Professor’s invention processes sexual assault data faster at lower cost

An invention created by Tracey Dawson Cruz, chair of the forensic science department, and James Landers of the University of Virginia will process DNA from sexual assault cases faster. Photo by Raelyn Fines

Naomi Ghahrai, Contributing Writer

A VCU professor’s invention will process sexual assault data for about $10,000 less and more than five hours faster than current methods.

Chair of the Forensic Science Department Tracey Dawson Cruz developed the device in collaboration with James Landers, a chemistry professor at the University of Virginia.

Backlog in processing DNA evidence from sexual assault cases is an issue in many cities. According to a 2017 study by Rebecca Campbell of Michigan State University, there are about 200,000 to 400,000 untested sexual assault kits in U.S. police departments. DNA evidence is generally collected in a rape kit or other sexual assault kit.

When sexual assault evidence is taken, it may contain both the perpetrator’s and the survivor’s DNA.

“One of the main reasons for the backlog is because of the amount of DNA mixtures inherent in sexual assault samples,” said Jordan Cox, senior research associate and lab manager who works in Dawson Cruz’s laboratory.

Dawson Cruz and Landers created a tabletop device about the size of a shoebox that separates cells from a mixture through the use of antibodies, chemicals and centrifugation — a technique that separates particles from solution. In order to use the device, an analyst would place a swab of DNA evidence on a plastic microchip that has different chambers, then insert the microchip into the device.

Tracey Dawson Cruz is holding the device that would process sexual assault data for about $10,000 less and several hours faster that current methods. Photo by Raelyn Fines

“[Our device] condenses several hours — 8, 9, or 10 work hours — that may spread across multiple days in a crime lab, to a hands-free analysis that happens in about 90 minutes,” Dawson Cruz said. “It takes the processing in lab from the very first step all the way through the point where the analyst will put [the DNA] on a sequencer for final interpretation.”

Dawson Cruz said the cost of hardware for her invention is about $1,550, rather than an estimated cost of $12,000 of laboratory instruments used in the traditional method.

The device is able to work with skin cells, buccal cells — which are from the cheek — saliva, vaginal epithelial cells and semen. Dawson Cruz says her research team has not done much work with blood.

“It doesn’t matter who the victim is or what their gender is,” Dawson Cruz said. “In this version of the device, if you have a sample that contains semen of sperm cells, those cells can be separated from the other cells that are not sperm.”

Dawson Cruz says one of the goals before commercializing the invention is to decrease the failure rate, which is currently around 5-10%. She also hopes to improve the time needed to process the DNA and to be able to separate more than two different types of cells, in the event of rape with multiple perpetrators.

“We are hoping over the next year or so to continue working on improvements in the chemistry and improvements in the time for processing,” Dawson Cruz said. “Hopefully, during that time, the VCU Innovation Gateway office will work on finding an industry partner that might be interested in licensing our patent to bring it to commercialization.”

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