Home › Failure Case Library › Black Spots on Membrane
Western Blot (Sigma Protocol) minor

Black Spots on Membrane

Symptom
Random black spots or speckles appear on the western blot membrane
Common Causes
  1. 1 Blocking reagent has clumped and antibodies are binding to aggregates
  2. 2 Contaminating enzymes present in sample or blocking buffer
Solutions
  1. 1 Filter the blocking reagent before use
  2. 2 Filter the blocking buffer to remove particulates
Related Video (3)
Cell Signaling Technology ★ 92
Western Blot Troubleshooting Guide
"Dedicated troubleshooting guide directly addresses membrane artifacts and diagnostic approaches for resolving Western blot defects including spot formation."
Bilibili (China-Accessible Mirrors) ★ 78
Western blot hands-on: Protein extraction through detection
"Hands-on protocol with explicit emphasis on troubleshooting common pitfalls will demonstrate proper blocking reagent handling and membrane preparation techniques."
Bilibili (China-Accessible Mirrors) ★ 75
Reliable and Reproducible Western Blot Results
"Technical methodology webinar focused on reliable and reproducible results through proper technique will cover blocking and antibody incubation best practices to prevent aggregation artifacts."
Source: sigmaaldrich.com ↗
← Back to all cases