Browsing by Subject "Immunoassay"
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Item The development of microbead-based immunoassays: an application of the electronic taste chip(2003) Rodriguez, Marc David; McDevitt, John ThomasThere are many people I would like to acknowledge for making graduate school a gratifying and challenging experience. First, I owe many thanks to my supervisor, Dr. John T. McDevitt, for his guidance and leadership from the very start. I have learned many valuable lessons, both on a scientific and personal level, from our discussions. I also hope to someday emulate his democratic nature and controllability during times of crises. Furthermore, I would like to express my admiration in the creativity and scientific-aptitude shown by Dr. McDevitt , Dr. Jason Shear, Dr. Eric Anslyn and Dr. Dean Neikirk in creating the “Electronic Taste Chip” project. I know someday, if not already, this research will come to fruition and benefit the lives of many people. Indeed, I am grateful to have been a part of this intriguing, cutting-edge technology. I would also like to acknowlege Dr. Dean Neikirk and coworkers for providing the McDevitt lab with a supply of silicon chips, Ginger Gillan for help in the early stages of immunology protocol development, and Jorge Wong who has contributed directly for the generation of the superporous beads as described in Chapters 3 and 4. Dr. Bruce Walker and Dr. William Rodriguez from the Harvard Medical School are thanked for useful discussion regarding infectious disease detection. I would also like to acknowledge the National Science Foundation IGERT Program for access to their research facilities at the University of Texas at Austin and the opportunity to meet with other excellent scientists. Although the classes and activities required more time, I feel I have gained an edge over others and feel as I am part of a very well respected program. Finally, I want to recognize my mother, father and sisters. Their support and belief in me has, and always will be, at the heart of my accomplishments.Item Microfluidics for bioanalytical research : transitioning into point-of-care diagnostics(2014-12) Scida, Karen; Crooks, Richard M. (Richard McConnell)In this dissertation, three different microfluidic devices with bioanalytical applications are presented. From chapter to chapter, the bioanalytical focus will gradually become the development of a point-of-care sensor platform able to yield a reliable and quantitative response in the presence of the desired target. The first device consists of photolithographically-patterned gold on glass bipolar electrodes and PDMS Y-shaped microchannels for the controlled enrichment, separation from a mixture, and delivery of two charged dyes into separate receiving microchannels. The principle for the permanent separation of these dyes is based on the concept of bipolar electrochemistry and depended on the balancing/unbalancing of convective and electromigrating forces caused by the application of a potential bias, as well as the activation/deactivation of the bipolar electrodes. Two different bipolar electrode configurations are described and fluorescence is used to optimize their efficiency, speed, and cleanliness of delivery. The second device is a DNA sensor fabricated on paper by wax printing and folding to form 3D channels. DNA is detected by strand-displacement induced fluorescence of a single-stranded DNA. A multiplexed version of this sensor is also shown where the experiment results in “OR” and “AND” Boolean logic gate operations. In addition, the nonspecific adsorption of the reagents to cellulose is studied, demonstrating that significant reduction of nonspecific adsorption and increased sensitivity can be achieved by pre-treating the substrate with bovine serum albumin and by preparing all analyte solutions with spectator DNA. The third device, also made of paper, has a novel design and uses a versatile electrochemical detection method for the indirect detection of analytes via the direct detection of AgNP labels. A proof-of-concept experiment is shown where streptavidin-coated magnetic microbeads and biotin-coated AgNPs are used to form a composite model analyte. The paper device, called oSlip, and electrochemical method used are easily coupled so the resulting sensor has a simple user-device interface. LODs of 767 fM are achieved while retaining high reproducibility and efficiency. The fourth device is the updated version of the oSlip. In this case, the objective is to show the current progress and limitations in the detection of real analytes using the oSlip device. A sandwich-type immunoassay approach is used to detect human chorionic gonadotrophin (pregnancy hormone) present in human urine. Various optimization steps are performed to obtain the ideal reagent concentrations and incubation time necessary to form the immunocomposite in one step, that is, by mixing all reagents at the same time in the oSlip. Additionally, improvements to the electrochemical detection step are demonstrated.