Biomedical Engineering and Bioengineering Commons^™

Pulsed Electric Fields Sensitize Methicillin-Resistant Staphylococcus Aureus To Antibacterial Therapies And Stimulate Host Immune Responses, Alexandra E. Chittams-Miles

Biomedical Sciences Theses & Dissertations

This research explores the impact of nanosecond pulsed electric fields (nsPEF) on two fronts: their immune stimulatory effects and their potential as a novel strategy to enhance the sensitivity of Methicillin-resistant Staphylococcus aureus (MRSA) to clinically relevant antibiotics. While pulsed electric fields have been reported to have an immune stimulatory effect, the mechanisms responsible for these effects have yet to be determined.

Our investigation addresses the rising concern of MRSA derived skin and soft tissue infections (SSTIs). Consistent with other publications, we found that nsPEF alone cause modest inactivation of planktonic MRSA. We then investigated the effects of nsPEF in …

Engineered Exosomes For The Multimodal Imaging Directed Photo-Immunotherapy Of Colorectal Cancer, Deepak S. Chauhan, Meena Jaggi, Subhash C. Chauhan, Murali M. Yallapu

Research Symposium

Background: Rio Grande Valley experience severe cancer health disparity. A novel therapeutic modality may serve as better therapeutic option. Nanohybrids endowed with multifunctionality, longer circulation time, large surface area have emerged as an active preference for cancer research. However, rising concern of nanomaterials toxicity and scalability issues has slowed their translation to clinics. Exosomes (Exo) are endogenous endocytic origin 40-100 nm vesicles found in various body fluids, which in comparison to synthetic nanoparticles, are biodegradable, highly biocompatible as well as immunocompatible in nature. Although bulk isolation of exosomes from human body fluids is still a problem and engineering of exosomes …

Analyzing Pseudomonas Aeruginosa With Bacteriophage Tags Using Photoacoustic Flow Cytometry, Jennifer C. Schinke

Electronic Theses and Dissertations

The number of daily bacterial infections is climbing and the CDC explains that this is due to the antibiotic-resistant threat in the United States. Finding a faster way of bacterial identification is necessary as it currently takes 1-4 days for a medical lab to culture and identify bacteria. Photoacoustic flow cytometry (PAFC) can be used as an alternative method resulting in swift identification within an hour (Edgar, 2019). Pseudomonas aeruginosa, cell line PA01, will be coated in up to a few hundred red dyed phages making it detectible by the photoacoustic flow cytometry system. Bacteriophages (phages) are viruses that …

Photodynamic Therapy To Treat Triple Negative Breast Cancer In Vitro, Hunter S. Warren

All Theses

Triple negative breast cancer (TNBC) is the most resilient form of breast cancer, being one of the leading causes of death for women and making up 7% of all cancer deaths. Photodynamic therapy (PDT) offers a minimally invasive solution to TNBC as a passive-targeting treatment that reduces the need for other well established yet harsh treatments that can be taxing on the patient. PDT involves the use of a high-energy red light on the area of a tumor injected with photosensitizers (PS) that generate reactive oxygen species (ROS) in the tumor, triggering cell death. The PS tetra(hydroxyphenyl)chlorin (m-THPC) was used …

Comparison Of In-Vitro 3d Human Embryoids With Current Models For Gastrulation, Jin Park

McKelvey School of Engineering Theses & Dissertations

Gastrulation is an early morphogenetic process that is conserved across most metazoans and lays out the future body plan through the formation and shaping of the three germ layers: endoderm, mesoderm, and ectoderm. Despite its importance, not much is known about the events surrounding human gastrulation that occurs in utero due to ethical and technical limitations on studying human embryos. Therefore, many researchers have devised protocols for creating in vitro models of gastrulation using embryonic stem cells. Initially starting with mouse embryonic stem cells, the field of in vitro embryo models has advanced rapidly, with protocols using human embryonic stem …

