Many functions in a lab-on-a-chip device such as heating, electrochemical sensing and electrophoresis require integration of microelectrodes. However, conventional techniques for microelectrode integration are either requiring expensive facilities, cleanroom environment or insufficient in resolution and microelectrode thickness. Microwires have also been integrated into LOC devices as microelectrodes. They are commercially available in a diversity of material. and diameter, with industrial production standard and mechanical strength comparable to bulk metal, which make them ideal candidate for microelectrode. Nonetheless a technique to integrate these microwires into complicated microelectrode patterns has not yet been developed. In this thesis, two microwire integration techniques based on xurography are developed for elastomer and rigid polymer. Copper, silver, platinum, carbon and Ni-Cr alloy microwires down to 15 µm with minimum spacing of 150 µm and controllable position in the height direction are successfully integrated. The microwire electrode can also be suspended in the middle of the microchannel with desired length and angle. Various applications are presented to demonstrate the versatility of the xurographic microwire integration process. / Thesis / Master of Applied Science (MASc)

Master of Science / Department of Physics / Nobel S. Rebello / Over the past 20 years there have been limited efforts to improve students’ interest and knowledge of electronics and to offer students experiences to integrate and apply their knowledge of electronics with experimental physics. None of the reform efforts cited in the literature have performed a careful assessment of student learning and attitudes, and most of them report anecdotal success. These programs share several commonalities. They typically have a capstone project experience in which students apply their knowledge and skills in electronics and instrumentation to a particular context. The KSU Physics Department has embarked on an endeavor to improve the PMI (Physical Measurement and Instrumentation) class taken by physics majors. Capstone project experiences for students in PMI will provide them with an opportunity to revisit experiments they completed in previous courses. They then apply the knowledge and skills in electronics and instrumentation learned at the beginning of the PMI course to automate these experiments. The use of LabVIEW and NI ELVIS provides a range of opportunities to students due to their visual interface and easy learning curve. However, they do have some disadvantages such as speed and resolution when compared to more traditional measurements with oscilloscopes. Three specific capstone experiences have been developed in PMI. These include saturated absorption in Rubidium, the Franck-Hertz experiment, and the speed of light measurement. In each case, students first complete the traditional experiments and then use NI ELVIS and LabVIEW to automate these experiments. Students are provided minimal explicit guidance in completing the capstone projects. These include one-page handouts describing the goals, basic procedures and questions that students have to answer for themselves. Comparing data from traditional experiments and those from automated using LabVIEW and NI ELVIS provides a context in which to discuss the trade-offs between the traditional and automated experiments. Future efforts include the development of more experiments as well as careful assessment of student learning and attitudes as a result of the capstone experiences in the PMI class. This project can potentially inform similar efforts at other institutions in the future.

THz spectroscopy is an emerging technique for studying the dynamics and interactions of cells and biomolecules, but many practical challenges still remain in experimental studies. We present a prototype of simple and inexpensive cell-trapping microfluidic chip for THz spectroscopic study of live cells. Cells are transported, trapped and concentrated into the THz exposure region by applying an AC bias signal while the chip maintains a steady temperature at 37 degrees C by resistive heating. We conduct some preliminary experiments on E. coli and T-cell solution and compare the transmission spectra of empty channels, channels filled with aqueous media only, and channels filled with aqueous media with un-concentrated and concentrated cells.

The purpose of this investigation is to find out suitability of the solar chimney natural ventilation system in a Zero Energy Lab located at the University of North Texas campus, to figure out performance of the solar chimney. Reduction in the heating and ventilation and air conditioning energy consumption of the house has been also analyzed. The parameters which are considered for investigation are volumetric flow rate of outlet of chimney, the absorber wall temperature and glass wall temperatures. ANSYS FLUENT 14.0 has been employed for the 3-D modeling of the solar chimney. The dimensions of the solar chimney are 14’2” X 7’4” X 6’11”. The flow inside solar chimney is found to be laminar and the simulation results show that maximum outlet volumetric flow rate of about 0.12m3/s or 432 cfm is possible from chimney. The experimental velocity of chimney was found to be 0.21 m/s. Density Boussinesq approximation is considered for the modeling. Velocity and temperature sensors have been installed at inlet and outlet of the chimney in order to validate the modeling results. It is found that based on simulated volumetric flow rate that cooling load of 9.29 kwh can be saved and fan power of 7.85 Watts can be saved.

