Fluorescent-Activated Cell Sorting (FACS) or Magnetic-Activated Cell Sorting (MACS) are most frequently used methods for cell purification. We’re routinely use both methods in research for purification of stem cell populations. We know that FACS can provide better purity and more possibilities for choice of markers. MACS is simpler and could be done by everyone on a bench. Many researchers make decision on FACS versus MACS, based on pilot experiments comparing cell purity, viability and functions. But, I didn’t see very good studies, which compare FACS versus MACS for separation of particular stem cell populations.

The recent study compares FACS versus MACS for purification of rat CXCR4+ mesenchymal stromal cells (MSC):

Although the purity of CXCR4+-MSCs sorted by the immunomagnetic bead purification method was lower than that by sterile flow cytometry, the influence on cell activity of the former was smaller, including improved cell viability and improved SDF-1α -induced chemotactic migration in vitro.

So, in their experiment FACS compromised MSC viability and function (chemotaxis). Well, the purity difference is very well known fact. Viability could be lower right after FACS, because more shear stress for the cells in fast flowing stream of fluidics. As far as I know, the viability should improve dramatically after FACS once you put sorted cells in culture. But, how FACS and MACS can affect specific stem cell function remains largely unknown.

So, although, study doesn’t give us more information about specific MSC functions, it provides some clue about using FACS or MACS.

Dear readers, I wonder if any of you did this kind of comparative studies? If so, please share your experience and thoughts with us! Maybe you know some published methodological studies, which compare FACS and MACS in stem cell research. Please share.