Crystal Violet Staining (for Focus Formation Assay)

Place plates on ice.

Wash two times with ice-cold 1X PBS.

Fix cells with ice-cold methanol (stored at –20^oC) for 10 minutes.

Aspirate methanol from plates, move off ice and add enough 0.5% crystal violet solution (made in 25% methanol and stored at room temperature) to cover bottom of plate.

Incubate at room temperature for 10 minutes.

Pour off crystal violet solution into a beaker (can re-use).

Carefully rinse plates in ddH₂0 until color no longer coming off in rinse.

Allow plates to dry at room temperature (may take overnight).