Engineering Commons^™

A Three-Dimensional In Vitromodel Of Atherogenesis, Pin Hsuan Chang

Theses and Dissertations

Atherosclerosis is the narrowing of arteries caused by accumulation of cholesterol, calcium and other cellular debris in the inner arterial wall. While extensive studies have been focusing on the inflammatory mechanisms of the disease, pathological and experimental evidence has shown that regions of disturbed flow are susceptible to the atherogenesis. To further understand the relationship between hemodynamics and atherogenesis, this research aims to generate a dynamic, 3D in vitro model of atherogenesis. This will allow for the investigation of specific cellular and molecular mechanisms of plaque formation that will pave the way for new therapies for the disease. A novel …

Biological Implications Of Satellite Cells For Scaffold-Based Muscle Regenerative Engineering, Maggie R. Del Ponte, Charter Chain, Meng Deng Dr., Feng Yue Dr., Shihuan Kuang Dr.

The Summer Undergraduate Research Fellowship (SURF) Symposium

Satellite cells are anatomically localized along the surface of muscle fibers and have been regarded as a population of muscle-specific progenitors that are responsible for muscle regeneration. In response to muscle injuries, satellite cells are activated to enter the cell cycle, then proliferate and differentiate into mature muscle cells to regenerate damaged myofibers. Unfortunately, this natural repair mechanism is interrupted in conditions such as muscle degenerative diseases or volumetric muscle loss. The function of stem cells is regulated by signals from their local microenvironment which is called the stem cell niche. Current satellite cell-based strategies such as direct cell transplantation …

Using Collagen Binding Poly(N-Isopropylacrylamide) Nanoparticles To Prevent Intravascular Platelet Adhesion And Activation, Anna E. Searle, Alyssa Panitch, James Mcmasters

The Summer Undergraduate Research Fellowship (SURF) Symposium

Balloon angioplasty, the most prevalent non-surgical treatment for Atherosclerosis, damages the endothelial layer of the artery, baring an underlying collagenous layer, which causes platelet adhesion and activation and eventual thrombosis and intimal hyperplasia. Previous work in our lab has used a collagen-binding peptidoglycan, dermatan-sulfate-SILY (DS-SILY), that has been shown to bind to type I collagen and prevent platelet adhesion and activation. Our goal is to fabricate nanoparticle-SILY by cross-linking SILY to a poly(N-isopropylacrylamide) (NIPAm) nanoparticle instead of a DS backbone, while retaining the SILY’s high collagen binding affinity and platelet inhibition capacity observed in DS-SILY. Using a biotin-streptavidin assay, we …

Optimization Of Imaging Parameters To Determine Flow Velocity Using Nanoparticles, Sabrina M. Scalf, Haisheng Yang, Russell P. Main

The Summer Undergraduate Research Fellowship (SURF) Symposium

Microfluidic flow chambers have been developed and used to measure flow at the microscopic level. Nanoparticles can be used to track the fluid flow within the chamber and this allows for accurate velocity measures. Microscope parameters used for experimentation differ across various projects and resources; therefore, there is a need to determine the best combination of settings for the equipment at hand. Once appropriate settings are selected, images of the flow are captured with a confocal microscope and can be analyzed using custom written MATLAB code. A pair cross-correlation function is used to determine where the particles have traveled in …

Spatiotemporal Changes In Nuclear Strain Measured By Traction Force Microscopy, Ryan D. Watts, Corey Neu, Jonathan Henderson

The Summer Undergraduate Research Fellowship (SURF) Symposium

The knowledge of how cells interact with and sense their surroundings is missing the key components of time dependency and how substrate stiffness affects amount and rate of strain. This new knowledge of cell-substrate interaction can be applied further to research regarding chromatin spatiotemporal dynamics to better understand gene accessibility for transcription. Studying how the cell functions on a deeper level will provide understanding of cellular morphological changes and proliferation. This study uses the methods of optical microscopy and traction force microscopy (TFM) to image substrate deformation as well as analyze its strain profile to find where forces are interacting …