Magnetic nanoparticle (MNP) combined with biomolecules in a microfluidic system can be efficiently used in various applications such as mixing, pre-concentration, separation and detection. They can be either integrated for point-of care applications or used individually in the area of bio-defense, drug delivery, medical diagnostics, and pharmaceutical development. The interaction of magnetic fields with magnetic nanoparticles in microfluidic flows will allow simplifying the complexity of the present generation separation and detection systems. The ability to understand the dynamics of these interactions is a prerequisite for designing and developing more efficient systems. Therefore, in this work proof-of-concept experiments are combined with advanced numerical simulation to design, develop and optimize the magnetic microfluidic systems for mixing, separation and detection. Different strategies to combine magnetism with microfluidic technology are explored; a time-dependent magnetic actuation is used for efficiently mixing low volume of samples whereas tangential microfluidic channels were fabricated to demonstrate a simple low cost magnetic switching for continuous separation of biomolecules. A simple low cost generic microfluidic platform is developed using assembly of readily available permanent magnets and electromagnets. Microfluidic channels were fabricated at much lower cost and with a faster construction time using our in-house developed micromolding technique that does not require a clean room. Residence-time distribution (RTD) analysis obtained using dynamic light scattering data from samples was successfully used for the first time in microfluidic system to characterize the performance. Both advanced multiphysics finite element models and proof of concept experimentation demonstrates that MNPs when tagged with biomolecules can be easily manipulated within the microchannel. They can be precisely captured, separated or detected with high efficiency and ease of operation. Presence of MNPs together with time-dependent magnetic actuation also helps in mixing as well as tagging biomolecules on chip, which is useful for point-of-care applications. The advanced mathematical model that takes into account mass and momentum transport, convection & diffusion, magnetic body forces acting on magnetic nanoparticles further demonstrates that the performance of microfluidic surface-based bio-assay can be increased by incorporating the idea of magnetic actuation. The numerical simulations were helpful in testing and optimizing key design parameters and demonstrated that fluid flow rate, magnetic field strength, and magnetic nanoparticle size had dramatic impact on the performance of microfluidic systems studied. This work will also emphasize the importance of considering magnetic nanoparticles interactions for a complete design of magnetic nanoparticle-based Lab-on-a-chip system where all the laboratory unit operations can be easily integrated. The strategy demonstrated in this work will not only be easy to implement but also allows for versatile biochip design rules and provides a simple approach to integrate external elements for enhancing mixing, separation and detection of biomolecules. The vast applications of this novel concept studied in this work demonstrate its potential of to be applied to other kinds of on-chip immunoassays in future. We think that the possibility of integrating magnetism with microfluidic-based bioassay on a disposable chip is a very promising and versatile approach for point-of care diagnostics especially in resource-limited settings.

Droplet-based microfluidics can be used to enhance stem cell-based therapy by creating cell-laden hydrogel encapsulations to increase engraftment and retention while providing protection from immune responses caused by the host environment. Current research involves gaining better control over therapeutic mechanisms and one focus is to understand the mechanisms behind cell egress. Control over egress is vital to determining how long cells remain in proximity to the therapeutic target. We propose a microfluidic platform capable of encapsulating cells in two subsequent steps in order to create a double emulsion structure around the cell. In this project, hydrogel-in-hydrogel microdroplets are successfully manufactured without the presence of an intermediate oil layer and are used to observe model NIH 3T3 cell egress. In studying cell egress from singly or doubly encapsulated microcapsules, we are able to better understand the mechanisms that drive egress. Specifically, we hypothesize that cells egress when close to the edge of the microcapsule. In a double emulsion, cells are naturally located away from the edge and closer to the center. Results show that double emulsion microdroplets significantly reduce cell egress but do not eliminate it.

<p>Living Lab är en öppen innovationsmiljö där innovationer samproduceras, testas och verifieras av användarna, tillsammans med företag och akademin i en kontext som representerar innovationens tänkta användningsområde. Genom samverkan kan olika värden skapas för företagen. Syftet med uppsatsen var att undersöka hur Living Lab skapar värde för företag och vilka värden företag kan identifiera ur de användarcentrerade aktiviteterna. Uppsatsen karaktäriseras av en kvalitativ ansats och grundar sig i en explorativ undersökning med djupintervjuer där fyra företag ligger till grund för uppsatsens resultat. Uppsatsen har visat att Living Lab skapat värden för företag genom att de fått mer tilltalande produkter, identifierat nya användarkategorier och samordnat resurser med företag. Living Lab är därmed värdeskapande för företag genom stöd för utvärdering, ny- och vidareutveckling av innovationer. Samverkan mellan användare, företag och akademin öppnar upp för ett kunskapsutbyte vilket skapar värde för företag då kompetensutveckling äger rum och en djupare kunskap om användarna kan erhållas</p>

