MTT assay otherwise known as a cell proliferation assay is used to detect the growth or decline of a group of cells in a petri dish.

 

For MTT assay the desired cells were treated with a special chemical which can enter into the cells and form a complex which gives off a blue color. The formed color is dissolved by a special solvent. The dissolved color was later measured by a colorimeter. A colorimeter is a machine that measures color. If there is more color, that means the cells are alive and growing however, the opposite is true if there is less color.