Toward Analysis at the Point of Need: A Digital Microfluidic Approach to Processing Multi-Source Sexual Assault...

Area of Science:

• Forensic Science
• Biotechnology
• Analytical Chemistry

Background:

• Forensic case samples from sexual assaults often contain mixed DNA profiles, complicating analysis.
• Current methods require laboratory-based separation of sperm and non-sperm DNA sources prior to short-tandem repeat (STR) profiling.
• Processing sexual assault samples can be time-consuming and resource-intensive.

Purpose of the Study:

• To develop and demonstrate an automated, miniaturized method for DNA separation from sexual assault samples.
• To evaluate the efficacy of digital microfluidics (DMF) for pre-processing forensic samples.
• To explore the potential for point-of-need analysis of sexual assault evidence.

Main Methods:

• Digital microfluidics (DMF) was employed for automated and miniaturized separation of DNA from sexual assault samples.
• Vaginal swab samples were collected at different time points post-coitus (PC): up to 12 hours and 24-72 hours.
• Short-tandem repeat (STR) profiling was performed on the processed samples.

Main Results:

• The DMF method successfully identified single-source (male) STR profiles from samples collected up to 12 hours PC.
• Mixed STR profiles were identified from samples collected 24-72 hours PC, indicating potential for further optimization or data deconvolution.
• The automated process demonstrated feasibility for sample pre-processing.

Conclusions:

• An automated, miniaturized sample pre-processing method using DMF for sexual assault samples has been demonstrated.
• This technology has the potential to enable processing of sexual assault samples outside of traditional forensic laboratories.
• Integration with Rapid DNA Analysis could facilitate point-of-need processing in various settings, such as hospitals and police offices.