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Development of SERS-active Forensic Evidence Swabs for Rapid, Non-destructive Confirmatory Serological Screening and STR Typing of Human Bodily Fluids

NCJ Number
Date Published
January 2018
12 pages
Findings, methodology, and criminal justice implications are presented for a project that sought to develop surfaced enhanced Raman spectroscopy (SERS) - active forensic evidence swabs by attaching silver nanoparticles grown via hydrogen-reduction method to the fibers of commercially available swabs, so as to determine whether this procedure decreased the limit of detection of certain forensic samples.

The project also explored the Raman limit of detection of semen collected on swabs. This report concludes that the project confirmed the initial hypothesis that SERS-active swabs can be used to detect a human bodily fluid such as semen in a non-destructive procedure and enable DNA genotyping without degradation or interference. This is believed to provide further support for Raman spectroscopy as a valuable tool in forensic science; however, the research team will not affirm that SERS-active swabs have the potential to be operationalized, since the project was unable to resolve the issue of silver transfer from the swab to the substrate of the sample to be swabbed; therefore, it is unlikely that the forensic science community would use a technique that contaminates an evidentiary field of interest with a metal. Also, the swabs were found to be difficult to fabricate reliably, which creates issues of spectral data collection. Some researchers on the team had more success than others at fabrication, which suggests that small levels of contamination can impact the resulting silver surface and thus the ability for SERS enhancement. It may be possible that silver can be added to the swab after collection. This would eliminate the issue of contaminating the field. Materials and methods are described. 8 figures

Date Published: January 1, 2018