Warning: This story includes references to sexual assault and may affect those who have experienced sexual violence or know someone affected by it.
There are almost half a million sexual assaults in Canada each year... and over 90% go unreported. Among the many factors influencing a victim’s decision to report is the notoriously slow turnaround of forensic samples. Research indicates that faster analysis of forensic samples could raise public confidence in reporting assaults.
This challenge is the focus of an article in Advanced Science, Toward Analysis at the Point of Need: A Digital Microfluidic Approach to Processing Multi-Source Sexual Assault Sample, authored by Professor Aaron Wheeler and a number of his current and former students. The multi-disciplinary effort uses microfluidics and the diagnostic lab-on-a-chip technology for which the Wheeler Lab is known.
The group collaborated with both industry and government, working with ANDE Corporation--who are specialists in rapid DNA analysis--as well as the Ontario Center for Forensic Science (CFS). “It was so much fun to work together,” Wheeler said. “They were critical contributors at every step of the project, and working with them was a terrific experience for the U of T trainees.”
ANDE and CFS provided much-needed expertise on the project, taking the work well beyond simple publication of an academic article. Both organizations have a deep understanding of the problems in the field, Wheeler explained, allowing them to point the research in meaningful directions.
Wheeler also highlighted the role of the National Sciences and Engineering Research Council (NSERC) in this project. “I am grateful to NSERC for having the foresight to establish the ‘Alliance Society’ program that funded this work, which has a mission to ‘address a societal challenge that will result in new natural sciences and engineering knowledge and societal impact.’”
The research behind the Advanced Science publication demonstrates a technique for automating and miniaturizing DNA analysis of evidence, on site and immediately after attacks.
MSc student Leticia Bodo was one of a team who first presented the work in poster format to the American Academy of Forensic Sciences (AAFS) Conference in Denver in February 2024. She was pleased with the positive feedback, which included winning the Young Forensic Scientists Forum (YFSF) Poster Award. “We received a lot of interest about our work, with people contacting both me and Mohamed Elsayed after the conference.”
Bodo explained the mechanism by which the forensic analysis device functions: “Sexual assault samples often have non-sperm cells and sperm cells. The device carries out the digestion of non-sperm DNA, leaving behind intact sperm cells. The digestion occurs when the device introduces an enzyme (DNase) that digests free-floating DNA by chopping it into fragments too small for analysis. The DNase cannot digest DNA inside intact sperm cells, so sperm DNA remains unfragmented. What remains can then be processed via short tandem repeat (STR) analysis, which determines an individual's DNA profile.”
Dr. Mohamed Elsayed, a postdoctoral fellow in the Wheeler Lab, began his work on the project while working on his PhD.
"We had access to very unique samples that closely mimic actual sexual assault case samples,” Elsayed explained. “This is important because if microfluidics solutions for this problem do not use these types of samples, forensic labs would be hesitant to adopt new methods without proper validation.”
He added: “As another first, the data show compatibility of the new technique with a so-called ‘Rapid DNA’ analyzer, designed for portability and ease of use in the field.”
The group is cautious about promising too much, too fast, but at the heart of this effort, Elsayed said, is victim empowerment. “I was astonished that most sexual assaults are not reported. The reason for the low reporting is diminished victim autonomy – that is, the victim has no information about the samples taken nor what will happen after the assault is reported.”
He expressed hope that eventually speeding turnaround on forensic results could be especially empowering for racialized victims of assault, and members of communities who do not trust law enforcement agencies. If case samples can be analyzed closer to the point of need, reducing the delays associated with evidence gathering and analysis, results might come back in as little as a few hours, as opposed to spending weeks—or longer—bottlenecked in a provincial laboratory.
Reporting a sexual assault is a notoriously difficult experience, one that can mean describing the attack multiple times. If the victim comes out of a hospital with a report that at least confirms the presence of sperm cells, it can strengthen a potential case. “With more information regarding the evidence collected, we hope people can make better informed decisions with respect to reporting attacks.”
Funding was provided by NSERC Alliance Society and ANDE Corporation.
To read more about this research article and the Wheeler Group work, see the story at Arts & Science News.