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Full-Text Articles in Physical Sciences and Mathematics
Developing 3d Printed Integrated Microfluidic Devices For Microchip Electrophoresis Separation Of Preterm Birth Biomarkers, Joule E. Esene
Developing 3d Printed Integrated Microfluidic Devices For Microchip Electrophoresis Separation Of Preterm Birth Biomarkers, Joule E. Esene
Theses and Dissertations
Preterm birth is a global health challenge and the leading cause of neonatal mortality. Each year, about 15 million babies are born preterm globally. Traditional tools that have been exploited for the detection of preterm birth biomarkers are expensive, time consuming, or lack multiplexing capabilities. The work described in this dissertation highlights techniques developed to detect preterm birth biomarkers rapidly and accurately in the effort to mitigate preterm birth risk. In this dissertation, I first demonstrated the use of stereolithography digital light processing-based 3D printing and microfluidics for the development of microfluidic devices that had microvalves for fluid control. I …
Developing Genotypic And Phenotypic Systems For Early Analysis Of Drug-Resistant Bacteria, Yesman Akuoko
Developing Genotypic And Phenotypic Systems For Early Analysis Of Drug-Resistant Bacteria, Yesman Akuoko
Theses and Dissertations
Antimicrobial resistance in bacteria is a global health challenge with a projected fallout of 10 million deaths annually and cumulative costs of over 1 trillion dollars by 2050. The currently available tools exploited in the detection of bacteria or their DNA can be expensive, time inefficient, or lack multiplex capabilities among others. The research work highlighted in this dissertation advances techniques employed in the phenotypic or genotypic detection of bacteria and their DNA. In this dissertation, I present polymethyl methacrylate-pressure sensitive adhesive microfluidic platforms developed using a time-efficient, inexpensive fabrication technique. Microfluidic devices were then equipped with functionalized monoliths and …
Sequence Specific Concentration And Labeling Of Bacterial Plasmids For Future Use In Detection Of Drug-Resistant Sepsis Cases Without Amplification, Robert L. Hanson
Sequence Specific Concentration And Labeling Of Bacterial Plasmids For Future Use In Detection Of Drug-Resistant Sepsis Cases Without Amplification, Robert L. Hanson
Theses and Dissertations
Rapidly diagnosing the precise drug resistance present in sepsis-inducing bacteria is a continuing need to maintain the efficacy of our medical systems. Diagnostics currently being developed for such scenarios are either sensitive or rapid, but not both. Sequence-specific single DNA molecule analysis could fill this gap if it could be adapted to work on smaller targets, similar to those produced by classical biological methods. In this work, I demonstrate that immobilized ssDNA in the appropriate hybridization buffer can rapidly pull its complementary sequence out of solution. I also demonstrate that such systems in a microfluidic chip can be used to …
Microfabricated Fluidic Devices For Biological Assays And Bioelectronics, Anna V. Bickham
Microfabricated Fluidic Devices For Biological Assays And Bioelectronics, Anna V. Bickham
Theses and Dissertations
Microfluidics miniaturizes many benchtop processes and provides advantages of low cost, reduced reagent usage, process integration, and faster analyses. Microfluidic devices have been fabricated from a wide variety of materials and methods for many applications. This dissertation describes four such examples, each employing different features and fabrication methods or materials in order to achieve their respective goals. In the first example of microfluidic applications in this dissertation, thermoplastics are hot embossed to form t-shaped channels for microchip electrophoresis. These devices are used to separate six preterm birth (PTB) biomarkers and establish a limit of detection for each. The next chapter …
3d Printed Microfluidic Devices For Bioanalysis, Michael J. Beauchamp
3d Printed Microfluidic Devices For Bioanalysis, Michael J. Beauchamp
Theses and Dissertations
This work presents the development of 3D printed microfluidic devices and their application to microchip analysis. Initial work was focused on the development of the printer resin as well as the development of the general rules for resolution that can be achieved with stereolithographic 3D printing. The next stage of this work involved the characterization of the printer with a variety of interior and exterior resolution features. I found that the minimum positive and negative feature sizes were about 20 μm in either case. Additionally, micropillar arrays were printed with pillar diameters as small as 16 μm. To demonstrate one …
Dna Capture Via Magnetic Beads In A Microfluidic Platformfor Rapid Detection Of Antibiotic Resistance Genes, David Hyrum Harris
Dna Capture Via Magnetic Beads In A Microfluidic Platformfor Rapid Detection Of Antibiotic Resistance Genes, David Hyrum Harris
Theses and Dissertations
Antibiotic resistant infections are a growing health care concern, with many cases reported annually. Infections can cause irreversible bodily damage or death if they are not diagnosed in a timely matter. To rapidly diagnose antibiotic resistance in infections, it is important to be able to capture and isolate the DNA coding for the resistance genes. This is challenging because bacteria are present in blood in minute concentrations. To enrich the DNA to detectable levels, I modified magnetic microbeads with ssDNA sequences complementary to the target DNA to capture the DNA via hybridization. I compared DNA capture efficiency in three different …
