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Full-Text Articles in Chemistry

Simple, Label-Free And Non-Instrumented Analyte Quantitation By Flow Distance Measurement In Microfluidic Devices, Debolina Chatterjee Aug 2014

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 …


Modified-Electrodes For Redox-Magnetohydrodynamic (Mhd) Pumping For Microfluidic Applications, Christena Kayl Nash Aug 2014

Modified-Electrodes For Redox-Magnetohydrodynamic (Mhd) Pumping For Microfluidic Applications, Christena Kayl Nash

Graduate Theses and Dissertations

A new microfluidic pumping and stirring technique was demonstrated for lab-on-a-chip applications. Microfluidics was accomplished via redox-MHD, which takes advantage of a body force (FB) that is generated when there is a net movement of ions in solution (j) in the presence of a perpendicular magnetic field (B), according to the equation FB = j×B. In this work the movement of ions in solution was generated using electrodes modified with the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) rather than a redox species in solution, which can interfere with analyte detection and with biological species. …


On Chip Preconcentration And Labeling Of Protein Biomarkers Using Monolithic Columns, Device Fabrication, Optimization, And Automation, Rui Yang Feb 2014

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 …


Polymer Micro- And Nanofluidic Systems For In Vitro Diagnostics: Analyzing Single Cells And Molecules, Swathi Reddy Pullagurla Jan 2014

Polymer Micro- And Nanofluidic Systems For In Vitro Diagnostics: Analyzing Single Cells And Molecules, Swathi Reddy Pullagurla

LSU Doctoral Dissertations

Polymer micro- and nanofluidic systems, with their critical dimensions, offer a potential to outperform conventional analysis techniques and diagnostic methods by enhancing speed, accuracy, sensitivity and specificity. In this work, applications of microfluidics have been demonstrated to address the existing challenges in stroke diagnosis, by mRNA expression profiling from whole blood within <20 min. A brief overview of various biomarkers for stroke diagnosis is given in chapter 1 followed by design and testing of individual microfluidic modules (chapter 2 and 3) required for the development of POC diagnostic strategy for stroke. We have designed and evaluated the performance of polymer microfluidic devices for the isolation of leukocyte subsets, known for their differential gene expression in the event of stroke. Target cells (T-cells and neutrophils) were selected from with greater purities, from 50 µl whole human blood by using affinity based capture in COC devices within a 6.6 min processing time. In addition, we have also demonstrated the ability to isolate and purify total RNA by using UV activated polycarbonate solid phase extraction platform. Polymer-based nanofluidic devices were used to study the effects of surface charge on the electrodynamic transport dynamics of target molecules. In this work, we report the fabrication of mixed-scale micro- and nanofluidic networks in poly(methylmethacrylate), PMMA, using thermal nanoimprint lithography using a resin stamp and surface modification of polymer nanoslits and nanochannels for the assessment of the associated electrokinetic parameters – surface charge density, zeta potential and electroosmotic flow. This study provided information on possible routes that can be adopted to engineer proper wall chemistry of polymer nanochannels for the enhancement or reduction of solute/wall interactions in a variety of relevant single-molecule studies.


Microfluidic And Nanofluidic Devices - Mixed Scale Systems For Bioanalytical Applications, Michael David Vincent Jan 2014

Microfluidic And Nanofluidic Devices - Mixed Scale Systems For Bioanalytical Applications, Michael David Vincent

LSU Doctoral Dissertations

Developments in the field of microfluidics and nanofluidics allow an experimenter to employ new analytical techniques. One direction in which the field is moving towards is developing new devices and or instruments on the smallest scale possible. One way in which this can be achieved is by using a combination of top-down and bottom-up technologies. Some of these top-down techniques have been used in other fields such as the use of photolithography to fabricate semiconductors. Photolithography is a top-down method used to create features normally on the micrometer scale, but in order to create nanometer size features another top-down method …