOTE: It is important to determine whether the antibodies used for analysis can still bind formaldehyde fixed cells. It may be preferable to stain your cells first, then fix and store at 2 - 8°C (in the dark) until ready for analysis.
  • For long term storage, freeze an aliquot of your cells for analysis at a later date. Although DMSO is the most commonly used cryoprotectant, to help maintain viability of specialized cell types, mFreSR™ (Catalog #05854) or CryoStor™CS10 (Catalog #07930) can also be used.