Lab-on-a-chip (LOC) biological assays have the potential to fundamentally reform healthcare. The move away from centralized facilities to Point-of-Care (POC) testing of biological assays would improve the speed and accuracy of these, thereby improving patient care. Before LOC can be realized, a number of challenges must be addressed: the need for expert users must be abstracted away; the manufacturing cost of $5 per test threshold must be met; and the supporting infrastructure must be integrated down to an easily portable size. These challenges can be addressed with the deposition of microfluidics on CMOS chips. By designing application specific integrated circuits (ASICs) much of the automation and the supporting infrastructure needed to run these assays can be integrated into the chip. Additionally, CMOS fabrication is some of the most optimized manufacturing in industry today. One of the central challenges with LOC on ASIC is the signal acquisition from the microfluidics into the CMOS. Optical sensing of fluorescence is one form of sensing used for LOC assays. Despite a large literature, there has not been a strong demonstration of monolithic LOC fluorescence detection (FD) for low concentration samples. This work explores the limit-of-detection (LOD) for LOC FD through analysis of the signal and noise of a proposed acquisition channel. The proposed signal acquisition channel consists of an on chip photodiode and integrator based amplification circuits. A hand analysis of the signal propagation through the channel and the noise sources introduced by the circuitry, is performed. This analysis is used to establish relationships between different circuit parameters and the LOD of a hypothetical LOC device. The hand analysis is verified through simulation and the acquisition channel is implemented in: (i) the Austrian Microsystems 350nm CMOS process, (ii) discrete components. Testing of the CMOS chip revealed several issues not identified in extracted simulation; however, the discrete integrator demonstrated many of the trends predicted by the hand analysis and simulations and achieved a LOD of 7.2$\mu M$. This analysis provides insight into the engineering trade-offs required to improve the LOD, to enable more wide spread application of LOC FD.

This thesis was on the development of a high-throughput electrokinetically-controlled heterogeneous immunoassay (EK-IA) microfluidic chip for clinical application. Through a series of experimental studies, a high-throughput EK-IA was developed. This EK-IA was capable of automatically screening multiple analytes from up to 10 samples in parallel, in only 26 min. Flow control in an integrated microfluidic network was realized by numerical simulation of the transport processes. This EK-IA was successfully applied to detect E. coli O157:H7 antibody and H. pylori antibody from human sera with satisfactory accuracy. Simultaneous screening of both antibodies from human sera was also achieved, demonstrating the potential of this EK-IA for efficiently detecting multiple pathogenic infections in clinical settings. Preliminary work on the application of EK-IA to detect biomarkers of embryo development in embryo culture media also yielded good results. In addition to the experimental studies, the reaction kinetics of this microfluidic EK-IA has also been investigated, using both numerical simulation and a modified Damköhler number. Targeted towards a more sensitive assay, the influences of several important parameters on the reaction kinetics were studied. This EK-IA holds great promise for automated and high-throughput immunoassay in clinical environments.

This thesis was on the development of a high-throughput electrokinetically-controlled heterogeneous immunoassay (EK-IA) microfluidic chip for clinical application. Through a series of experimental studies, a high-throughput EK-IA was developed. This EK-IA was capable of automatically screening multiple analytes from up to 10 samples in parallel, in only 26 min. Flow control in an integrated microfluidic network was realized by numerical simulation of the transport processes. This EK-IA was successfully applied to detect E. coli O157:H7 antibody and H. pylori antibody from human sera with satisfactory accuracy. Simultaneous screening of both antibodies from human sera was also achieved, demonstrating the potential of this EK-IA for efficiently detecting multiple pathogenic infections in clinical settings. Preliminary work on the application of EK-IA to detect biomarkers of embryo development in embryo culture media also yielded good results. In addition to the experimental studies, the reaction kinetics of this microfluidic EK-IA has also been investigated, using both numerical simulation and a modified Damköhler number. Targeted towards a more sensitive assay, the influences of several important parameters on the reaction kinetics were studied. This EK-IA holds great promise for automated and high-throughput immunoassay in clinical environments.