Thin-Film Sol-Gel As Controlled Delivery Platform For Neural Microelectrodes, Margaret A. Harden, Matthew D. Mcdermott, Kevin J. Otto

The Summer Undergraduate Research Fellowship (SURF) Symposium

Long-term efficacy of neural implantation devices is a persisting challenge in neural engineering and rehabilitation. Upon implantation of a neural device, the foreign body response (FBR) is triggered and glial cells form a sheath around the electrode array. This sheath isolates the array from the rest of the brain both mechanically and electrically. Tetramethyl orthosilicate (TMOS), a thin-film polymer, has been shown to not negatively impact the impedance and charge-carrying capacity, as well as offer a controlled delivery method to deliver pharmaceuticals to mitigate inflammation without significant effect to device design. Using an in vitro protein delivery model to analyze …

Tissue Engineering: Applications In Developmental Toxicology, Stephanie N. Thiede, Nimisha Bajaj, Kevin Buno, Sherry L. Voytik-Harbin

The Summer Undergraduate Research Fellowship (SURF) Symposium

In vivo toxicology assays are expensive, low-throughput, and often not predictive of a human response. Three-dimensional in vitro human cell-based tissue systems incorporating cell-cell and cell-matrix interactions have promise to provide high-throughput, physiologically-relevant information on the mechanism of the toxin and a more accurate assessment of the toxicity of a chemical before progression to human trials. Quantification of the disruption of vasculogenesis, the de novo formation of blood vessels from endothelial progenitor cells, can serve as an appropriate indicator of developmental toxicity since vasculogenesis is critical to the early development of the circulatory system. The current routinely used in vitro …

Multi-Channel Analysis For Gradient Artifact Removal From Concurrent Eeg-Fmri Studies, Miguel R. Castellanos, Zhongming Liu

The Summer Undergraduate Research Fellowship (SURF) Symposium

Concurrent electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) recordings are susceptible to large amounts of noise due to the static and dynamic magnetic fields present inside the MR scanner. EEG-fMRI studies are conducted to provide better spatial and temporal resolution for each recording, respectively, but the artifacts found in the EEG render the data impossible to interpret. Past studies have focused on signal post-processing techniques which are able to effectively remove noise upon the completion of a study, but there are no techniques able to process the data in real-time without extensive calibration. This research addresses this issue by …

Medical Applications Of Mrc, Kyle Thackston, Henry Mei, Pedro Irazoqui

The Summer Undergraduate Research Fellowship (SURF) Symposium

Consistent powering is a limiting reagent for many medical implants and sensors. Powering in-vivo devices in animal studies requires either transcutaneous wiring (limiting mobility and increasing the chance of infection) or an implanted battery (limited lifetime and limits size of device). Wireless power transfer (WPT) would be able to overcome these challenges and permit the use of more advanced implantable devices in a research setting. Magnetic resonance coupling (MRC), an advanced form of inductive charging, allows good transfer efficiencies over significant air gaps, but works best a specific location and frequency, limiting mobility in animal studies. Using band-pass filter theory, …

Three Dimensional Quantification Of Angiotensin Ii-Induced Murine Abdominal Aortic Aneurysms Using High Frequency Ultrasound, Amelia R. Adelsperger, Alexa A. Yrineo, Hilary D. Schroeder, Ashley Nicole Blaize, Katherine E. Wilson, Evan H. Phillips, Frederick W. Damen, Craig J. Goergen

The Summer Undergraduate Research Fellowship (SURF) Symposium

Abdominal aortic aneurysms (AAAs), a localized dilation of the vessel wall of 50% or more above normal, claims approximately 14,000 U.S. lives yearly due to aortic rupture. This commonly asymptomatic disease can only be treated by endovascular stent grafts or invasive surgery, usually after the AAA diameter reaches 5 cm. Because these treatment methods carry serious risk, stem cell therapy is being explored in order to provide a low risk option for managing smaller AAAs. To determine if stem cell therapy, once administered, could stabilize or reduce AAA growth, baseline 3D ultrasound measurements in a control group were first needed. …

