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)

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"Structured PCR protocol demonstration with step-by-step operational guidance covering correct handling procedures that minimize contamination risk"

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"First-person benchwork demonstration of PCR workflow provides practical perspective on proper pipetting technique and sample handling to avoid cross-contamination"