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An Automated Dielectrophoretic-Based Single Cell Separation Technique To Improve Laboratory Efficiency, Mixture Deconvolution and Combat Sample Inhibition

NCJ Number
253078
Date Published
Author(s)
Kevin S. Sweder, Michael A. Marciano
Annotation
This is the Final Technical Report on the findings and methodology of a study that examined whether and how an automated dielectrophoretic-based single cell separation technique (DEPArray) can improve forensic laboratory efficiency, mixture deconvolution, and combat sample inhibition.
Abstract
This study involved approximately 100 DEPArray runs, including those that focused on training, optimization, and experimental samples. The current data indicate that the method does not improve “touch” DNA analyses; therefore. project efforts focused on completing the sexual assault sample studies. The study demonstrated the readiness of the DEPArray for incorporation into casework analyses in forensic laboratories. Overall, this evaluation of the DEPArray concludes its limitations are outweighed by its advantages. The system provides a powerful and reliable method for analyzing sexual assault evidence, as it enables unprecedented sensitivity and specificity while eliminating the need for traditional confirmatory tests for human sperm and qPCR-based DNA quantification. Areas for improvement for DEPArray focus on cell loss during routing and recovery phases. There were instances in which sperm cells could not be recovered, because they were out of cage. As cells move to the main chamber, they have the potential to become un-routable due to their positioning (out of cage). This is due to the quality of the cell and inability of the cell to respond properly to the dielectrophoresis. The user can avoid losing cells by adjusting the speed in which the cages alternate the activity to move the cell electrophoretically. This report advises that the most critical factor in the effective operation of the DEPArray is the training and experience of the user. This applies to both the sample preparation and data analyses. Training suggestions are offered. 5 tables, 4 figures, and 5 references
Date Created: July 14, 2019