Crystal Violet Stain

From Genome@Yale

Phosphate buffered saline (PBS)
1% Paraformaldehyde in PBS (0.25g in 25mL PBS, microwave PBS until hot and add paraformaldehyde) 
0.5% Crystal violet solution. (Dissolve 0.5 g of crystal violet stain in 100mL deionized water. Filter and store at room temperature)

1. Wash cells 2 times with PBS.
2. Replace with PBS containing 1% paraformaldehyde for 15 minutes at room temperature.
3. Rinse twice with PBS.
4. Stain with 0.1% crystal violet (prepared in 10% ethanol) 15 minutes at room temperature.
5. Pour off the CV.
6. Gently wash the cells with deionized water from a wash bottle until the water no longer runs dark. If you are too rough with the cells at this stage, they will come loose from the dish.
7. If you are staining cells within a culture well, simply withdraw the deionized water and let the stained cells dry.