Biomedical Engineering and Bioengineering Commons^™

Beyond The Fiber: Novel Spider Silk Coatings And Adhesives, Danielle A. Gaztambide, Breton A. Day

Research on Capitol Hill

Natural spider silks have long been recognized for their combination of incredible strength and elasticity. Spider silk is more elastic than nylon, tougher than Kevlar, and stronger than steel by weight. Due to an inability to farm spiders, much work has been done to produce spider silks in transgenic hosts for large -scale production. Our work was done using recombinant spider silk proteins produced in transgenic goats and the bacteria E. coli.

More recently spider silks have also been recognized for their biocompatibility and lack of immunogenicity. Spider silks' incredible strength and ability to be implanted safely within the body …

Supernormal Conduction And Suppression Of Spatially Discordant Alternans Of Cardiac Action Potentials, Linyuan Jing, Anuj Agarwal, Abhijit R. Patwardhan

Biomedical Engineering Faculty Publications

Spatially discordant alternans (DA) of action potential durations (APD) is thought to be more pro-arrhythmic than concordant alternans. Super normal conduction (SNC) has been reported to suppress formation of DA. An increase in conduction velocity (CV) as activation rate increases, i.e., a negative CV restitution, is widely considered as hallmark of SNC. Our aim in this study is to show that it is not an increase in CV for faster rates that prevents formation of DA, rather, it is the ratio of the CV for the short relative to the long activation that is critical in DA suppression. To illustrate …

Cold Atmospheric Plasma Inhibits Hiv-1 Replication In Macrophages By Targeting Both The Virus And The Cells., Olga Volotskova, Larisa Dubrovsky, Michael Keidar, Michael Bukrinsky

Microbiology, Immunology, and Tropical Medicine Faculty Publications

Cold atmospheric plasma (CAP) is a specific type of partially ionized gas that is less than 104°F at the point of application. It was recently shown that CAP can be used for decontamination and sterilization, as well as anti-cancer treatment. Here, we investigated the effects of CAP on HIV-1 replication in monocyte-derived macrophages (MDM). We demonstrate that pre-treatment of MDM with CAP reduced levels of CD4 and CCR5, inhibiting virus-cell fusion, viral reverse transcription and integration. In addition, CAP pre-treatment affected cellular factors required for post-entry events, as replication of VSV-G-pseudotyped HIV-1, which by-passes HIV receptor-mediated fusion at the plasma …

Ex-Vivo Slaughterhouse Porcine Crystalloid-Perfused Beating Heart Via Langendorff Method, Rahiemin Talukder

Electronic Theses and Dissertations

The objective of this study was to resuscitate isolated beating porcine hearts obtained from slaughterhouse swine for a minimum of 1 hour with a crystalloid buffer reperfusion instead of blood via an extracorporeal Langendorff apparatus. The isolated beating heart functions outside of the body under simulated physiologic conditions. Live functional anatomy was controlled under benchtop experimental settings. Porcine hearts (26 total) were topically cooled with saline. 300mL of 25°C cardioplegia with 20KU Streptokinase was preflushed via aortic root. WIT was less than 5 minutes. 1L 4°C cardioplegia was flushed antegrade with aortic cannula (Group 1) or coronary catheterization (Group 2). …

Pch1 Integrates Circadian And Light- Signaling Pathways To Control Photoperiod-Responsive Growth In Arabidopsis, He Huang, Chan Yul Yoo, Rebecca Bindbeutel, Jessica Goldsworthy, Allison Tielking, Sophie Alvarez, Michael J. Naldrett, Bradley S. Evans, Meng Chen, Dmitri A. Nusinow

Nebraska Center for Biotechnology: Faculty and Staff Publications

Plants react to seasonal change in day length through altering physiology and development. Factors that function to harmonize growth with photoperiod are poorly understood. Here we characterize a new protein that associates with both circadian clock and photoreceptor components, named PHOTOPERIODIC CONTROL OF HYPOCOTYL1 (PCH1). pch1 seedlings have overly elongated hypocotyls specifically under short days while constitutive expression of PCH1 shortens hypocotyls independent of day length. PCH1 peaks at dusk, binds phytochrome B (phyB) in a red light-dependent manner, and co-localizes with phyB into photobodies. PCH1 is necessary and sufficient to promote the biogenesis of large photobodies to maintain an …

