Stotesbury, Theresa

Access to human blood for forensic research and training in bloodstain pattern analysis (BPA) can be difficult due to many ethical, safety and cost concerns. Mammalian blood alternatives can be sourced, especially from local and willing abattoirs, but some concerns remain, and the added difficulties of high variation and species-specific differences in cellular components pose other issues. Therefore, synthetic alternatives to human blood provide practical options for the BPA community. This thesis explores the use of alginate hydrogels as a base material for forensic blood substitute (FBS) development. Hydrogels are first explored as a suitable environment for DNA stability and functionality and compared to other polymer systems. The ability of DNA to remain intact while undergoing electrospray ionization (ESI) is also investigated. The FBS design focuses on mimicking the fluid properties and genetic capabilities of whole human blood – a material not developed in FBSs previously. ESI was used to develop microparticles (MPs) that serve as cellular components of human blood (the red blood cells – RBCs, and white blood cells – WBCs). The microparticles were ionically crosslinked using calcium to provide small MPs (RBCs) or covalently crosslinked with functional DNA to provide larger WBC-like functional particles. The integration of these novel MPs into alginate-based materials is optimized and their use in BPA scenarios is explored. The FBS is tested in BPA scenarios of dripping experiments, impact patterns, and the ability to extract and amplify the contained DNA. In addition, the stability (or shelf-life) of the FBS was also assessed. The FBS exhibited similar spreading ratios to blood and demonstrated feasibility in use for impact angle (a) determination and impact pattern creation. Importantly, the DNA contained within the FBS could be processed with analogous protocols used in DNA evidence processing, enhancing its applicability to BPA research and training.

Author Keywords: Alginate hydrogels, Bloodstain pattern analysis, Electrospray ionization, Forensic blood substitutes, Forensic materials, Synthetic DNA design

Dissolved organic matter (DOM) in oceans provides nutrients and ultraviolet radiation protection to microbes. Some DOM compounds can chelate with metals, including copper, controlling their transport and bioavailability in marine systems. As copper functions as both a nutrient and toxicant, studies into the chemical structures of Cu-ligands is important, however currently limited. In this thesis, the chemical composition of total and Cu-binding DOM is investigated using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) in the Canadian Arctic and North Pacific. Chapter 2 reveals chemical differences in DOM composition between the southern and northern Canada Basin, revealing the influence of terrestrial and biological sources. Chapter 3 shows the uniqueness of Cu-binding ligands found in the Canadian Arctic and North Pacific Ocean. Studying the composition of DOM gives insight into the chemical diversity of marine DOM, helping to predict the effects of a changing climate on marine ecosystems.

Author Keywords: biological, dissolved organic matter, fluorescence, immobilized metal-ion affinity chromatography, mass spectrometry, terrestrial

Chemical presumptive tests are used as the primary detection method for latent bloodstain evidence. This work focuses on developing a forensic blood substitute which mimics whole blood reactivity to a luminol solution commonly used in presumptive testing. Designing safe and accessible materials that mimic relevant properties of blood is a recognized research need in forensic science. Understanding the whole blood dynamics related to reactivity with presumptive testing chemicals is important for developing accurate analogues. Provided in this thesis is a quantitative and qualitative characterization of photoemission from the reaction of a luminol solution to ovine blood. Luminol reactivity of a horseradish peroxidase encapsulated sol-gel polymer was validated against this ovine blood standard. This material, the luminol-reactive forensic blood substitute, is a key deliverable of this research. An optimized protocol for implementing this technology as a reagent control test, and as a secondary school chemistry experiment are presented. This thesis outlines the research and development of a forensic blood substitute as it relates to presumptive testing in bloodstain pattern analysis.

Author Keywords: bloodstain pattern analysis, forensic science, luminol, presumptive testing, secondary school education, sol-gel chemistry