Biomedical Engineering Masters Papers

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    A Microstrip Transmission Line RF Biosensor: A Biosensing Device to Measure the Interaction Between Microliter Aqueous Solutions and Radio Frequencies
    (North Dakota State University, 2024) Godfrey, Mary
    Biosensors exploring the interaction between electromagnetic (EM) energy and aqueous solutions have long been an area of research interest. Previous research designs have employed various experimental setups, testing device structures, and frequency ranges to determine if property changes occur within the aqueous solutions under test after/during exposure to (EM) energy. Previous works have identified needs in the field, including smaller experimental device dimensions, a requirement of nanoliter to milliliter sampling volumes, and the ability to gather repeatable and sensitive measurements. Research Aim 1: The following dissertation questioned: Is it possible to design a sensor capable of measuring levels of interaction between RF energy and aqueous samples with reasonable reproducibility, sensitivity, and repeatability, all while being small in dimension, inexpensive to produce, and requiring microliter sample sizes? Research Aim 2: If the abovementioned sensor can be designed and verified, can it be used to measure the interaction levels between a broadband sweep of radiofrequencies and aqueous lambda DNA? In response to Research Aim 1, a millimeter-sized, microstrip transmission line biosensor with a microliter well operating on a broadband radio frequency range of 1.0-17.0 GHz was designed, simulated, and experimentally verified. Aqueous solutions, including deionized water, Tris-EDTA buffer, and lambda DNA, were loaded into the microliter well, and non-ionizing RF waves were transmitted down the transmission line. S-parameters were measured in sets to determine the interaction between the aqueous solution under test and the broadband radiofrequency sweep. Reproducibility and sensitivity were calculated for experimental data sets. Experimental data demonstrated 1) the RF biosensor’s ability to repeatably measure increasing concentrations of aqueous solutions, for example, lambda DNA diluted in Tris-EDTA buffer, and 2) a high measurement sensitivity, with the highest error value observed being 0.36%. Addressing Research Aim 2, increasing concentrations of lambda DNA diluted in Tris-EDTA buffer were experimentally measured, and reproducible trends were observed. Overall, the RF biosensor design was verified and determined to be a valid solution for measuring interaction levels between radiofrequencies and aqueous solutions of microliter quantities.
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    Investigation on the antibacterial efficacy of titanium alloy coating compared to the bulk titanium alloy and steel
    (North Dakota State University, 2024) Safah, Jinan
    The advancements in medical operations and sciences have improved patient lives, but device-related infections and bacterial contamination remain significant concerns. Escherichia coli is a prominent bacterium causing various infections. Commonly used antibacterial materials in the health industry for surgical operations include silver, copper, zinc, titanium, and steel exhibit antibacterial properties due to their durability, corrosion resistance, and diverse applications. This study aimed to compare the antibacterial properties of titanium (Ti64), steel, and titanium coating on aluminum to inhibit the growth of Escherichia coli. The experiment utilized serial dilution and colony counting techniques to assess bacterial growth on the materials. Results showed that titanium has better antibacterial properties, with Ti64 coating on aluminum also displaying effectiveness but to a less extent. In contrast, steel was the least effective. The study highlights the need for further research to understand the underlying mechanisms of antibacterial behavior in these materials and their long-term efficacy in surgical operations, ultimately contributing to improved infection control in medical settings.
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    Aortic Stenosis and the Path to Polymer Valves
    (North Dakota State University, 2023) Van Auken, Kaitlyn
    All available heart valve medical devices on the market are made from biological tissues. The major drawback of using biological tissue is that it is prone to calcification, which is generally why the intervention was needed in the first place. There is also the limitation of lifetime of the device; because it is a biological material it is more prone to degradation, wear, and tear. This leaves room for improvement of the valve device, to move from a tissue valve to a polymer valve. There has been great promise with preliminary materials studies showing resistant to calcification and an almost doubling lifespan for a valve. However, none of this proposed polymer valves have gone through clinical testing and are in general still being bench- top studied. There is ample room for companies or research groups to explore medical device innovation relating to a polymer leaflet material.
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    Modal Analysis of Blood Flow in Brain Aneurysms
    (North Dakota State University, 2022) Kasperski, Davina Jane
    The evolution of blood flow is vital in understanding the pathogenesis of brain aneurysms. Several past studies have shown evidence for a turbulent inflow jet at the aneurysm neck. Although there is a great need for analyzing inflow jet dynamics in clinical practice, data summarized in noninvasive modalities such as Magnetic Resonance Imaging or Computed Tomography are usually limited by spatial and temporal resolutions, and thus cannot account for the hemodynamics. In this paper, Dynamic Mode Decomposition (DMD) is used to pinpoint the dominant modes of the inflow jet in patient-specific models of sidewall aneurysms. This paper aims to prove that the dynamic modes are inflow jet interaction with the distal wall in addition to the hemodynamics of the parent artery. Our work indicates that DMD is an essential tool for analyzing blood flow patterns of brain aneurysms and is a promising tool to be used in in vivo context.
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    EVCD, Targeting Beta Sheet Richness of Tumor Derived Extracellular Vesicles for Pancreatic Cancer Screening
    (North Dakota State University, 2022) Elamurugan, Santhalingam
    Pancreatic cancer is a deadly disease and a relatively uncommon form of cancer. However, it is projected to be the second leading cause of cancer deaths in the US by 2040. The 5-year survival rate of pancreatic cancer patients is 10 percent. Currently, there are no effective screening methods available. Extracellular vesicles are nanoparticles secreted by all cells and play versatile roles in human health. EVs can be used as a non-invasive biomarker for pancreatic cancer screening since they can be isolated from bodily fluids. Currently, single molecule biomarkers have been proposed for pancreatic cancer screening. They lack sensitivity and specificity. We studied the ‘collective attribute’ of protein secondary structures of EVs from two cancer (MiaPaCa2 and PANC-1) and one healthy cell line (HPNE). Protein secondary structures of EVs were studied using circular dichroism spectroscopy. We found that cancerous EVs contain more beta sheet rich proteins than non-cancerous EVs.
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    Fluorescent Detection of Secondary Structure in Pancreatic Cancer
    (North Dakota State University, 2022) Bauer, Aaron
    Pancreatic cancer has one of the highest mortality rates among all cancers largely due to the late-stage onset of symptoms and the lack of early detection methods. Extracellular vesicles (EVs) could serve the potential as the next biomarker for pancreatic cancer detection because they directly reflect the state and composition of their parent cells. This work aimed to generate a high-throughput assay by combining immunoprecipitation of EVs with -sheet staining by Thioflavin T (ThT) in a 96-well plate based off previous findings that ThT could be used to measure the elevated -sheet richness found in tumor-derived EVs. This research tested four different immunoprecipitation methods in a 96-well plate. Although this work was not able to successfully create a high-throughput assay, it offers insight to increase fluorescent sensitivity by using a fluorescent microscope and optimizing immunocapture of EVs by developing an improved mixing method in 96-well plate.