Targeted-Ion Mass Spectrometry for the Identification of Forensically Relevant Biological Fluids and Samples from Sexual Assault Evidence
Date of Award
Phillip B. Danielson, Ph.D.
Keith Miller, Ph.D.
Jim Fogelman, Ph.D.
Michelle Knowles, Ph.D.
Nancy Lorenzon, Ph.D.
Forensic science, Proteomics, Serology
Forensic practitioners have long sought efficient and reliable means for identifying those samples that are best suited for successful genetic profiling. Traditional serological screening methodologies rely upon enzyme activity and antibody-based serological tests. These tests can be consumptive, laborious and costly while reliance on antibody-based serological testing can be prone to error. Positive results resulting from non-target biological fluids, the potential for cross- reactivity and non-specific binding events yield merely presumptive results. This has led forensic biologists to omit serological testing, at least in the case of sexual assault kit samples, in favor of Y-Screen assays. While these Y-Screen approaches achieve rapid screening of samples for the presence of a detectible male DNA, they do not provide any serological information and therefore lack critical investigative/biological context.
A more sensitive and accurate technology for the confirmatory identification of biological fluids would greatly bolster the weight of serological evidence presented in court and assist with more informed sample prioritization. A particularly promising approach combines high- specificity protein biomarkers with a target-ion mass spectrometry. Applying absolute quantitation of protein targets in the biomarker panel will enable forensic practitioners to make fuller use of serological information in their decision making on downstream analyses in order to improve the successful analysis of challenging sexual assault samples.
This research demonstrated the prevalence of false-positive results associated with antibody-based serological methods, developed and validated a multiplex targeted-ion mass spectrometry-based assay for the identification of six forensically relevant biological fluids, demonstrated improved sensitivity and specificity of mass-spectrometry based body fluid identification as compared to traditional techniques, developed a modified assay for seminal fluid compatible with sexual assault kit evidence and evaluated the relationship between quantitative levels of target seminal fluid peptides and the ability to generate Y-STR profiles. These results provide the forensic and criminal justice communities with a powerful tool to aid in the criminal investigation of violent crimes.
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McKiernan, Heather Erin, "Targeted-Ion Mass Spectrometry for the Identification of Forensically Relevant Biological Fluids and Samples from Sexual Assault Evidence" (2019). Electronic Theses and Dissertations. 1675.
Received from ProQuest
Heather Erin McKiernan