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Browsing by Author "Holcomb, Ryan E., author"

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    Bioanalytical applications of capillary electrophoresis and microfluidics: from metabolomics to biofuels
    (Colorado State University. Libraries, 2010) Holcomb, Ryan E., author; Henry, Charles S., advisor
    Capillary electrophoresis (CE) and related microfluidic technologies are increasingly being utilized as state of the art analysis tools in the field of bioanalytical chemistry. The following dissertation highlights selected applications of CE and microfluidics for metabolomics and microalgal-based biofuels research. Metabolomics research focused on targeted metabolic profiling and fingerprinting of biofluids using both conventional and microchip CE. Metabolite analysis in biofluids was of interest as this can be a useful clinical tool for monitoring disease states and treatment efficacy. Initial work in this area focused on targeted metabolic analysis of the cardiovascular disease biomarker homocysteine (Hcys). In this work, serum Hcys was analyzed using microchip CE (MCE) coupled with pulsed amperometric detection. Using this system, Hcys could be resolved from other electrochemically active serum components in under a minute by employing appropriate separation conditions. Following this targeted metabolic analysis, research shifted to a more comprehensive metabolic fingerprinting study of dogs undergoing chemotherapy for diffuse large B cell lymphoma. Urine samples from diseased and non-diseased dogs were obtained at various clinical time points and analyzed using CE with UV detection. The resulting fingerprints were compared for differences in metabolite make-up using multivariate statistical techniques. In an attempt to conduct this type of research at the microscale, a MCE device was developed with an integrated electrode array detector for resolving the multiple components present in biological samples. Selective detection and electrochemical resolution of co-migrating analytes could be facilitated with this device via judicious choice of detection potential at the multiple working electrodes. Improvement in detection capability of this system compared to single electrode MCE systems should allow for its use in rapid metabolic fingerprinting and profiling analyses. The final area of research presented in this dissertation involved use of microfluidics for culturing and screening cellular lipid accumulation in microalgae exposed to various environmental stressors. A microfluidic device was developed which contained integrated valves for facilitating cell culture and conducting imaging assays on-chip. Lipid accumulation in stressed microalgae was determined using fluorescence microscopy techniques. Additional experiments were conducted using gas chromatography to determine the types of lipids being accumulated in these stressed microalgae.