Forensic Lab-on-a-Disc for enhanced sperm cell purification in differential extraction workflows

Area of Science:

• Forensic Science
• Microfluidics
• Biotechnology

Background:

• Efficient sperm cell separation is crucial for forensic DNA analysis, especially in sexual assault cases.
• Conventional differential extraction (cDE) methods are laborious, time-consuming, and lead to DNA loss.
• Current methods often compromise DNA recovery and quality, impacting forensic investigations.

Purpose of the Study:

• To develop and validate a rapid, semi-automated method for sperm cell and non-sperm DNA separation.
• To improve DNA recovery, quality, and processing efficiency in forensic samples.
• To overcome the limitations of conventional sperm separation techniques.

Main Methods:

• Utilized a centrifugal microfluidic device (Forensic Lab-on-a-Disc) with tangential flow filtration and dual membranes (10 µm and 1 µm).
• Optimized filter pore size and washing cycles for maximal sperm recovery and minimal non-sperm DNA contamination.
• Compared the device's performance against conventional differential extraction (cDE) methods.

Main Results:

• The Forensic Lab-on-a-Disc achieved rapid sperm separation in approximately 6 minutes.
• Demonstrated significantly higher male DNA ratios and improved reproducibility compared to cDE.
• Successfully recovered male DNA with minimal non-sperm DNA carryover, even in high-ratio samples (1000:1).

Conclusions:

• The Forensic Lab-on-a-Disc offers a transformative solution for accelerating forensic DNA analysis in sexual assault cases.
• The device reduces operator variability and minimizes risks of non-sperm DNA carryover, improving mixture interpretation.
• This microfluidic approach enhances efficiency, reproducibility, and DNA recovery in forensic sperm separation.