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Nanoscale Tools for Food Safety, Health, and Environment


<p><ol><li> Develop effective onsite sensor technologies for enhanced onsite detection of pathogenic agents and disease markers. We will develop signal enhancement strategies utilizing multifunctional nanoparticle to significantly improve the limit of detection (LOD) of lateral flow immunochromatography (LF-IC) assays. Various (E. coli, Salmonella sp., Shigella sp., Listeria, Staphylococcus, Yersinia) foodborne and disease causing pathogens will be examined to achieve a LOD of < 10 cfu/ml (conventional LOD in LF-IC systems is ~106 cfu/ml) for pathogen detection and to the pictogram/ml LOD of protein biomarkers for cancer screening.</li><li> Develop engineering tools to monitor signaling in live cells at single molecule resolution to understand intracellular signaling dynamics and cross-talk. In this aim we will use general purpose peptide biosensors to target specific kinase activity in live cells to monitor dynamic signaling events. Thus perturbation of signaling due to an environmental contaminant or a drug or a disease condition can be assessed and quantified by monitoring the degree of phosphorylation. Here we will monitor the effect of chlorinated volatile organic compounds on cell signaling with a potential implication in birth defects. We will use the same biosensor approach to monitor specific signaling pathways at different stages of cancer development and/or to assess the effect of drugs on signaling. </li></ol></p>

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Given the advances in materials and instrumentation there has been a significant improvement in the development of detection technologies. Sensors that can detect and quantify transcripts in live cells have also been developed (Lee et al., 2014). Nevertheless, given the complexity of the samples and the LOD expected and the need to perform this step at a rapid rate in the field, the area of sensors development is continually challenged. Sensors that can detect pathogens and toxins as low as a single cell in complex matrices at within a few minutes is the ultimate goal for the scientists and engineers involved in this technology development space. Devices for Food Pathogen Detection: Despite the fact that America's food supply is one of the safest in the world, 76 million cases of food borne illnesses, 325,000 cases of hospitalization and 5000 deaths have been estimated every year according to the Center for Disease Control (CDC). More recently the level of alertness has increased to counteract agroterrorism across the entire food chain, from farm to the table. The cost for the treatment and control is estimated to be between $1- 10 billion every year (Scallan et al., 2011). Part of the challenge facing the food industry, agencies, and institutions charged with protecting public health, is to develop appropriate strategies to identify contaminated products rapidly to ensure quality and safety at every step in the farm-to-consumer or farm-to-processing sequence. There is a universal need among regulators, food producers and/or processors, and researchers for rapid, precise, and accurate detection methods for foodborne pathogens (1 cell/25-325 g sample) and other foodborne hazards (Bhunia, 2014).While the development of sensor technologies is on the rise, a better understanding of the sensor materials in the context of biological interaction will help to develop sensors that are more specific and sensitive (Cho et al., 2014). Such accuracy is critical because of the zero-tolerance mandate. Sensitivity using conventional biosensors is in the range between 103-104 colony forming units (CFU)/ml. Labeled PCR products of various genes from one food borne pathogen could be probed on one DNA micro array to create a Multi-Locus micro array subtyping scheme for various food borne pathogens. To detect at 1 CFU/ml sensitivity, to be able to answer questions at the molecular level, micro and nano-based technologies should be examined in conjunction with the existing methods. In addition, bringing new and emerging sensor technologies and paradigms to the forefront will play a significant role in elucidating the complex structures and mechanisms involved in food and biological systems. The overall objective of this study is to utilize and integrate the concepts of biosensor and nanotechnology based methods to develop simple technologies that can be deployed onsite for rapid detection (< 30 minutes) of food pathogens at the lowest possible limit of detection (< 10 cfu/ml).Devices for Intracellular monitoring: The vascular system is one of the first organ structures to develop in an embryo. Vasculogenesis refers to generation of blood vessels de novo from mesodermal precursor cells, while angiogenesis refers to formation of new blood vessels from pre-existing blood vessels (Stainier et al., 1996; Dzubow et al., 2010). Vasculogenesis happens extensively during embryonic development, and studies over the last decade have convincingly demonstrated adult vasculogenesis (Drake, 2003). Although generation of blood vessels in adults is of rare occurrence, except during corpus luteum and wound healing, and widespread during tumorigenesis, it is possible that complex regulatory mechanisms involving 'switching on' and/or 'switching off' of critical angiogenesis/vasculogenesis pathways that are responsible for this transcriptional dynamism could dictate cell fate. The susceptibility of vascular cells to be imprinted has been studied in pregnancy-related disorders such as intra-uterine growth restriction, gestational diabetes and pre-eclampsia (Krause et al., 2009), and thus we hypothesize that vasculogenesis is heavily influenced by signaling and epigenetic mechanisms. While CVOCs such as trichloroethylene (TCE) among others and their metabolites have been implicated in regulating congenital cardiovascular defects (Dawson et al., 1993; Johnson et al., 2003), precisely how they induce changes in gene regulation, signaling pathways, and cellular functions during fetal heart development is unknown. Technologies that monitor kinase activity in live cells are rare. A critical first step in enhancing our understanding of signaling pathways is through methods that allow us to monitor signaling in live cells and in a quantitative manner.

Irudayaraj, Joseph
Purdue University
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