Skip to content Skip to navigation

Forensic Research

Forensic Research

One out of every six American women has been the victim of a sexual assault in their lifetime. An investigative report in 2015 identified over 70,000 sexual assault kits from over 1,000 police departments (~6% of the police departments in the USA) that were not tested for DNA evidence. DNA casework backlog however continues to increase outpacing the nation's capacity since DNA evidence processing in sexual assault casework remains a bottleneck due to laborious and time‐consuming differential extraction of victim's and perpetrator's cells. Additionally, a significant amount (60–90%) of male DNA evidence may be lost with existing procedures.
To address these unmet challenges, we have developed a microfluidic method integrated with a bioinspired oligosaccharide sequence for selective isolation, differential extraction, and quantitation of sperm from the forensic evidence of heterogeneous cellular content in sexual assault kits (see the figure). Here, we present a method that (i) differentially isolates sperm and lyses them on‐chip, and extracts sperm DNA for downstream genetic analyses; (ii) reduces the differential extraction time from 8 h to 80 min; (iii) minimizes the need for manual labor; (iv) increases capture efficiency of immuno‐based separation of sperm assays from ~17% to ~70–92%; and (v) keeps this high efficiency for samples older than 15 years, representing a crucial direction to reduce the evidence backlog and providing an inexpensive alternative to current differential extraction techniques to accelerate identification of suspects and advance public safety.

Figure 1.