Identification Of Proteins Involved In Cell Membrane Permeabilization By Nanosecond Electric Pulses (Nsep), Giedre Silkuniene, Uma Mangalanathan, Alessandra Rossi, Peter A. Mollica, Andrei G. Pakhomov, Olga N. Pakhomova

Bioelectrics Publications

The study was aimed at identifying endogenous proteins which assist or impede the permeabilized state in the cell membrane disrupted by nsEP (20 or 40 pulses, 300 ns width, 7 kV/cm). We employed a LentiArray CRISPR library to generate knockouts (KOs) of 316 genes encoding for membrane proteins in U937 human monocytes stably expressing Cas9 nuclease. The extent of membrane permeabilization by nsEP was measured by the uptake of Yo-Pro-1 (YP) dye and compared to sham-exposed KOs and control cells transduced with a non-targeting (scrambled) gRNA. Only two KOs, for SCNN1A and CLCA1 genes, showed a statistically significant reduction in …

Producing And Measuring Oscillatory Shear In A Novel Microfluidic Chip, Sanaz Lordfard, Daniel Lorusso, Tamie L. Poepping, Hristo N Nikolov, Kayla Soon, Stephen Sims, Jeffrey Dixon, David Holdsworth

Undergraduate Student Research Internships Conference

Purpose: To demonstrate the effectiveness of a novel microfluidic device mimicking oscillatory blood flow, allowing cell biologists to examine how endothelial cells respond to a range of oscillatory shear stress levels.

Methods: The microfluidic chip consists of a circular-shaped reservoir, leading to a rectangular channel that is examined under a microscope. The plunger is connected to a speaker system and oscilloscope, allowing the plunger to apply a range of frequencies (5-60Hz) and voltages (5-10 V, leading to a variety in oscillation amplitudes) to the reservoir region. 1.1 um fluorescent particles diluted in distilled water were used for tracking. Processing was …

Engineering Of Ideal Systems For The Study And Direction Of Stem Cell Asymmetrical Division And Fate Determination, Martina Zamponi

Biomedical Engineering Theses & Dissertations

The cellular microenvironment varies significantly across tissues, and it is constituted by both resident cells and the macromolecules they are exposed to. Cues that the cells receive from the microenvironment, as well as the signaling transmitted to it, affect their physiology and behavior. This notion is valid in the context of stem cells, which are susceptible to biochemical and biomechanical signaling exchanged with the microenvironment, and which plays a fundamental role in establishing fate determination and cell differentiation events. The definition of the molecular mechanisms that drive stem cell asymmetrical division, and how these are modulated by microenvironmental signaling, is …

Development Of A Long-Read Sequencing Protocol To Assess The Precision And Efficacy Of Gene Editing For Duchenne Muscular Dystrophy, Landon Andrew Burcham

Graduate Theses and Dissertations

This work establishes a method for assessing on-target precision due to CRISPR-Cas9 gene editing, especially within the context of exon skipping therapy for Duchenne Muscular Dystrophy. The proposed method utilizes an Oxford nanopore long-read sequencing approach to sequence amplified regions of DNA that have been edited using CRISPR-Cas9. NIH3T3 and C2C12 cell lines were treated with a dual-guide CRISPR-Cas9 system, that targets and deletes exon 23 from the DMD gene in mouse samples. Deletion PCR revealed deletion of exon 23 in both DNA and cDNA samples. Additionally, sequencing using Oxford Nanopore revealed targeted exon 23 deletion as the most prevalent …

Investigating The Impact Of Hypoxia On Reactive Oxygen Species Generation Within Murine Breast Cancer Cells, Jared Mcpeake

Biomedical Engineering Undergraduate Honors Theses

When cancer metastasizes from a primary tumor site to secondary site through the bloodstream or lymph, the cancer becomes more difficult to treat. For this reason, it is vital to study what indicates the metastatic potential of a tumor. Current research has shown that cell lines with high metastatic potential display increased levels of metabolic adaptability over their nonmetastatic counterparts after undergoing hypoxic conditions. One method of assessing this adaptability is to measure the concentration of reactive oxygen species (ROS) produced by the cells while undergoing oxidative stress. In highly adaptable metastatic cells, an increase of ROS buildup within the …

