Biomedical Engineering and Bioengineering Commons^™

Cardiac Regenerative Medicine: Insights From Healthy And Diseased Engineered Tissues, Pamela Grace Hitscherich

Dissertations

Cardiovascular disease remains the leading cause of mortality in the United States. Current tissue engineering approaches have fallen short of promoting fully functional cardiovascular cells and the post-myocardial infarction microenvironment is still not well understood. These gaps in knowledge are addressed in this dissertation through the development of in vitro engineered cardiac tissues using electroactive materials to enhance the differentiation of pluripotent stem cell derived cardiomyocytes and through the development of in vitro myocardial inflammation models dedicated to understanding cardiomyocytes and macrophages interactions.

Specifically, piezoelectric poly (vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) supports the attachment and survival of mouse embryonic stem cell derived …

Gait Rehabilitation Using Functional Electrical Stimulation Induces Changes In Ankle Muscle Coordination In Stroke Survivors: A Preliminary Study, Jessica L. Allen, Lena H. Ting, Trisha M. Kesar

Faculty & Staff Scholarship

No abstract provided.

Quantifying Mg 2+ Binding To Ssdna Oligomers: A Self-Consistent Field Theory Study At Varying Ionic Strengths And Grafting Densities, Merina Jahan, Mark J. Uline

Faculty Publications

The performance of aptamer-based biosensors is crucially impacted by their interactions with physiological metal ions, which can alter their structures and chemical properties. Therefore, elucidating the nature of these interactions carries the utmost importance in the robust design of highly efficient biosensors. We investigated Mg ²⁺ binding to varying sequences of polymers to capture the effects of ionic strength and grafting density on ion binding and molecular reorganization of the polymer layer. The polymers are modeled as ssDNA aptamers using a self-consistent field theory, which accounts for non-covalent ion binding by integrating experimentally-derived binding constants. Our model captures the typical …

Effect Of Strong Electrolyte Containing Gelling Aids On The Sol-Gel Transition Temperature Of Hypromellose 2910, Elnaz Sadeghi

Biomedical Engineering ETDs

Hypromellose, or hydroxypropyl methylcellulose (HPMC) - has been widely used for biomedical and pharmaceutical applications due to its advantages, including that it is modifiable in terms of viscosity, and it has the ability to form thermally reversible hydrogels. The thermal gelation temperature (T_Gel) of a given HPMC solution strongly depends on its characteristic grade and the solution concentration. Applying certain additives can modify the T_Gel even further; depending on their nature and concentration. With the addition of said additives, a lower or higher T_Gel can be obtained. For example, the addition of sodium chloride (NaCl) reduces …

Kcnq1/Kcne1 Interaction In The Cardiac Iks Channel And Its Physiological Consequences, Jiajing Xu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Dynamic conformational changes of ion channel proteins during activation gating determine their function as carriers of current. The relationship between these molecular movements and channel function over the physiological timescale of the action potential (AP) has not been fully established due to limitations of existing techniques. We constructed a library of possible cardiac IKs protein conformations and applied a combination of protein segmentation and energy linearization to study this relationship computationally. Simulations reproduced the effects of the beta-subunit (KCNE1) on the alpha-subunit (KCNQ1) dynamics and function, observed in experiments. Mechanistically, KCNE1 increased the probability of “visiting” conducting pore conformations on …

Investigating Cyanobacteria Metabolism And Channeling-Based Regulations Via Isotopic Nonstationary Labeling And Metabolomic Analyses, Mary Helen Abernathy

McKelvey School of Engineering Graduate Student Theses & Dissertations

Cyanobacteria have the potential to be low-cost and sustainable cell factories for bio-products; however, many challenges face cyanobacteria as biorefineries. This dissertation seeks to advance non-model photosynthetic organisms for biotechnology applications by characterizing central carbon metabolism and its regulations. Cyanobacteria phenotypes for bio-production are examined and their intracellular metabolism is quantified. Using isotopic labeling experiments, phenotypic relationships between biomass composition, central carbon fluxes, and metabolite pool sizes are investigated. Metabolic analyses of cyanobacteria led to new investigations of flux regulation mechanisms via protein spatial organizations or metabolite channeling. Metabolite channeling is further explored as a hypothesis to explain enigmatic labeling …

Molecular Basis Of Class Ib Drug Interactions With The Nav Channel Macromolecular Complex: A Route To Personalized Medicine For Cardiac Arrhythmia, Wandi Zhu

