Giemsa Staining for Colony Formation Assay: An In Vitro Staining Procedure to Assess Proliferative Capability of Mesenchymal Stem Cells

To carry out the CFU assay, prepare 10 milliliters of Giemsa solution per dish, by using sterile water to dilute the stock solution 1 to 10. Remove the medium from the cell culture dish, and use PBS to carefully wash the cells.

With pure methanol, fix the cells at room temperature for 5 minutes, then, discard the methanol and add the Giemsa solution. Incubate in a humidified chamber at 37 degrees Celsius for 60 minutes. After the incubation, use PBS to wash the cells twice. Then, air-dry the plate head-first on a paper towel. With a marker on the back of the plate, manually count the colonies.