PCR污染和携带污染

Symptom

Unexpected products appear in negative controls or multiple samples show identical non-specific bands, indicating contamination from previous amplifications or environmental sources.

1. 1 Aerosol contamination from pipetting high-concentration PCR products
2. 2 Exogenous DNA contamination from shared pipettors or work surfaces
3. 3 Contaminated reaction tubes containing biological inhibitors or previous DNA
4. 4 Poor laboratory practices allowing amplicon carryover

1. 1 Use aerosol-resistant (filter) pipette tips for all PCR setup and product handling
2. 2 Use positive displacement pipettes to prevent aerosol generation
3. 3 Set up dedicated work area and dedicated pipettor exclusively for PCR setup
4. 4 Autoclave empty reaction tubes prior to use to eliminate biological contaminants
5. 5 Wear gloves during all reaction setup and change frequently
6. 6 Prepare fresh reagent solutions and use new tubes when contamination suspected
7. 7 Physically separate pre-PCR and post-PCR work areas

Related Video (3)

Bilibili (China-Accessible Mirrors) ★ 85

PCR protocol fundamentals—hands-on operation guide

"Hands-on PCR protocol demonstration that covers proper operational technique and equipment handling to prevent contamination during sample preparation and pipetting."

Bilibili (China-Accessible Mirrors) ★ 78

First-person PCR and gel electrophoresis demonstration

"First-person PCR workflow demonstration with gel electrophoresis showing practical benchwork procedures where aerosol contamination risks and proper technique are most visible."

Addgene ★ 72

Polymerase Chain Reaction (PCR) Protocol

"Standard PCR protocol walkthrough that establishes correct procedural execution and equipment use, providing baseline technique to compare against contamination-prone practices."