Fluorescence Activated Live Cell Sorting Protocol

Fluorescence-activated cell sorting (FACS) of live cells separates a population of cells into subpopulations based on fluorescent labeling. Sorting involves more complex mechanisms in the flow cytometer than a non-sorting analysis. Cells stained using fluorophore-conjugated antibodies can be separated from one another depending on which fluorophore they have been stained with.
For example, a cell expressing one cell marker may be detected using a FITC-conjugated antibody that recognizes the marker, and another cell type expressing a different marker could be detected using a PE-conjugated antibody specific to that marker. This is the basic task of flow cytometry.

Individual cells are "interrogated" by the laser as in a normal flow cytometer.
The machine is set up so that each cell enters a single droplet as it leaves the nozzle tip. This drop is given an electronic charge, depending on the fluorescence of the cell inside the drop.
Deflection plates attract or repel the cells accordingly into collection tubes.
Sorted cell populations are then analyzed to ensure successful cell sorting.
Sorted cells can then be cultured.

Include serum in buffers.
Avoid sodium azide in the buffers during staining as this can be toxic to cells and compromise the viability.
The experiment should be undertaken in aseptic sterile conditions to ensure the cells do not become contaminated.
It is not usually possible to do intracellular staining before sorting live cells, as the permeabilization requires damage to the cell membrane which would compromise the cell viability.

For research use only. Not for any other purpose.