Staining is too light — cells hard to discern (Transwell Migration / Invasion Assay)

Question

Accepted Answer

Cells on the membrane are very faintly colored; impossible to count confidently or photograph clearly. Common causes: 1) Staining time was too short 2) Crystal violet concentration too low 3) Fixation time insufficient (cells not properly fixed for staining) 4) Over-washing removed stain 5) Cell number was intrinsically low Solutions: 1) Extend staining: 15 – 30 min in 0.1 % crystal violet 2) Use freshly prepared 0.1 % crystal violet 3) Ensure adequate fixation (15 – 20 min in 4 % paraformaldehyde) 4) Reduce wash count (2 – 3 gentle washes)