Trace cell collection techniques are vital for forensic DNA analysis, enabling recovery of small epithelial, blood, or tissue cell amounts from crime scenes. These methods prioritize maximizing yield while minimizing contamination to generate viable profiles.
Core Techniques
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Swabbing: Use moistened (sterile water) flocked swabs for non-porous surfaces; dry swabs for porous materials (fabric, wood), applying gentle circular pressure.
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Adhesive Lifting: Clear tape or adhesive films lift cells from rough surfaces (tools, flooring) by pressing firmly and transferring to a collection card.
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Vacuum Sampling: Portable vacuums with sterile filters collect cells from large areas (car interiors, carpets) or hard-to-reach spots.
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Hard-Base Collectors: Rigid tools scrape cells from uneven surfaces (door handles, weapon grips) where swabs fail.
Key Features
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High Sensitivity: Recovers as few as 10–20 cells for successful DNA amplification.
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Contamination Control: Single-use tools, sterile PPE, and separate work zones prevent cross-contamination.
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Surface Versatility: Adapts to porous, non-porous, rough, or curved surfaces.
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Field-Efficient: Tools are lightweight and require minimal training for on-site use.
Scope & Applications
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Crime Scene Investigation: Collecting cells from weapons, clothing, fingerprints, or contact surfaces.
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Cold Case Reviews: Re-sampling old evidence with improved techniques to recover previously undetected cells.
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Sexual Assault Cases: Recovering trace epithelial cells from victim clothing or evidence.