Local blank patches / air bubble imprints

Symptom

Certain regions of the membrane show no signal at all, forming round or irregular blank zones; often due to transfer failure in those areas while surrounding bands look normal.

1. 1 Air bubbles trapped between gel and membrane during transfer
2. 2 Filter paper or sponges were not fully soaked
3. 3 Transfer sandwich was shifted or seated unevenly
4. 4 PVDF membrane was not properly pre-treated (not methanol-activated)

1. 1 When assembling, use a roller or a pipette to gently push out all air bubbles
2. 2 Fully pre-wet all transfer consumables (paper, sponges) in transfer buffer
3. 3 Check membrane and gel orientation; ensure they are properly aligned
4. 4 Activate PVDF in methanol for ≥15 seconds, then equilibrate in transfer buffer

Related Video (4)

Cell Signaling Technology

Western Blotting Protocol

Cell Signaling Technology ★ 92

Western Blot Troubleshooting Guide

"Western Blot Troubleshooting Guide directly addresses common failure modes including transfer-related defects that cause blank patches."

Bio-Rad Laboratories ★ 85

Quick Tips: Evaluating Western Transfers using Stain-Free Gels and Bio-Rad Imaging System

"Demonstrates transfer evaluation using Stain-Free imaging, enabling rapid detection of transfer failures like air bubble imprints before antibody staining."

Bilibili (China-Accessible Mirrors) ★ 78

Western blot hands-on: Protein extraction through detection

"Hands-on protocol with emphasis on troubleshooting pitfalls covers the transfer step where air bubbles become trapped between gel and membrane."