Towards an affinity-free, centrifugal microfluidic system for rapid, automated forensic differential extraction

Area of Science:

• Forensic Science
• Biotechnology
• Microfluidics

Background:

• Sexual assault evidence often contains mixed DNA profiles, with victim's DNA being predominant.
• Differential extraction (DE) is crucial for isolating sperm DNA but is labor-intensive and prone to contamination and DNA loss.
• Current DE methods may not yield sufficient sperm DNA for accurate perpetrator identification.

Purpose of the Study:

• To develop a fully automated, microfluidic device for differential extraction of sperm DNA.
• To improve sperm DNA yield and reduce contamination in forensic samples.
• To streamline the DE process for faster and more reliable results.

Main Methods:

• Development of an enzymatic, 'swab-in' microfluidic device utilizing rotational forces.
• On-disc automation of timed reagent release, temperature control, and fluidic fractionation.
• Testing compatibility with enzymatic extraction and downstream analyses like PicoGreen® DNA assay and PCR.

Main Results:

• Demonstrated proof-of-concept for a centrifugal platform automating the DE workflow.
• Achieved complete, self-contained on-disc automation of the forensic DE process.
• Total processing time reduced to ≤15 minutes with improved sperm cell DNA yield.

Conclusions:

• The proposed microfluidic device offers a complete, automated solution for forensic differential extraction.
• This technology has the potential to enhance sperm DNA recovery and improve perpetrator identification in sexual assault cases.
• The system is compatible with enzymatic extraction and downstream DNA analysis techniques.