Development Of Affinity Monoliths In 3d Printed Microfluidic Devices For Extraction Of Preterm Birth Biomarkers, Ellen Kelsey Parker
Development Of Affinity Monoliths In 3d Printed Microfluidic Devices For Extraction Of Preterm Birth Biomarkers, Ellen Kelsey Parker
Theses and Dissertations
Preterm birth (PTB) is defined as birth before the 37th week of pregnancy and affects 15 million infants per year. Presently, there is no clinical test to determine PTB risk. A 3D printed microfluidic device is being developed as a clinical test for PTB risk via detection of a panel of biomarkers. A significant step is extraction of the PTB biomarkers from blood serum. In this work, I developed 3D printed microfluidic devices in which monoliths can be polymerized. Using the monolith as a solid support to attach antibody, I show that ferritin, one of the PTB biomarkers, can be …
Electrokinetically Operated Integrated Microfluidic Devices For Preterm Birth Biomarker Analysis, Mukul Sonker
Electrokinetically Operated Integrated Microfluidic Devices For Preterm Birth Biomarker Analysis, Mukul Sonker
Theses and Dissertations
Microfluidics is a vibrant and expanding field that has the potential for solving many analytical challenges. Microfluidics shows promise to provide rapid, inexpensive, efficient, and portable diagnostic solutions that can be used in resource-limited settings. Microfluidic devices have gained immense interest as diagnostic tools for various diseases through biomarker analysis. My dissertation work focuses on developing electrokinetically operated integrated microfluidic devices for the analysis of biomarkers indicative of preterm birth risk. Preterm birth (PTB), a birth prior to 37 weeks of gestation, is the most common complication of pregnancy and the leading cause of neonatal deaths and newborn illnesses. In …
Design, Fabrication, And Optimization Of Miniaturized Devices For Bioanalytical Applications, Suresh Kumar
Design, Fabrication, And Optimization Of Miniaturized Devices For Bioanalytical Applications, Suresh Kumar
Theses and Dissertations
My dissertation work integrates the techniques of microfabrication, micro/nanofluidics, and bioanalytical chemistry to develop miniaturized devices for healthcare applications. Semiconductor processing techniques including photolithography, physical and chemical vapor deposition, and wet etching are used to build these devices in silicon and polymeric materials. On-chip micro-/nanochannels, pumps, and valves are used to manipulate the flow of fluid in these devices. Analytical techniques such as size-based filtration, solid-phase extraction (SPE), sample enrichment, on-chip labeling, microchip electrophoresis (µCE), and laser induced fluorescence (LIF) are utilized to analyze biomolecules. Such miniaturized devices offer the advantages of rapid analysis, low cost, and lab-on-a-chip scale integration …
Immunoassays Of Potential Cancer Biomarkers In Microfluidic Devices, Jayson Virola Pagaduan
Immunoassays Of Potential Cancer Biomarkers In Microfluidic Devices, Jayson Virola Pagaduan
Theses and Dissertations
Laboratory test results are important in making decisions regarding a patient's diagnosis and response to treatment. These tests often measure the biomarkers found in biological fluids such blood, urine, and saliva. Immunoassay is one type of laboratory test used to measure the level of biomarkers using specific antibodies. Microfluidics offer several advantages such as speed, small sample volume requirement, portability, integration, and automation. These advantages are motivating to develop microfluidic platforms of conventional laboratory tests. I have fabricated polymer microfluidic devices and developed immunoassays on-chip for potential cancer markers. Silicon template devices were fabricated using standard photolithographic techniques. The template …
Simple, Label-Free And Non-Instrumented Analyte Quantitation By Flow Distance Measurement In Microfluidic Devices, Debolina Chatterjee
Simple, Label-Free And Non-Instrumented Analyte Quantitation By Flow Distance Measurement In Microfluidic Devices, Debolina Chatterjee
Theses and Dissertations
Rapid determination of the concentrations of molecules related to diseases can provide timely information for treatment options. However, most biomarker quantitation methods require costly and complex equipment. On the other hand, point-of-care systems have less complex instrumentation needs than laboratory-based equipment, but often provide less information; for example, biomarker presence or absence instead of concentration. A complete analysis setup addressing key limitations of both laboratory-based and portable systems is highly desirable. I developed microfluidic devices with visual inspection readout of a target’s concentration from microliter volumes of solution flowed into a microchannel. Microchannels are formed within polydimethylsiloxane (PDMS), and the …
On Chip Preconcentration And Labeling Of Protein Biomarkers Using Monolithic Columns, Device Fabrication, Optimization, And Automation, Rui Yang
Theses and Dissertations
