Browsing by Subject "Nanotechnology"
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Item Biotechnological Approaches To Enhance Halotolerance And Photosynthetic Efficacy In The Cyanobacterium, Fremyella Diplosiphon(2017) Tabatabai, Ben; Sitther, Viji; Biology; Doctor of PhilosophyGrowing concerns over dwindling energy supplies linked to nonrenewable fossil fuels have driven profound interest in biofuels as a clean and sustainable alternative. Cyanobacteria are a promising source of third-generation biofuel due to their fast generation time and high net biomass conversion. In this study, the effect of salinity stress on Fremyella diplosiphon, a model organism for studying photosynthetic pathways, was investigated and nanobiotechnological approaches undertaken to enhance its halotolerance and photosynthetic efficacy. Heat-induced mutagenesis resulted in a mutant strain that could survive in 20 g L-1 sodium chloride (NaCl) with no loss in pigmentation. To further enhance F. diplosiphon halotolerance, expression plasmids harboring the hlyB and mdh genes were overexpressed in the wild type resulting in two transformants that thrived in 35 g L-1 NaCl, the average salinity of sea water. In addition, no significant reduction in photosynthetic efficacy was detected in the halotolerant strains relative to the wild type. Total lipid content and fatty acid methyl ester composition of wild type and halotolerant strains were assessed for their potential as a production-scale biofuel agent. Methyl palmitate, the methyl ester of hexodeconoate (C16:0), was found to be most abundant in the wild type and transformants accounting for 60-70% of total FAMEs produced. Efforts to enhance the photosynthetic efficiency of the strains revealed that gold nanoparticle-derived surface plasmon resonance augmented culture growth and pigment accumulation. Cell-nanoparticles interactions were visualized using scanning and transmission electron microscopy. Our findings address two key challenges that cyanobacterial biofuel agents need to overcome: enhanced halotolerance and photosynthetic efficacy to minimize freshwater input and artificial light supply. These innovations have paved the way for an efficient cyanobacterial cultivation system for large-scale production of biofuel.Item Development Of Rapid Analysis System Based On Microwave-Accelerated Bioassay Technique For Point-Of-Care Applications(2015) Mohammed, Muzaffer; Aslan, Kadir; Chemistry; Doctor of PhilosophyThe release of biological and chemical agents into water resources, air, and soil, and even in remote areas causes loss of human life, significant damage to the economy and long term effects on environment and health. Biosensors are useful tools for the assessment and monitoring of environmental and health disasters caused by biological and chemical attacks, accidental release of harmful agents into water shed and food chain. The field of point-of-care systems has emerged rapidly in the last decade with the advent of portable medical devices and biosensors. However, these systems either lack sensitivity, speed to end point are costly. Thus, there are substantial research and development opportunities in this field. In this regard, microwave energy coupled with plasmonic nanoparticles has been successfully used to enhance the sensitivity and signal output from biological assays through a surface plasmon effect. This method is referred to as microwave-accelerated bioassays (MAB) and employs commercially available high throughput screening (HTS) plates or glass microscope slides, which are not designed for microwave heating that results in heterogeneous temperature rise across sample wells. In this research, we developed a new circular bioassay platform to be used with a small monomode microwave cavity powered by a 100 watt external generator. With multiple wells on the new platform, we can test for numerous analytes of interest simultaneously. Our new microwave cavity, with an external microwave generator, is smaller in size compared to conventional kitchen microwave ovens, and is portable and easy to operate. It can be powered by multiple sources, such as low power USB ports or a 12V/150 W power port in a vehicle for on-site sample collection and analysis. Our new biosensing system combines the sensitivity of laboratory based systems and speed of currently available point-of-care systems to generate data within few minutes. This system can be used for various applications such as environmental sensing at water management plants, ecosystem monitoring, and point-of-care diagnostic systems for health care emergencies and for on-field use by military forces.Item Enzymatic Signal Amplification Using Plasmonic Nanostructures For Applications In Bioenvironmental Science And Engineering(2015) Abel, Biebele; Aslan, Kadir; Biology; Doctor of PhilosophyIn this work, we report the combined use of enzymes with plasmonic nanostructures to design a new hybrid system (enzyme-nanoparticle) for applications in bio- and nanotechnology. In this regard, current enzyme/nanoparticle hybrid systems have certain drawbacks, such as, cost effectiveness, as well as lengthy and complex preparation procedures. Subsequently, there is a need for the development of new hybrid systems, which can be prepared in a facile and inexpensive manner and can be applicable to environmental sensing. In addition, the fundamental study of the interactions of plasmonic nanostructures with enzymes (i.e., hybrid systems) can lead to the improvement of the stability and increase the efficiency of enzymes used in bioenvironmental science and engineering. In this dissertation, several fundamental issues were investigated, which include: the comparison of enzyme immobilization methods and the effect of nanoparticle loading, the application of biologically relevant enzymes to the hybrid system, the use of variety of plasmonic nanostructures in the hybrid system for enhanced enzyme activity, and the potential bioenvironmental applications. It was observed from the results that the hybrid systems show good sensitivity and acceptable reproducibility. This can be employed as a screening tool for pesticides detection.