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) ★ 75

PCR practical operation video demonstration

"Extended hands-on PCR benchwork demonstrates workflow where contamination from high-concentration products can be visibly avoided with correct technique."

Bilibili (China-Accessible Mirrors) ★ 70

First-person PCR and gel electrophoresis demonstration

"First-person PCR with gel visualization directly shows how non-specific bands from contamination appear and how to interpret them."

Bilibili (China-Accessible Mirrors) ★ 68

Complete DNA Extraction to Gel Electrophoresis Protocol

"Complete workflow from extraction to gel includes PCR amplification, useful for seeing the full context where carryover contamination arises."