Concentrating forensic DNA sample extracts on the Microlab® STARlet using the Microlab® monitored multi-flow,...

Area of Science:

• Forensic Science
• Molecular Biology
• Analytical Chemistry

Background:

• Forensic DNA analysis relies on sufficient DNA quantity for amplification.
• Previous automated workflows at the Centre of Forensic Sciences (CFS) lacked sample concentration capabilities.
• Forensic samples not meeting amplification thresholds were previously not analyzed.

Purpose of the Study:

• To integrate a sample concentrating module, the Microlab® Monitored Multi-Flow, Positive Pressure, Evaporative Extraction ([MPE]2) unit, into an automated liquid handling system.
• To validate the [MPE]2 unit's performance for forensic sample concentration, assessing contamination and sample loss.
• To improve the yield of DNA profiles from challenging forensic samples.

Main Methods:

• Installation of the [MPE]2 unit on a Microlab® STARlet Automated Liquid Handler.
• Optimization of filtering parameters and assessment of contamination.
• Conducting mock casework studies using various forensic sample types (blood, cigarette butts, etc.).
• Concentration of DNA extracts using the [MPE]2 and subsequent amplification with AmpFLSTR™ Identifiler™ Plus.

Main Results:

• No evidence of cross-contamination or sample loss was observed during the concentration process.
• DNA profiles generated from [MPE]2 concentrated samples showed concordant results with similar peak heights compared to manual concentration.
• Successful integration of the [MPE]2 into routine casework.

Conclusions:

• The [MPE]2 unit effectively concentrates forensic DNA samples without compromising profile quality.
• The implementation of this technology significantly increased the number of uploadable DNA profiles to Canada's National DNA Databank.
• Automated sample concentration is a valuable addition to forensic DNA workflows, enhancing analytical capabilities.