Estimating Fluid Local Velocity Within A Novel 3d Collagen Matrix Perfusion System, Ana M. Villanueva, Sherry L. Voytik, Kevin P. Buno

The Summer Undergraduate Research Fellowship (SURF) Symposium

Traditional cell culture, performed on flat surfaces under static conditions, does not accurately represent physiologic conditions. As an alternative, groups have applied interstitial fluid flow (0.1-2.0 µm/s) through a 3D cell-embedded extracellular matrix (ECM). Cells sense the flow via mechanotransduction, a process by which cells sense mechanical forces and resultantly respond with biochemical signaling. Previous work demonstrates enhanced cell morphogenesis under interstitial flow conditions. However, fluid flow is poorly described within these systems, stressing the need for a well-characterized 3D interstitial flow system. Understanding fluid mechanics within a perfusion system will help elucidate cellular response to flow-induced mechanical forces.

The …

Tumor-Microenvironment-On-Chip To Mimic Tumor Heterogeneity, Victoria Noe-Kim, Altug Ozcelikkale, Bumsoo Han

The Summer Undergraduate Research Fellowship (SURF) Symposium

Ductal Carcinoma In Situ (DCIS) is a non-invasive cancer that forms around breast milk ducts that can potentially progress into invasive breast cancer if untreated. Lack of models to study its diverse pathophysiology and differential response to treatments poses a challenge to develop standard treatment modalities with improved therapeutic outcomes. The traditional in vitro models such as cell monolayer are convenient but insufficient to represent the physiological characteristics of DCIS tumor microenvironment and often fail to predict clinical outcomes. The animal models effectively simulate the in vivo environment but also lack the ability to control the environmental parameters to match …

Quantification Of Lps Eluate From Coated Microelectrode Devices, Jahrane A. Dale, Janak Gaire, Kevin J. Otto

The Summer Undergraduate Research Fellowship (SURF) Symposium

Penetrating microelectrode arrays have a great potential to be used as control and communication interfaces for neuroprosthetics. A persistent obstacle in the clinical implementation of microelectrode arrays is the chronic degradation of these devices, putatively due to the foreign body response. Though researchers have studied the progression of the foreign body response and the effect of anti-inflammatory drugs on the efficacy of the implant, the exact biological mechanisms of implant degradation are not fully understood. To more closely investigate the effect of the foreign body response on device degradation, neuroinflammation can be exacerbated by coating dummy electrodes implanted into mice …

Nonlinear Optical Microscopy Of Murine Abdominal Aortic Aneurysm, Katherine E. Wilson, Alexa A. Yrineo, Amelia J. Adelsperger, Hilary D. Schroeder, Delong Zhang, Jesse Zhang, Chien-Sheng Liao, Frederick W. Damen, Ji-Xin Cheng, Evan H. Phillips, Craig J. Goergen

The Summer Undergraduate Research Fellowship (SURF) Symposium

Abdominal aortic aneurysm (AAA) is a cardiovascular disease characterized by dilation and weakening of the vessel wall. AAA rupture is responsible for approximately 14,000 deaths annually in the United States [1]. Nonlinear optical (NLO) microscopy presents new possibilities for analyzing AAA tissue samples from murine models. Common NLO techniques are two-photon excitation fluorescence (TPEF), which detects the intrinsic autofluorescent properties of elastin, and second-harmonic generation (SHG), which is specific for collagen fibrils. Elastin and collagen, two major extracellular matrix components, help the aortic wall withstand internal pressure. Murine AAAs were created through 1) subcutaneous continuous systemic infusion of angiotensin II …

Chronic Brain Stimulation Using Micro-Ecog Devices, Hayden C. Carney, Roy Lycke, Kevin J. Otto, Amelia A. Schendel, Justin Williams

