Formaldehyde fixation for flow cytometry

Contributed by Martin Fitzpatrick, University of Birmingham, United Kingdom

Alternative fixation procedure for FACS fixation, using formaldehyde fixatice.

• Fix cells with 2% fresh formaldehyde in PBS for 5-15min, gentle rotation may

help to improve fixation

• Wash cells 2-3 times with PBS to remove all of the formaldehyde
• Resuspend cells in 300ul of PBS
• Add 700ul of 100% -20°C EtOH to permeabilize the cells - they can now optionally be stored for weeks at –20°C.
• Permeabilize cells with 0.1% TritonX-100 in PBS for 15min

This method is based, with permission, on an original protocol available here.