Prion Transport in Porous Media: Influence of Electrostatic and Non-DLVO Interactions

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0826204/PedersenThis study addresses prions, the infectious agents in transmissible spongiform encephalopathies such as bovine spongiform encephalopathy ("mad cow" disease) and chronic wasting disease of deer and elk, represent a potential threat to human health. At present, our understanding of prion fate and transport in soils and subsurface environments is extremely limited, even though such an understanding is critical to assessing the risks associated with prions in the natural environment (e.g., from diseased carcasses, animal shedding, discharges from slaughterhouse and game processing septic systems) and in engineered systems (e.g., landfill disposal of carcasses and waste from eradication programs and meat recalls). The main objectives are to evaluate the interactions important in infectious prion protein transport through porous media; and determine the reversibility of prion protein deposition induced by chemical perturbations. The PIs will examine prion protein attachment to quartz and functionalized silica surfaces under varying ionic strengths with background electrolytes differing in cation valence. The contribution of physical straining to prion protein retention in porous media will be examined using ultrapure quartz grains of several median particle sizes and size distributions. Attachment will be examined in saturated column experiments and using a quartz crystal microbalance with dispersion, and will be interpreted within the framework of the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of colloid stability. Equations will be derived that describe the single-collector efficiency under low Péclet number conditions and electrostatic and van der Waals interaction interactions between spheres and rods. Broader impacts will be realized through enhanced K-12 education by designing, implementing, and evaluating an instructional unit on environmental engineering and science for middle-school students that is organized around inquiry- and discovery-based learning exercises. Developing this middle-school unit will continue an existing collaboration with a middle school science teacher that was initiated through the NSF Research Experience for Teachers program. The project team will leverage existing resources to reach their educational objectives such as UW's NSF-funded Delta Program in Research, Teaching, and Learning to provide opportunities for graduate students to develop skills in classroom teaching, preparation of instructional materials, informal education, teaching to diverse student audiences, teaching with technology and internships.