The Summer Undergraduate Research Fellowship (SURF) Symposium

Recording and stimulating brain activity has had great success both as a research tool and as a clinical technique. Neural prosthetics can replace limbs, restore hearing, and treat disorders like Parkinson’s and epilepsy, but are relatively crude. Current neural prosthetic systems use penetrating electrodes to achieve high precision, but the invasive nature of these devices provoke a strong immune response that limits chronic use. (Polikov et al) In our study we evaluate micro-electrocortiographic (micro-ECoG) devices which sit under the skull and on the surface of the brain for stimulation over chronic timescales. We anticipate these devices with their less invasive …

Characterization Of Swelling Ratio And Water Content Of Hydrogels For Cartilage Engineering Applications, Emily E. Gill, Renay S.-C. Su, Julie C. Liu

The Summer Undergraduate Research Fellowship (SURF) Symposium

Due to the high prevalence of arthritis and cartilage-related injuries, tissue engineers are studying ways to grow cartilage tissue replacements. Resilin, an elastomeric protein found in insect cuticles, is known for its extraordinary resilience and elasticity. In previous studies, recombinant resilin-based hydrogels, or cross-linked protein networks, exhibited potential for use in cartilage tissue scaffolds. Our lab successfully developed resilin-based proteins with a sequence based on the mosquito gene and showed that resilin-based hydrogels possess mechanical properties of the same order of magnitude as native articular cartilage. In addition, these mechanical properties can be controlled by changing the protein concentration. To …

Design And Fabrication Of A Novel Electrospinning System For Musculoskeletal Tissue Regeneration, Carter L. Chain, Maggie R. Del Ponte, Meng Deng, Feng Yue, Shihuan Kuang

The Summer Undergraduate Research Fellowship (SURF) Symposium

Disease and injury to human tissue, especially musculoskeletal tissue, is a prevalent concern to the public, affecting millions of people each year. Current treatment options involving autografts and allografts are hindered by limited availability and risk of immunogenicity, respectively. In order to overcome these limitations, a transdisiplinary regenerative engineering strategy has emerged with a focus on the development of biomimetic scaffolds that closely mimic the properties of the native tissues. For example, the structure of muscle tissue is characterized by oriented muscle fibers. However, fabrication of aligned nanofiber structures that mimic the anisotropic organization of muscle presents significant engineering challenges. …

Wirelessly Powered And Transmitting Current Sensing Device, Christopher Quinkert, Steven Lee, Pedro Irazoqui

The Summer Undergraduate Research Fellowship (SURF) Symposium

As the rate of incidence of diabetes increases in the modern world, more accurate and reliable methods of glucose detection must be developed for patients with diabetes. Currently, 25.8 million people have diabetes in the United States alone and account for $174 billion in healthcare costs annually [1]. Devices that can be used without the need for as much patient interaction, regular replacement, or great patient expenses would be a large step forward in the ability of doctors and patients to effectively manage diabetes. To measure glucose concentrations in vivo, a biosensor is used to transduce glucose to an electrical …

The Role Of Metal Oxide Layers In The Sensitivity Of Lactate Biosensors Subjected To Oxygen-Limited Conditions, Elizabeth Andreasen, Lia Stanciu, Aytekin Uzunoglu

The Summer Undergraduate Research Fellowship (SURF) Symposium

Amperometric lactate biosensors are used to detect lactate concentration in blood and tissues, which is integral in identifying cyanide poisoning, septic shock, and athletic condition. The construction of lactate biosensors with high sensitivity, selectivity, and stability is imperative to diagnose and determine these medical conditions. Lactate detection is currently limited to oxygen-rich environments due to the fact that oxygen is a limiting factor in the lactate reaction. To circumvent this problem, researchers have developed mediators or alternate, oxygen-free enzymes to improve sensitivity. In our study, ceria (CeO₂) with high oxygen storage capacity (OSC) was introduced to the enzyme …

Real-Time Bio Sensing Using Micro-Channel Encapsulated Mems Resonators, Ayesha Iqbal

