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Colony Formation Assay minor

Crystal violet stain is too dark — high background

Symptom
Entire dish is deeply purple; individual colony boundaries are blurred by background staining.
Common Causes
  1. 1 Staining time was too long
  2. 2 Crystal violet concentration was too high
  3. 3 Insufficient washing left residual dye
Solutions
  1. 1 Reduce staining time (15 – 20 min)
  2. 2 Lower crystal violet concentration (0.05 – 0.1 %)
  3. 3 Increase wash count (3 – 5 gentle rinses in water)
Related Video (2)
Bilibili (China-Accessible Mirrors) ★ 85
Colony Formation Assay — Step-by-Step Protocol (Bio-Techne)
"Explicitly covers crystal violet staining step with timing optimization, directly addressing the root cause of the failure case"
YouTube (Curated Tutorials) ★ 75
A Guide to the Colony Forming Cell Assay: Methods and Tips
"Provides comprehensive protocol with optimization tips throughout, including staining procedure to prevent background issues"
Source: xiaohongshu.com ↗
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