Separation of sperm and epithelial cells based on the hydrodynamic effect for forensic analysis

Area of Science:

• Forensic Science
• Biotechnology
• Microfluidics

Background:

• Sexual assault forensic samples contain mixtures of sperm and victim epithelial cells.
• Current differential extraction methods are time-consuming and labor-intensive.
• Efficient separation is crucial for obtaining perpetrator DNA profiles.

Purpose of the Study:

• To develop a rapid and automated microdevice for separating sperm and epithelial cells.
• To improve the efficiency of forensic sample pretreatment in sexual assault cases.
• To enable faster and more accurate DNA profiling.

Main Methods:

• Fabrication of a microdevice utilizing hydrodynamic and size-based separation principles.
• Introduction of cell suspensions into microfluidic channels for differential flow.
• Collection of separated sperm cells from an outlet reservoir.

Main Results:

• Successful separation of sperm and epithelial cells within 0.5 hours for a 50-μl mock sample.
• Obtained a highly purified male DNA fraction (94.0% male fraction) from the sperm outlet.
• Demonstrated the potential for integration with subsequent DNA analysis units.

Conclusions:

• The developed microdevice offers a low-cost, rapid, and automated solution for sperm-epithelial cell separation.
• This technology significantly enhances the analysis of sexual assault evidence.
• The microdevice has broad applications in other cell sorting fields.