McKelvey School of Engineering Graduate Student Theses & Dissertations

The heart rhythm is precisely controlled by the electrical impulse that propagate in the cardiac tissue. In single cardiomyocytes, the electrical activity generated by action potentials (AP). Cardiac NaV channels (NaV1.5) carry a large influx of Na+ that mediates the initiation and propagation of the AP in both atria and ventricles. Disruption of NaV1.5 function by genetic variants or external factors can result in deadly arrhythmias, such as long QT syndrome and Brugada syndrome. Thus, NaV channels are import therapeutic targets. The class I antiarrhythmics are the modulators of the NaV channels. Although they have been used clinically for over …

Basis Vector Model Method For Proton Stopping Power Estimation Using Dual-Energy Computed Tomography, Shuangyue Zhang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Accurate estimation of the proton stopping power ratio (SPR) is important for treatment planning and dose prediction for proton beam therapy. The state-of-the-art clinical practice for estimating patient-specific SPR distributions is the stoichiometric calibration method using single-energy computed tomography (SECT) images, which in principle may introduce large intrinsic uncertainties into estimation results. One major factor that limits the performance of SECT-based methods is the Hounsfield unit (HU) degeneracy in the presence of tissue composition variations. Dual-energy computed tomography (DECT) has shown the potential of reducing uncertainties in proton SPR prediction via scanning the patient with two different source energy spectra. …

Biodegradable And Biocompatible Silk Fibroin For Optical Applications, Corey Bryce Malinowski

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study presents nanopatterned silk fibroin films that were fabricated using soft lithography and nanoimprinting to replicate patterns from diffraction gratings. These film’s optics were analyzed based on their light scattering potential as well as their transmittance and transmission haze using a laser light, spectrometer, and UV-Vis spectrophotometer, respectively. The patterned fibroin films all displayed similar light scattering patterns to their master patterns with some transmission haze. When using the spectrometer to measure samples, those made without any nanostructure displayed transmission of 90% and over, while those with patterns depended on the structure used. The denser a structure, like the …

Chemically Modified Monolayer Surfaces Influence Valvular Interstitial Cell Attachment And Differentiation For Heart Valve Tissue Engineering, Matthew N. Rush

Nanoscience and Microsystems ETDs

As a cell mediated-process, valvular heart disease (VHD) results in significant morbidity and mortality world-wide. In the US alone, valvular heart disease VHD is estimated to affect 2.5% of the population with a disproportionate impact on an increasing elderly populous. It is well understood that the primary driver for valvular calcification is the differentiation of valvular interstitial cells (VICs) into an osteoblastic-like phenotype. However, the factors leading to the onset of osteoblastic-like VICs (obVICs) and resulting calcification are not fully understood and a more complete characterization of VIC differentiation and phenotypic change is required before treatment of valve disease or …

Towards An In Vitro Model Of Testing Osteoblast Cellular Function In Contact With Various Surfaces, Raheleh Miralami

Theses & Dissertations

Past studies have shown that the success of total joint replacements depends on the biocompatibility of orthopaedic materials, which can be improved by modifying the implant surface. However, the exact roles of these modifications and their effective mechanisms are poorly understood. The objective of this study was to develop and evaluate a model system to investigate the impact of nano-structured surfaces, produced by the ion beam-assisted deposition (IBAD) technique, on biomarkers of osteointegration using an in vitro model. The IBAD technique was employed to deposit zirconium oxide (ZrO₂), Titanium oxide (TiO₂), and Titanium (Ti) nano-films on …

Manganese-Enhanced Magnetic Resonance Imaging: Overview And Central Nervous System Applications With A Focus On Neurodegeneration, Ryan A. Cloyd, Shon A. Koren, Jose F. Abisambra

Physiology Faculty Publications

Manganese-enhanced magnetic resonance imaging (MEMRI) rose to prominence in the 1990s as a sensitive approach to high contrast imaging. Following the discovery of manganese conductance through calcium-permeable channels, MEMRI applications expanded to include functional imaging in the central nervous system (CNS) and other body systems. MEMRI has since been employed in the investigation of physiology in many animal models and in humans. Here, we review historical perspectives that follow the evolution of applied MRI research into MEMRI with particular focus on its potential toxicity. Furthermore, we discuss the more current in vivo investigative uses of MEMRI in CNS investigations and …

Analysis Of Coherence Between Electromyographic (Emg) Signals To Examine Neural Correlations In Muscular Activation During Standing Balance Tasks: A Pilot Study, Anuj Ojha