Electronic Theses and Dissertations

This work presents a label-free bio-molecular detection technique based on realtime monitoring of the resonant frequency of micromechanical thermal-piezoresistive rotational mode disk resonators encapsulated in microfluidic channels. Mass loading via adsorption of molecular layers on the surface of such devices results in a frequency shift. In order to provide a reliable platform for sample-resonator interactions and to protect the resonators from contaminants, the resonators were encapsulated in PDMS-based microfluidic channels. Micro-channel encapsulation also allows insulation of electrical signals from the analyte solution. To characterize the performance of such devices as real-time label-free bio-molecular detectors, the strong non-covalent binding of Avidin …

Investigating Hemodynamic Responses To Electrical Neurostimulation, Sean Youra

Master's Theses

Since the 1900s, the number of deaths attributable to cardiovascular disease has steadily risen. With the advent of antihypertensive drugs and non-invasive surgical procedures, such as intravascular stenting, these numbers have begun to level off. Despite this trend, the number of patients diagnosed with some form of cardiovascular disease has only increased. By 2030, prevalence of coronary heart disease is expected to increase approximately by 18% in the United States. By 2050, prevalence of peripheral arterial occlusive disease is expected to increase approximately by 98% in the U.S. No single drug or surgical intervention offers a complete solution to these …

A Rubric For Electrochemical Testing Of Metallic Biomaterials, Frederick G. De La Fuente

Master's Theses

Corrosion is a major factor for the failure of metallic medical implants. Testing a metal’s suseptability to corrosion prior to implantation is key to a successful implantation. Electrochemical processes were used in this study to evaluate the characteristics of corrosion of both AISI 316 stainless steel and titanium alloy Ti6Al4V, welded and non-welded. Linear, potentiodynamic, and cyclic polarization curves were produced by the PARC 2273 potentiostat showing the corrosion tendencies of the metals in four unique solutions 3.5% NaCl, 0.35% NaCl, phosphate buffered saline solution (PBS), and Butterfield phosphate buffered solution (BPS). The concentration of chloride ions in solutions affected …

Design, Characterization And Application Of A Multiple Input Stethoscope Apparatus, Spencer Geng Wong

Master's Theses

For this project, the design, implementation, characterization, calibration and possible applications of a multiple transducer stethoscope apparatus were investigated. The multi-transducer sensor array design consists of five standard stethoscope diaphragms mounted to a rigid frame for a-priori knowledge of their relative spatial locations in the x-y plane, with compliant z-direction positioning to ensure good contact and pressure against the subject’s skin for reliable acoustic coupling. When this apparatus is properly placed on the body, it can digitally capture the same important body sounds investigated with standard acoustic stethoscopes; especially heart sounds. Acoustic signal inputs from each diaphragm are converted to …

Improving Golf Putt Performance With Statistical Learning Of Eeg Signals, Qing Guo

Graduate Theses and Dissertations

In this thesis, a machine learning based method is proposed to predict the putt outcomes of golfers based on their electroencephalogram (EEG) data. The method can be used as a core building block of a brain-computer interface, which is designed to provide guidance to golf players based on their EEG patterns. The proposed method includes three steps. First, multi-channel 1-second EEG trials were extracted during golfers' preparation of putting. Second, different features are calculated such as correlation coefficient, power spectrum density and coherence, which are used as features for the classification algorithm. To predict golfers' performance, the support vector machine …

Experimental Terahertz Imaging And Spectroscopy Of Ex-Vivo Breast Cancer Tissue, Tyler C. Bowman

Graduate Theses and Dissertations

This thesis presents experimental results of terahertz imaging and spectroscopy techniques to analyze excised breast cancer tissue. The pulsed terahertz system at the University of Arkansas was used to assess formalin-fixed, paraffin-embedded breast cancer tissue obtained from 22, 40, and 46 year old patients. The tissue for this research was sliced to relatively thin sections of 10 μm thick and mounted on glass slides. Terahertz reflection time and frequency domain images of the breast cancer tissue were then obtained and compared to histopathology slides from the same patient. Results showed good correlation between the reflection images and histopathology slides for …

Cfd Simulation Of The Thermal Performance Of A Parallel Counter-Parallel Flow Heat Exchanger For The Treatment Of Hypothermia, Alex Heller

