UMD Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/3
New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.
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Item FEEDBACK-CONTROLLED BIOELECTRONIC HYBRID SYSTEM ENABLED BY ELECTROGENETIC CRISPR(2023) Wang, Sally Patricia; Bentley, William E; Bioengineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)With the rise of concepts like the “internet of things” and the advances in electronic technologies, our lives have now been occupied with smart devices that easily communicate with one another. These devices, however, lack the ability to freely exchange information with the world of biology, since electronics and biology possess very different communication modalities. Recently, the field of “electrogenetics” was introduced by enlisting redox mediators like hydrogen peroxide as a novel signaling medium to facilitate the connection between electronics with biology. In this dissertation, we expanded the electrogenetic framework and established a complete network of Bio-Nano Things, which collectively allowed automated, algorithm-based feedback control of electrogenetic CRISPR activity. First, we engineered the abiotic/biotic interface in order to improve information transfer between electronics and biological systems. Inspired by nature, we created an “artificial biofilm” that immobilized living cells on the surface of the electrode by electrochemically assembling bacteria and thiolated polyethylene glycol (PEG-SH) to form a thin film. We then endowed the PEG-SH hydrogel with redox capabilities via conjugation to generate an interactive material that can autonomously synthesize hydrogen peroxide to initiate communication with a bacterial population. Additionally, a polycysteine-tagged Streptococcal protein G was introduced for PEG-SH hydrogel surface decoration to enable the recognition of cells and other biological molecules. Next, we developed oxyRS-based electrogenetic CRISPR to broaden the bandwidth of electrochemical signaling, allowing multiplexed transcriptional regulation on various genetic targets. These include two crucial quorum sensing genes that controlled the relay of electrochemical signals to a broader yet selective audience of microbial populations through quorum sensing communication. We then integrated the engineered interface with eCRISPR-mediated transcriptional regulation to present “Biospark”, a full electrogenetic system including custom-made hardware and software, for algorithm-governed automated control of gene expression. Finally, we demonstrated a network of Bio-Nano Things by connecting the Biospark system with another custom bio-electrochemical device and even users to achieve remote feedback control of eCRISPR activity and more importantly, multidirectional communication between living systems regardless of physical distance. Together, we believe this work represents a huge leap toward making “smarter” devices and networks that can seamlessly guide biological processes with electronic input and can spawn various applications in the fields of biotechnology.Item Unraveling Metarhizium interactions with insects, plants and microbes(2019) Lovett, Brian; St. Leger, Raymond J; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Metarhizium fungi have dual lifestyles as insect pathogens and as rhizospheric plant symbionts. Since these fungi can vary widely in their virulence and host-specificity, they provide a powerful model for host-pathogen interactions. Today, it is clear the greatest potential of these fungi lies in their application as transgenic biotechnologies. Biotechnologies are rightly subjected to increased scrutiny, and this dissertation seeks to assess the risks and benefits of applying transgenic Metarhizium fungi using bioinformatics. After sequencing the early-diverged generalist Metarhizium frigidum, comparative genomics has upended our understanding of the trajectory of Metarhizium evolution. Using a functional gene microarray, I assessed the impacts these fungi have on the soil microbial community, establishing a protocol for evaluating possible risks of applying transgenic entomopathogenic fungi. To inform the evaluation and development of next-generation transgenic Metarhizium strains in the future, I evaluated the specific mosquito immune response to Metarhizium pingshaense during early infection with and without Plasmodium falciparum (the human malaria parasite) using transcriptomics. A strain of this fungus engineered to express a potent arthropod-derived, insect-specific neurotoxin in mosquito hemolymph, was also evaluated for mosquito control efficacy in semi-field trials in West Africa. Together, this body of work offers a comprehensive view of the evolution of this fungal genus and how transgenic fungi interact with insects, plants and microbes. The results herein comprise a framework for evaluating the risks and efficacy of transgenic fungi.Item THE DATAFICATION OF EVERYDAY LIFE: CRITICALLY CONTEXTUALIZING THE “QUANTIFIED SELF” IN PHYSICAL CULTURE(2019) Esmonde, Katelyn Rebecca; Jette, Shannon; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The contemporary moment has been characterized as that of the “Quantified Self” (QS); a time in which the body is increasingly subjected to meticulous measurement in the service of generating data that will maximize individual potential through self-improvement. The QS is most readily associated with fitness tracking devices like the Fitbit that quantify various aspects of physical activity (i.e., steps taken, distance walked, heart rate, caloric intake/output). While these devices are often taken up as an individual fitness or health choice, institutions, through efforts such as workplace wellness programs, increasingly utilize them to survey and manage their workers’ health. Widespread use of these technologies is often positioned as a panacea for institutional and personal betterment. In this dissertation, I critically evaluate this assumption, by examining the emergence, nature, and influence of the QS, through a contextualization of the quantification of the physically (in)active body. This is an important undertaking given that the preoccupation with statistical measurement and metrics has seemingly de-emphasized the experiential and, often un-quantifiable, dimensions of physical activity. In light of these concerns, I seek to understand if these technologies are enhancing people’s lives and allowing them to become technologically self-actualized, if they are alienating people from their bodies and physical activity while subjecting them to even greater scrutiny from others, or both. This dissertation comprises three interrelated research studies, in which I draw on the theoretical tools of Foucauldian poststructuralism and sociomaterialisms. In the first study, I historically contextualize the QS, with a focus on how and why the physically (in)active body has been quantified. The second study is a sensory ethnographic study wherein I analyze women runners’ fitness tracking practices to explore how fitness tracking shapes their experiences of embodiment and emplacement. Finally, in the third study I interview key informants in the workplace wellness industry and study documents from workplace wellness programs and proponents. By examining the sociomaterial conditions of self-tracking, both historical and contemporary, this dissertation highlights the politics of self-tracking and the contingencies that are required to produce ‘self-evident’ and factual data about oneself.