Masters Projects

The motor coordination of the muscles is controlled by the Central Nervous System (CNS), but the precise neural mechanisms for the CNS coordinating the muscles are not completely understood. The purpose of my study was to find the EMG-EMG coherence in different neural frequency bands to examine the neural correlations during muscle activation. EMG signal was recorded from six different healthy young subjects. The EMG signal with sampling frequency fs=1200 Hz was collected for 30 seconds (t=30 sec) from three different muscles on both legs: - tibialis anterior, medial gastrocnemius and soleus. The data were collected for the following four …

Assessing Biofiltration Without Ozonation For Removal Of Trihalomethane Precursors In Drinking Water At The Beaver Water District Drinking Water Treatment Plant, Sana Ajaz

Graduate Theses and Dissertations

Biofiltration without pre-ozonation has the capability to remove natural organic matter (NOM) fractions that serve as precursors of disinfection byproducts (DBPs), which include the four regulated trihalomethanes (THMs) and dichloroacetonitrile (DCAN). Rapid small-scale column tests (RSSCTs) and Pilot Plant filters operated at empty-bed contact times (EBCTs) of 4, 8, and 16 minutes were used to evaluate the performance of nutrient-amended (free ammonia and phosphorus) biofiltration for THM and DCAN precursor removal, as measured using formation potential (FP) tests. NOM surrogates – which include dissolved organic carbon (DOC), specific ultraviolet absorbance (SUVA254) and fluorescence-PARAFAC components – were measured weekly throughout the …

Rational Design And Synthesis Of Biodegradable Polyurethane Based Biomaterials, Cancan Xu

Bioengineering Dissertations - Archive

Biodegradable polyurethanes have been applied in biomedical field since 1960s. In recent years, biodegradable polyurethanes have been widely investigated for tissue repair and regeneration because of their good mechanical properties, elasticity, biodegradability, biocompatibility and processability. Compared with some commonly used biodegradable polymers, such as poly(glycolide) (PGA), poly(lactide) (PLA), poly(ε-caprolactone) (PCL) and polyhydroxyalkanoates (PHA), the favorable aspects of biodegradable polyurethane are its mechanical, physicochemical and biological properties can be tailored by varying the three blocks in polyurethane backbone, diisocyanate, diol and chain extender. In this thesis, we focus on the development of different functional biodegradable polyurethanes to study their structure-property relationships …

Stimuli-Responsive Nanoparticles For Treatment Of Lung Cancer, Roshni Iyer

Bioengineering Dissertations - Archive

Despite extensive research and progress in anti-cancer therapeutics, an effective treatment for non-small cell lung cancer (NSCLC) remains elusive, resulting in poor 5-year patient survival rate. Towards this end, we have explored a therapeutic regimen to improve the effects of local concurrent chemo-radiation-therapy (CRT), by utilizing multifunctional stimuli-responsive nanoparticles (NPs) as drug carriers. We have also utilized lung cancer targeting strategies for site-specific drug delivery, mainly antibodies against the Ephrin-transmembrane receptor kinase (EphA2), that is over-expressed mainly on lung cancer cells, to promote the targeted delivery of drugs to only cancer cells, and eventually reduce the toxicity to healthy tissues. …

Development Of Particle Platforms For Delivery Of Angiogenic Reagents To Treat Peripheral Arterial Diseases, Duong Quang Le

Bioengineering Dissertations - Archive

Peripheral arterial disease (PAD) is a disease that one or several peripheral arteries are narrowed or blocked. PAD is an emerging disease that cost annually 10-20 billions of US dollars for health care in America. PAD patients suffer high risk of limb loss, amputations and mortalities. At 5 years, the amputation rate for PAD is 40%-70% while the 5-year survival rate is less than 30%. For PAD patients undergoing acute and critical limb ischemia, surgery bypass and endovascular balloon/stenting are applied as standard treatments. However, surgical bypass is subject to patients’ readiness of autologous veins and the depth of arteries …

Preparation Of Dual Fluorescence Agents-Loaded Nanoparticle And Its In Vitro And In Vivo Application, Hong-Hao Thi Vu

Bioengineering Theses - Archive

There’re many existing imaging tools that composed of different imaging moieties to improve both resolution and sensitivity, however there’s not yet any imaging method that could be effectively utilized in both in vitro and in vivo study. To fill the gap, dual dyes-labeling fluorescent imaging nanoprobes was synthesized to simultaneous carry both visible fluorescent isothiocyanate (FITC) dye and near infra red (NIR) dye, 1,1′,3,3,3′,3′- hexamethylindotricarbocyanine iodide dye agent (HITC). For that, nanoparticles (NPs) was synthesized from 2-Hydroxyethyl methacrylate, styrene, acrylic acid and fluorescein-o-acrylate which contains visible FITC dye. The NPs were then labeled with HITC dye via physical entrapment to …

Identification And Engineering Of Nonribosomal Peptide Biosynthetic Systems, Fuchao Xu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research focuses on the understanding and engineering of nonribosomal peptide biosynthetic pathways in Streptomyces coelicolor CH999, Escherichia coli BAP1 and Saccharomyces cerevisiae BJ5464-NpgA. The biosynthetic systems of indigoidine from bacteria and beauvericin/bassianolide from fungi were studied in this research. The production of these valuble products was significantly increased by enhancing their synthetic pathway with metabolic engineering approaches.

