Adaptation of the DNAse I procedure to the Biomek® NXP robotic platform for more efficient and automated sexual assault sample processing

In the United States, there were an estimated 298,410 reported sexual assaults in 2016. Nationwide, there are untested sexual assault kits on the shelves of law enforcement agencies, despite the fact that sexual assault evidence is one of the most common types of evidence submitted to forensic laboratories. Thus, the Virginia Department of Forensic Science (DFS), like many forensic laboratories, is adopting new techniques, instrumentation and procedures to help reduce the backlog and expedite sexual assault case processing. The goal of this proposal is to adapt a modification of the widely used differential extraction procedure (DE) to separate sperm cells from non-sperm cells, to a specific robotic platform. The modified procedure utilizes the DNAse I enzyme for rapid elimination of non-sperm DNA carry-over into the sperm cell fraction thereby making the process more efficient and the resulting DNA profile data easier to interpret. The automation of this modified DE procedure will be designed as a subprogram, to be utilized prior to current robotic casework processing and thus, will integrate seamlessly into casework sample processes. Moreover, it will lessen the time expended by examiners in preparation of sexual assault samples for automated DNA purification and processing. Published and unpublished manual and automated protocols for this procedure will be used for the starting conditions, which will then be optimized for casework application using the Biomek® NXP automation platform and current DNA extraction chemistries using the DNA IQ™ System. Initially, a manual procedure will be developed that is compatible with current sexual assault sample DNA purification and downstream DNA profiling. Once the manual process is fully optimized, the procedure will be adapted to automation using the Biomek® NXP robotic platform. All method development and optimization will involve comparisons with current, unmodified (standard protocol) manual and semi-automated DE procedure using quantitative and qualitative metrics. The new modified differential extraction procedure utilizing DNAse I will be robustly and fully validated to ensure that DNA sample quality and quantity is either as good or superior to current manual and automated procedures.

Note: This project contains a research and/or development component, as defined in applicable law, and complies with Part 200 Uniform Requirements - 2 CFR 200.210(a)(14).

CA/NCF