Breaks In Longitudinal Elastic Fibers Of Human Femoropopliteal Arteries, Elham Zamani

UNO Student Research and Creative Activity Fair

Breaks in Longitudinal Elastic Fibers of Human Femoropopliteal Arteries

Elham Zamani1, Majid Jadidi1

1 Department of Biomechanics, University of Nebraska Omaha, Omaha, NE

Introduction: Elastin is a major protein in the body with half-life >50 years. It is thought that elastic fibers are formed before the postnatal period. In the femoropopliteal artery (FPA), the main artery in the leg, longitudinal elastic fibers are present in External Elastic Lamina (EEL). Our team has studied more than 1000 cadaveric human FPA and has noticed that there are big breaks in their longitudinal elastic fibers in some subjects. Our goal in this work …

An Antimicrobial Polydopamine Surface Coating To Reduce Biofouling On Telemetry Tags Used In Marine Conservation Practices, Ariana Smies

Dissertations, Master's Theses and Master's Reports

Satellite telemetry tags are used to track the migration patterns of large cetaceans. These tags penetrate the dermis and remain embedded in the underlying blubber tissue. As the dermis of cetaceans is host to a diverse microbiome, and it is impossible to clean the skin before implanting the devices, the potential for infection is increased when the tags penetrate through the skin. H₂O₂ is a potential antimicrobial agent that, in addition to showing broad-spectrum efficacy against gram-negative and gram-positive bacteria, can promote wound healing outcomes by promoting proliferative factors and peptides that protect against oxidative stress. However, …

Novel Approaches For Enhancing Cell Survival And Function In Vivo, Ou Wang

Department of Chemical and Biomolecular Engineering: Theses and Student Research

FDA has approved several cell-based therapeutics and hundreds of cell therapy clinical trials are ongoing. Cells will be a significant type of medicine after small molecule and protein drugs. However, several obstacles need to be addressed to achieve the widespread use of cellular therapeutics. The first challenge is the low efficacy of cell transplantation due to low retention, survival, integration, and function of cells in vivo. The second challenge is producing a massive number of cells for clinical treatment with cost-effectively and reproducibly technologies.

In this thesis, we proposed and investigated two approaches to address these challenges. To begin …

Investigating Effects Of Microenvironmental Stress On Cell Metabolism Using Multiphoton Imaging, Lisa Rebello

Graduate Theses and Dissertations

Resistance to therapy in cancer is a major cause of poor prognosis in patients. Tumor hypoxia plays an active role in mediating treatment resistance and has been linked to metastases and metastatic potential in cancer. Our research focused on three objectives: i) To understand metabolic effects of chronic and intermittent hypoxia in murine breast cancer cells and its affiliation with metastatic potential ii) To identify the metabolic changes associated with radiation therapy in a panel of radiosensitive and radioresistant human head and neck cancer cells and iii) to monitor the changes in cell metabolism associated with gain of treatment resistance. …

Human Ipsc Tissue-Engineered Cartilage For Disease Modeling Of Skeletal Dysplasia-Causing Trpv4 Mutations, Amanda R. Dicks

McKelvey School of Engineering Theses & Dissertations

Cartilage is essential to joint development and function. However, there is a variety of cartilage diseases, ranging from developmental (e.g., skeletal dysplasias) to degenerative (e.g., arthritis), in which treatments and therapeutics are lacking. For example, specific point mutations in the ion channel transient receptor potential vanilloid 4 (TRPV4) prevent proper joint development, leading to mild brachyolmia and severe, neonatally lethal metatropic dysplasia. Tissue-engineered cartilage offers an opportunity to elucidate the underlying mechanisms of these cartilage diseases for the development of treatments. Human induced pluripotent stem cells (hiPSCs) are an improved cell source option for cartilage tissue engineering given their minimal …

Synthetic Gene Circuits For Self-Regulating And Temporal Delivery Of Anti-Inflammatory Biologic Drugs In Engineered Tissues, Lara Pferdehirt

