Plated too dense — colonies merge into one another (Colony Formation Assay)

Question

Accepted Answer

Many colonies fuse together so individual colonies cannot be counted reliably; counts will be over- or under-estimated. Common causes: 1) Seeding density was too high for the well/dish size 2) Cells were not dispersed into single-cell suspension before plating Solutions: 1) Lower the seeding density and run a pilot to find the right cell number per well 2) Trypsinize thoroughly and pipette to ensure single-cell suspension before plating 3) Plate so each potential colony is clearly separated