Indigoidine is a bacterial natural product with antioxidant and antimicrobial activities. Its bright blue color resembles the industrial dye indigo, thus representing a new natural blue dye that may find uses in industry. Indigo is a dark blue crystalline powder and has …

Hip And Knee Biomechanics For Transtibial Amputees In Gait, Cycling, And Elliptical Training, Greg Orekhov

Master's Theses

Transtibial amputees are at increased risk of contralateral hip and knee joint osteoarthritis, likely due to abnormal biomechanics. Biomechanical challenges exist for transtibial amputees in gait and cycling; particularly, asymmetry in ground/pedal reaction forces and joint kinetics is well documented and state-of-the-art passive and powered prostheses do not fully restore natural biomechanics. Elliptical training has not been studied as a potential exercise for rehabilitation, nor have any studies been published that compare joint kinematics and kinetics and ground/pedal reaction forces for the same group of transtibial amputees in gait, cycling, and elliptical training. The hypothesis was that hip and knee …

Il-12 Gene Electrotransfer Triggers A Change In Immune Response Within Mouse Tumors, Guilan Shi, Chelsea Edelblute, Sezgi Arpag, Cathryn Lundberg, Richard Heller

Bioelectrics Publications

Metastatic melanoma is an aggressive skin cancer with a relatively low survival rate. Immune-based therapies have shown promise in the treatment of melanoma, but overall complete response rates are still low. Previous studies have demonstrated the potential of plasmid IL-12 (pIL-12) delivered by gene electrotransfer (GET) to be an effective immunotherapy for melanoma. However, events occurring in the tumor microenvironment following delivery have not been delineated. Therefore, utilizing a B16F10 mouse melanoma model, we evaluated changes in the tumor microenvironment following delivery of pIL-12 using different GET parameters or injection of plasmid alone. The results revealed a unique immune cell …

Automated Quantification And Evaluation Of Motion Artifact On Coronary Ct Angiography Images, Hongfeng Ma, Eric Gros, Scott G. Baginski, Zachary R. Laste, Naveen M. Kulkarni, Darin Okerlund, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

Abstract

Purpose

This study developed and validated a Motion Artifact Quantification algorithm to automatically quantify the severity of motion artifacts on coronary computed tomography angiography (CCTA) images. The algorithm was then used to develop a Motion IQ Decision method to automatically identify whether a CCTA dataset is of sufficient diagnostic image quality or requires further correction.

Method

The developed Motion Artifact Quantification algorithm includes steps to identify the right coronary artery (RCA) regions of interest (ROIs), segment vessel and shading artifacts, and to calculate the motion artifact score (MAS) metric. The segmentation algorithms were verified against ground‐truth manual segmentations. The …

Wireless Ekg, James Kerman, Chin Chao, Galen Wu, Eric Burstedt

Mechanical Engineering

In 2016, Dr. Ahmad Nooristani identified a need for a personal EKG that is cheaper and simpler than hospital grade systems, but more accurate than personal devices currently on the market. Two previous teams did significant background research, prototyping, focusing on ease of use, portability, and physical specifications. However, neither team was able to produce a device with electrodes that could successfully collect an EKG signal and transmit it to a phone or tablet, one of the main requirements from the Dr. Nooristani. This team focused on designing a six lead, five electrode EKG device to transmit EKG data from …

Superelastic And Ph-Responsive Degradable Dendrimer Cryogels Prepared By Cryo-Aza-Michael Addition Reaction, Juan Wang, Hu Yang

Chemical and Biochemical Engineering Faculty Research & Creative Works

Dendrimers exhibit super atomistic features by virtue of their well-defined discrete quantized nanoscale structures. Here, we show that hyperbranched amine-terminated polyamidoamine (PAMAM) dendrimer G4.0 reacts with linear polyethylene glycol (PEG) diacrylate (575 g/mol) via the aza-Michael addition reaction at a subzero temperature (-20 °C), namely cryo-aza-Michael addition, to form a macroporous superelastic network, i.e., dendrimer cryogel. Dendrimer cryogels exhibit biologically relevant Young's modulus, high compression elasticity and super resilience at ambient temperature. Furthermore, the dendrimer cryogels exhibit excellent rebound performance and do not show significant stress relaxation under cyclic deformation over a wide temperature range (-80 to 100 °C). The …