McKelvey School of Engineering Theses & Dissertations

The recent advances in the fields of synthetic biology and genome engineering open up new possibilities for creating cell-based therapies. We combined these tools to target repair of articular cartilage, a tissue that lacks a natural ability to regenerate, in the presence of arthritic diseases. To this end, we developed cell-based therapies that harness disease pathways and the unique properties of articular cartilage for prescribed, localized, and controlled delivery of biologics, creating the next generation of cell therapies and new classes of synthetic circuits. We created tissue engineered cartilage from murine induced pluripotent stem cells that had the ability to …

Impact Of Angiogenic And Osteogenic Factors In The Presence Of Biodegradable Piezoelectric Films, Jayla Millender

University Scholar Projects

One of the most common causes of bone graft rejection is lack of a vascular network connecting the graft to the existing native tissue – allowing for nutrient flow. Under current grafting techniques, the existing blood vessel network in the patient slowly invades the implant in order to supply the injured site with its necessary nutrients. The purpose of this research is to determine if a synthetic bone graft with a stable microvascular network can be developed in vitro. I hypothesize that the use of indirect angiogenic factors such as sonic hedgehog homolog and hypoxia-inducible factor-1 in combination with the …

Involvement Of The Ino80 Chromatin Remodeling Complex In Cell Division And Genomic Stability, Ethan Chen

Biomedical Engineering Undergraduate Honors Theses

Cell division is a vital biological process for growth and development in both single and multi-cellular organisms—whereby the cell must duplicate its organelles and genome in entirety and appropriately distribute the copied contents to the daughter cells. Cells undergo a cycle of two distinct phases: interphase and mitosis. During interphase, the cell replicates its genomic DNA (in the form of chromosomes) located within the nucleus. DNA replication is carried out in a euchromatin state, where the chromosome structure is loose and easily accessible by DNA polymerase and other replication enzymes. Upon the completion of replication, chromatin is condensed into highly …

Biomedical Applications And Syntheses Of Selected Anthraquinone Dyes, Richard Sirard

Senior Honors Theses

Anthraquinones are aromatic organic compounds that have multiple applications in the biomedical field. Some anthraquinone-based compounds are used as fluorophores to contrast cell nuclei while others act as chemotherapeutic agents. However, there are not many fluorescent anthraquinone cell stains currently available. In this study, commercially available anthraquinone dyes, in addition to other dye families and compounds, were reviewed for their unique properties, advantages, and drawbacks. The development and characterization of three novel anthraquinone fluorophores revealed promising photophysical characteristics, like large Stokes shifts. One of the compounds, RBS3, was chosen for fixed and live cell staining and exhibited desirable biomedical properties. …

Trials And Tribulations Of Humanizing Mice For Cancer Research, Brittney Ruedlinger, Steven Warsof, Eric Feliberti, Mary Beth Hughes, Ayobami ‘Edwin’ Oshin, Chunqi Jiang, Brittany P. Lassiter, Siqi Guo, Stephen J. Beebe

The Graduate School Posters

Cancers are aggressive, evasive, and ruthless killers, claiming millions of lives every year. Cancers are heterogeneous and there is often no single, clearly defined problem as they harness and manipulate a multitude of fundamental mechanisms at the very essence of life. To investigate these mechanisms and vet potential interventive therapies, humanized mice offer a unique model as a prelude to the use of nanosecond pulse stimulation (NPS), a pulse power technology applying nanosecond duration, high electric field pulses, to ablate human tumors. Immunodeficient mouse strains, NSG and NSG-SGM3, were engrafted with human immune cells and human tumors, which would allow …

Cyclophilin D Is A Sensor Of Nano-Pulse Stimulation, Brittney Ruedlinger, Bani Hani Maisoun, Lucas Potter, Nicola Lai, Stephen J. Beebe

