Acoustic Differential Extraction - ultrasonic DNA-extraction from sexual assault evidence

Mikael Evander, Katie M. Horsman, Christopher J. Easley, James P. Landers, Thomas Laurell, Johan Nilsson

Research output: Chapter in Book/Report/Conference proceedingPaper in conference proceedingpeer-review

Abstract

Isolation of the male and female DNA is one of the most important steps in obtaining the DNA profile of the perpetrator in sexual assault cases. The sample is obtained by taking a vaginal swab containing both epithelial cells from the female and sperm cells from the male from the victim. The purity of the extracted male fraction decides whether or not a single-source DNA profile of the suspect will be obtained or not. The existing techniques are have poor separation efficiency, time-consuming, labour-intensive and are neither easily automated nor integrated with further analysis steps.
A novel method of DNA extraction based on ultrasonic trapping, Acoustic Differential Extraction, has been developed. A microfluidic device using laminar flow valving and miniature PZT transducers retains the sperm cells while mobilizing the female fraction into a separate outlet. The device was evaluated using a mock sexual assault sample and the separated fractions were analyzed using quantitative PCR and STR-profiling.
A 16-fold enrichment of the male fraction, making an originally hard-to-detect-male DNA profile readily profiled, has been demonstrated. The STR-profiling of the male and female fractions showed a male fraction purity of up to 99 % making it possible to obtain a single-source DNA-profile of the suspect. The microfluidic format of the device makes it possible to downscale the sample time from 4-8 hours to 10 minutes. It is also possible to integrate this method with further downstream analysis steps necessarey for the full forensic DNA analysis.
Original languageEnglish
Title of host publicationInternational Congress on Ultrasonics
EditorsEwald Benes
PublisherInternational Congress on Ultrasonics
Pages151-151
Number of pages1
Volume1
Publication statusPublished - 2007
EventInternational Congress on Ultrasonics 2007 - Wien
Duration: 2007 Apr 9 → …

Publication series

Name
Volume1

Conference

ConferenceInternational Congress on Ultrasonics 2007
Period2007/04/09 → …

Subject classification (UKÄ)

  • Medical Engineering

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