Detection of disease specific biomarkers is of great importance in diagnosis and treatment of diseases. Modern bioanalytical techniques, such as liquid chromatography with mass spectrometry (LC-MS), have the ability to identify biomarkers, but their cost and scalability are two main drawbacks. Enzyme-linked immunosorbent assay (ELISA) is another potential tool, but it works best for proteins, rather than peptide biomarkers. Recently, microfluidics has emerged as a promising technique due to its small fluid volume consumption, rapidness, low fabrication cost, portability and versatility. Therefore, it shows prominent potential in the analysis of disease specific biomarkers. In this thesis, microfluidic systems that integrate …
Microfluidic Devices With Integrated Sample Preparation For Improved Analysis Of Protein Biomarkers, Pamela Nsang Nge
Microfluidic Devices With Integrated Sample Preparation For Improved Analysis Of Protein Biomarkers, Pamela Nsang Nge
Theses and Dissertations
Biomarkers present a non-invasive means of detecting cancer because they can be obtained from body fluids. They can also be used for prognosis and assessing response to treatment. To limit interferences it is essential to pretreat biological samples before analysis. Sample preparation methods include extraction of analyte from an unsuitable matrix, purification, concentration or dilution and labeling. The many advantages offered by microfluidics include portability, speed, automation and integration. Because of the difficulties encountered in integrating this step in microfluidic devices most sample preparation methods are often carried out off-chip. In the fabrication of micro-total analysis systems it is important …
Polymer Microfluidic Devices For Bioanalysis, Xuefei Sun
Polymer Microfluidic Devices For Bioanalysis, Xuefei Sun
Theses and Dissertations
Polymeric microchips have received increasing attention in chemical analysis because polymers have attractive properties, such as low cost, ease of fabrication, biocompatibility and high flexibility. However, commercial polymers usually exhibit analyte adsorption on their surfaces, which can interfere with microfluidic transport in, for example, chemical separations such as chromatography or electrophoresis. Usually, surface modification is required to eliminate this problem. To perform stable and durable surface modification, a new polymer, poly(methyl methacrylate-co-glycidyl methacrylate) (PGMAMMA) was prepared for microchip fabrication, which provides epoxy groups on the surface. Whole surface atom transfer radical polymerization (ATRP) and in-channel ATRP approaches were employed to …
Microchip Liquid Chromatography And Capillary Electrophoresis Separations In Multilayer Microdevices, Hernan Vicente Fuentes
Microchip Liquid Chromatography And Capillary Electrophoresis Separations In Multilayer Microdevices, Hernan Vicente Fuentes
Theses and Dissertations
In this dissertation, several microfabricated devices are introduced to develop new applications in the area of chemical analysis. Electrochemical micropumps, chip-based liquid chromatography systems and multilayer capillary electrophoresis microdevices with crossover channels were fabricated using various substrates such as poly(dimethylsiloxane) (PDMS), glass, and poly(methyl methacrylate) (PMMA). I have demonstrated pressure-driven pumping of liquids in microfabricated channels using electrochemical actuation. PDMS-based micropumps were integrated easily with channel-containing PMMA substrates. Flow rates on the order of ~10 µL/min were achieved using low voltages (10 V). The potential of electrolysis-based pumping in microchannels was further evaluated for pressure driven microchip liquid chromatography (LC). …
Microfluidic Electro-Osmotic Flow Pumps, John Mason Edwards
Microfluidic Electro-Osmotic Flow Pumps, John Mason Edwards
Theses and Dissertations
The need for miniaturized, portable devices to separate and detect unknown compounds has greatly multiplied, leading to an increased interest in microfluidics. Total integration of the detector and pump are necessary to decrease the overall size of the microfluidic device. Using previously developed thin film technologies, an electroosmotic flow (EOF) pump was incorporated in a microfluidic liquid chromatography device. An EOF pump was chosen because of its simple design and small size. EOF pumps fabricated on silicon and glass substrates were evaluated. The experimental flow rates were 0.19-2.30 microliters/minute for 40-400 V. The theoretical pump efficiency was calculated along with …
Polymer Microchips For Capillary Electrophoresis And Electric Field Gradient Focusing Of Biomolecules, Ryan Thomas Kelly
Polymer Microchips For Capillary Electrophoresis And Electric Field Gradient Focusing Of Biomolecules, Ryan Thomas Kelly
Theses and Dissertations
Polymeric materials have seen increasing use as microfluidic device substrates due to their low cost and the simplicity of templated fabrication procedures. I showed that poly(methyl methacrylate) (PMMA) microdevices could be enclosed in a boiling water bath, which allowed the seal to form more quickly than in conventional approaches, and enabled microchannels to remain hydrated throughout the bonding process. Microchip capillary electrophoresis (µ-CE) devices were fabricated using water-based enclosure, and a mixture of fluorescently labeled amino acids was separated in 30 s in these microchips. To create more robust capillary electrophoresis (CE) microdevices with improved separation performance, phase-changing sacrificial materials …