The Graduate School Posters

Nano-Pulse Stimulation (NPS), a pulsed power-derived technology, stimulates structural and functional changes in plasma membranes and cellular organelles. NPS induces a Ca²⁺ influx and opening of the mitochondrial permeability transition pore (mPTP) that dissipates the mitochondrial membrane potential (ΔΨ_m) and, when sustained, induces regulated cell death. Here we show that in rat cardiomyoblasts (H9C2) cyclophilin D (CypD) is a mitochondrial sensor for NPS as defined by observations that loss of ΔΨ_m is Ca²⁺ and mitochondrial reactive oxygen species (mROS) dependent and cyclosporin A (CsA)-sensitive, which are diagnostic qualities for effects on CypD and the mPTP. …

In Vivo Optical Metabolic Imaging Of Long-Chain Fatty Acid Uptake In Orthotopic Models Of Triple-Negative Breast Cancer, Megan C. Madonna, Joy E. Duer, Joyce V. Lee, Jeremy Williams, Baris Avsaroglu, Caigang Zhu, Riley Deutsch, Roujia Wang, Brian T. Crouch, Matthew D. Hirschey, Andrei Goga, Nirmala Ramanujam

Biomedical Engineering Faculty Publications

Targeting a tumor’s metabolic dependencies is a clinically actionable therapeutic approach; however, identifying subtypes of tumors likely to respond remains difficult. The use of lipids as a nutrient source is of particular importance, especially in breast cancer. Imaging techniques offer the opportunity to quantify nutrient use in preclinical tumor models to guide development of new drugs that restrict uptake or utilization of these nutrients. We describe a fast and dynamic approach to image fatty acid uptake in vivo and demonstrate its relevance to study both tumor metabolic reprogramming directly, as well as the effectiveness of drugs targeting lipid metabolism. Specifically, …

A Mechanism Behind The Mechanotransduction Of Surface Characteristics In Osteoblasts, Otto J. Juhl Iv

Theses and Dissertations

Biomaterials for use in bone regeneration and healing range from metal and metal alloy implants to hydrogel-based solutions. These materials can be optimized to increase bone healing and integration by improving the mechanical and biological properties. Regardless of the material itself, the cell-substrate interaction is key to the success of the biomaterial once implanted. Substrate surface characteristics such as roughness, wettability, and particle density are well-known contributors to a substrate’s overall osteogenic potential, and therefore the substrate's overall success. Unfortunately, it is still unknown how these substrate surface characteristics are transduced into intracellular signals by cells, preventing specific tailoring of …

Impact Of Hemodynamic Vortex Spatial And Temporal Characteristics On Analysis Of Intracranial Aneurysms, Kevin W. Sunderland

Dissertations, Master's Theses and Master's Reports

Subarachnoid hemorrhage is a potentially devastating pathological condition in which bleeding occurs into the space surrounding the brain. One of the prominent sources of subarachnoid hemorrhage are intracranial aneurysms (IA): degenerative, irregular expansions of area(s) of the cerebral vasculature. In the event of IA rupture, the resultant subarachnoid hemorrhage ends in patient mortality occurring in ~50% of cases, with survivors enduring significant neurological damage with physical or cognitive impairment. The seriousness of IA rupture drives a degree of clinical interest in understanding these conditions that promote both the development and possible rupture of the vascular malformations. Current metrics for the …

Stobe Photography Mapping Of Cell Membrane Potential With Nanosecond Resolution, Allen S. Kiester, Bennett L. Ibey, Zachary N. Coker, Andrei G. Pakhomov, Joel N. Bixler

Bioelectrics Publications

The ability to directly observe membrane potential charging dynamics across a full microscopic field of view is vital for understanding interactions between a biological system and a given electrical stimulus. Accurate empirical knowledge of cell membrane electrodynamics will enable validation of fundamental hypotheses posited by the single shell model, which includes the degree of voltage change across a membrane and cellular sensitivity to external electric field non-uniformity and directionality. To this end, we have developed a high-speed strobe microscopy system with a time resolution of ~ 6 ns that allows us to acquire time-sequential data for temporally repeatable events (non-injurious …

Engineering Stimuli-Responsive Polymeric Nanoassemblies: Rational Designs For Intracellular Delivery Of Biologics, Kingshuk Dutta