UNLV Theses, Dissertations, Professional Papers, and Capstones

Hypothermia is a life-threatening condition. Currently, active warming methods are the most effective treatment for dysthermic patients. The aim of this study is to investigate the use of computational fluid dynamics (CFD) in evaluating the thermal performance of a parallel/counter-parallel flow heat exchanger used as part of a fluid warmer to treat Hypothermia. The 3D model of the heat exchanger is divided into three regions; Infusate (fluid to be heated), Hot Water (heating fluid), and a Solid Region (wall). At the end of the heat exchanger, an elbow section is used to create the counter-parallel flow arrangement specific to this …

Impedance Biosensors For The Rapid Detection Of Viral And Bacterial Pathogens Using Avian Influenza Virus Subtypes H5n1 And H7n2 And Escherichia Coli O157:H7 As Model Targets, Jacob David Lum

Graduate Theses and Dissertations

This research investigated impedance biosensors for the rapid detection of viral and bacterial pathogens using avian influenza virus (AIV) subtypes H5N1 and H7N2 and Escherichia coli O157:H7 as the model targets, which were chosen due to their impact on the agricultural and food industries. For the detection of AIV H7N2, a single stranded DNA aptamer was selected using systematic evolution of ligands by exponential enrichment (SELEX). The selected aptamer and a previously selected aptamer against AIV H5N1 were used in a microfluidics chip with an embedded interdigitated array microelectrode to fabricate an impedance biosensor for specific detection of AIV H7N2 …

Microvascular Topology And Intravascular Endothelial Cell Labeling In The Gracilis Anterior Muscle Of Balb/C Mice, Paul Heckler Ii

Biomedical Engineering

Peripheral arterial occlusive disease (PAOD) affects approximately 200 million individuals globally. The major underlying cause of PAOD is an inflammatory disease known as atherosclerosis, which results from the build-up of low-density lipoproteins (LDL) in the sub-intimal space. This initiates a complex cascade of events that lead to plaque growth. Plaque growth can then expand into the lumen of the vessel and result in occlusion and/or thrombosis. Symptoms of the disease can include claudication, ulcers, and/or gangrene, although many patients are asymptomatic. Similar to other forms of ischemic disease, risk factors for PAOD include hypertension, diabetes, and smoking. Common treatments include …

Development Of Poly(Lactic Acid)-Poly(Ethylene Glycol) Nanoparticles For The Delivery Of Non- Toxic Drug In Combination Therapy For The Treatment Of Glioblastoma And Neuroblastoma, Olivia Grace Decroes

All Theses

Glioblastoma and neuroblastoma are both solid-form tumors. Glioblastomas primarily reside in the brain, while neuroblastomas are found in the sympathetic nervous system. Both glioblastoma and neuroblastoma re classified as orphan diseases, which affect less than 200,000 individuals a year. Over the course of 5 years, 40% of patients diagnosed with neuroblastomas and only 6% of patients diagnosed will glioblastomas will be living.^73,74. Glioblastoma and neuroblastoma tumors possess a gene known as MGMT. MGMT is used by tumors as a DNA repair mechanism, which increases the likelihood these tumors will become resistant to traditional drug therapies.^28,37 Other pathways, …

Nerve Fiber Diameter Measurements Using Hematoxylin And Eosin Staining And Brightfield Microscopy To Assess The Novel Method Of Characterizing Peripheral Nerve Fiber Distributions By Group Delay, Jorge Arturo Vazquez

Master's Theses

Peripheral neuropathies are a set of common diseases that affect the peripheral nervous system, causing damage to vital connections between various parts of the body and the brain and spinal cord. Different clinical conditions are known to selectively impact various size nerve fibers, which often makes it difficult to diagnose which peripheral neuropathy a patient might have. The nerve conduction velocity diagnostic test provides clinically useful information in the diagnosis of some peripheral neuropathies. This method is advantageous because it tends to be minimally invasive yet it provides valuable diagnostic information. However, this test does not determine characteristics of peripheral …