Chemically Active Rheological Modifiers For The Improved Clinical Use Of Cyanoacrylates, Kyle Joseph Garcia

All Dissertations

Over 100 million surgical incisions, 50 million traumatic wounds, and 20 million minor lacerations from cuts and grazes are treated globally each year. One study determined that globally internal and external wounds occur for 40% and 37% of cases respectively for a total of 111 million patients that were treated for wounds. The remaining 23% of patients were treated for minor lacerations and trauma in the emergency room. These wounds require immediate medical attention including pressure application, sutures, clips, tissue cautery, and/or topical hemostatic agents to cease hemorrhage or the exit of other bodily fluids. With blood flow ceased, wound …

Modeling And Simulation Methodologies For Spinal Cord Stimulation., Saliya Kumara Kirigeeganage

Electronic Theses and Dissertations

The use of neural prostheses to improve health of paraplegics has been a prime interest of neuroscientists over the last few decades. Scientists have performed experiments with spinal cord stimulation (SCS) to enable voluntary motor function of paralyzed patients. However, the experimentation on the human spinal cord is not a trivial task. Therefore, modeling and simulation techniques play a significant role in understanding the underlying concepts and mechanics of the spinal cord stimulation. In this work, simulation and modeling techniques related to spinal cord stimulation were investigated. The initial work was intended to visualize the electric field distribution patterns in …

Acetylation Profiles Of Histone And Non-Histone Proteins In Breast Cancer, Alla Karpova

McKelvey School of Engineering Graduate Student Theses & Dissertations

This study evaluates the impact of protein acetylation on breast cancer gene expression and the regulation of metabolism. Acetylation is the second abundant post-translational modification after phosphorylation, regulating protein activity and function. The alterations in acetylation of both histone and non-histone proteins is known to be related to many human diseases, including cancer. Acetylation and deacetylation of histones is closely associated with the regulation of gene expression, while acetylation of non-histone proteins may have a broad effect on major cellular processes, such as proliferation, metabolism, cell cycle and apoptosis, imbalanced regulation of which is essential for cancer development. Therefore, it’s …

Impedance Sensing Of Cancer Cells Directly On Sensory Bioscaffolds Of Bioceramics Nanofibers, Hanan Alismail

Graduate Theses and Dissertations

Cancer cell research has been growing for decades. In the field of cancer pathology, there is an increasing and long-unmet need to develop a new technology for low-cost, rapid, sensitive, selective, label-free (i.e. direct), simple and reliable screening, diagnosis, and monitoring of live cancer and normal cells in same shape and size from the same anatomic region. For the first time on using an impedance signal, the breast cancer and normal cells have been thus screened, diagnosed and monitored on a smart bioscaffold of entangled nanowires of bioceramics titanate grown directly on the surface of implantable Ti-metal and characterized by …

Numerical Simulation And Optimization Of Blalock-Taussig Shunt, Thomas Hess, Ramesh K. Agarwal

McKelvey School of Engineering Graduate Student Theses & Dissertations

The goal of this study is to create an optimized Blalock-Taussig shunt used to temporarily repair pulmonary vascular blockages allowing a child time to grow so a more permanent surgical repair of the heart and vasculature can be performed. Blalock-Taussig or BT shunts are a surgical procedure performed on infants suffering from cyanosis or “Blue Baby Syndrome.” A BT shunt is an artificial vessel placed between the right ventricle and the pulmonary artery to increase blood flow in the lung and blood oxygen saturation levels. In a study of 96 patients with currently in use modified BT shunts, 32 patients …

Morphological Features Of Dysplastic Progression In Epithelium: Quantification Of Cytological, Microendoscopic, And Second Harmonic Generation Images, Sandra Patricia Gordon

Graduate Theses and Dissertations

Advances in imaging technology have led to a variety of available clinical and investigational systems. In this collection of studies, we tested the relevance of morphological image feature quantification on several imaging systems and epithelial tissues. Quantification carries the benefit of creating numerical baselines and thresholds of healthy and abnormal tissues, to potentially aid clinicians in determining a diagnosis, as well as providing researchers with standardized, unbiased results for future dissemination and comparison.

Morphological image features in proflavine stained oral cells were compared qualitatively to traditional Giemsa stained cells, and then we quantified the nuclear to cytoplasm ratio. We determined …