Doctoral Dissertations

Biologic drugs have gained enormous research attention in recent years as reflected by the development of multiple candidates to the clinical pipelines and an increased percentage of FDA approval. This is reasoned by the fact that biologics have been proven to deliver more predictive and promising benefits for many hard-to-cure diseases by ‘drugging the undruggable’ targets. However, the challenges associated with biologic drug development are multi-fold, viz, poor encapsulation efficacy, systemic instability, low cellular internalization and endosomal escape capability. Thus, it is essential to develop new molecular strategies that can not only address the associated drug delivery challenges, but also …

Engineering Mesothelin-Binding Proteins As Targeted Cancer Diagnostics And Therapeutics, Allison Rita Sirois

Doctoral Dissertations

Cancer is a significant global health concern; and traditional therapies, including chemotherapeutics, are often simultaneously toxic yet ineffective. There is a critical need to develop targeted cancer therapeutics which specifically inhibit molecules or molecular pathways essential for tumor growth and maintenance. Furthermore, a targeted therapy is only effective when a patient's tumor expresses the molecular target; therefore, companion diagnostics, including molecular imaging agents, are a necessary counterpart of targeted therapies. Mesothelin (MSLN) is a cell surface protein overexpressed in numerous cancers, including triple-negative breast, pancreatic, ovarian, liver, and lung, with limited expression in normal tissues. Aberrant MSLN expression promotes tumor …

Micro-Physiological Models To Mimic Mucosal Barrier Complexity Of The Human Intestine In Vitro, Abhinav Sharma

Doctoral Dissertations

The mucosal barrier in the intestine is vital to maintain selective absorption of nutrients while protecting internal tissues and maintaining symbiotic relationship with luminal microbiota. This bio-barrier consists of a cellular epithelial barrier and an acellular mucus barrier. Secreted mucus regulates barrier function via in situ biochemical and biophysical interaction with luminal content that continually evolves during digestion and absorption. Increasing evidence suggests that a mucus barrier is indispensable to maintain homeostasis in the gastrointestinal tract. However, the importance of mucus barrier is largely underrated for in vitro mucosal tissue modeling. The major gap is the lack of experimental material …

Biomechanical And Biophysical Properties Of Breast Cancer Cells Under Varying Glycemic Regimens, Diganta Dutta, Xavier-Lewis Palmer, Jose Ortega-Rodas, Vasundhara Balraj, Indrani Ghosh Dastider, Surabhi Chandra

Electrical & Computer Engineering Faculty Publications

Diabetes accelerates cancer cell proliferation and metastasis, particularly for cancers of the pancreas, liver, breast, colon, and skin. While pathways linking the 2 disease conditions have been explored extensively, there is a lack of information on whether there could be cytoarchitectural changes induced by glucose which predispose cancer cells to aggressive phenotypes. It was thus hypothesized that exposure to diabetes/high glucose alters the biomechanical and biophysical properties of cancer cells more than the normal cells, which aids in advancing the cancer. For this study, atomic force microscopy indentation was used through microscale probing of multiple human breast cancer cells (MCF-7, …

Modulation Of Ros In Nanosecond-Pulsed Plasma-Activated Media For Dosage-Dependent Cancer Cell Inactivation In Vitro, Chunqi Jiang, Esin Bengisu Sozer, Shutong Song, Nicola Lai, P. Thomas Vernier, Sigi Guo

Bioelectrics Publications

Dosage control of reactive oxygen and nitrogen species (RONS) is critical to low-temperature plasma applications in cancer therapy. Production of RONS by atmospheric pressure, nonequilibrium plasmas in contact with liquid may be modulated via plasma conditions including plasma treatment time and pulse voltage and repetition frequency. In this study, a terephthalic acid-based probe was used to measure hydroxyl radicals [OH_aq] in water exposed to plasma and to demonstrate that the OH_ag concentration increases linearly with treatment time. Fluorometric measurements of hydrogen peroxide concentration in plasma-activated water show a linear relationship between the H₂O₂ production …