Quantitative Comparison Of A Nanoengineered Alumina Coated Cnt Arrays To Sio2 Coated Cnts And Solution Based Delivery System, Shree Aier

Maseeh Summer Undergraduate Research Experience

To meet the growing need for nanoengineered biocompatible materials to serve as drug delivery platforms, in this research, carbon nanotube arrays were fabricated by chemical vapor deposition, followed by an alumina coating by the high yielding, tightly controlled atomic layer deposition. This nanoengineered vertically aligned alumina nanowire array serves as a platform for delivering antigens, which act as cancer adjuvants. The physicochemical characteristics of the nanowires (NWs) can significantly influence the delivery of a biomolecule to immune cells. To investigate the material characteristics, the delivery efficiency of the antigen using NWs was quantitatively assessed by flow cytometry. Further, the mechanism …

Effect Of Twisted Fiber Anisotropy In Cardiac Tissue On Ablation With Pulsed Electric Fields, Fei Xie, Christian W. Zemlin

Bioelectrics Publications

Background: Ablation of cardiac tissue with pulsed electric fields is a promising alternative to current thermal ablation methods, and it critically depends on the electric field distribution in the heart.

Methods: We developed a model that incorporates the twisted anisotropy of cardiac tissue and computed the electric field distribution in the tissue. We also performed experiments in rabbit ventricles to validate our model. We find that the model agrees well with the experimentally determined ablation volume if we assume that all tissue that is exposed to a field greater than 3 kV/cm is ablated. In our numerical analysis, we considered …

Cell Electrosensitization Exists Only In Certain Electroporation Buffers, Janja Dermol, Olga N. Pakhomova, Andrei G. Pakhomov, Damijan Miklavčič

Bioelectrics Publications

Electroporation-induced cell sensitization was described as the occurrence of a delayed hypersensitivity to electric pulses caused by pretreating cells with electric pulses. It was achieved by increasing the duration of the electroporation treatment at the same cumulative energy input. It could be exploited in electroporation-based treatments such as electrochemotherapy and tissue ablation with irreversible electroporation. The mechanisms responsible for cell sensitization, however, have not yet been identified. We investigated cell sensitization dynamics in five different electroporation buffers. We split a pulse train into two trains varying the delay between them and measured the propidium uptake by fluorescence microscopy. By fitting …

Cytosolic Dna Sensor Upregulation Accompanies Dna Electrotransfer In B16.F10 Melanoma Cells, Katarina Znidar, Masa Bosnjak, Maja Cemazar, Loree C. Heller

Bioelectrics Publications

In several preclinical tumor models, antitumor effects occur after intratumoral electroporation, also known as electrotransfer, of plasmid DNA devoid of a therapeutic gene. In mouse melanomas, these effects are preceded by significant elevation of several proinflammatory cytokines. These observations implicate the binding and activation of intracellular DNA-specific pattern recognition receptors or DNA sensors in response to DNA electrotransfer. In tumors, IFN β mRNA and protein levels significantly increased. The mRNAs of several DNA sensors were detected, and DAI, DDX60, and p204 tended to be upregulated. These effects were accompanied with reduced tumor growth and increased tumor necrosis. In B16. F10 …

Aconitic Acid, Glycerol And Cinnamic Acid Polyester Characterization For Bone Tissue Engineering, Katie Joanna Hogan

Honors Capstones

No abstract provided.

Restriction And Characterization Of Human Breast Cancer Using A Three-Dimensional Embryonic Stem Cell Model, Bridget Mooney

Legacy Theses & Dissertations (2009 - 2024)

Human breast cancer is currently the highest diagnosed form of cancer and the second leading cause of cancer-related deaths in American women. Triple negative breast cancer is of the basal subtype and displays the worst prognosis owing to its highly metastatic properties. Current treatments focused on eradicating breast tumors in lieu of or following local therapy include chemotherapy, hormonal therapy, and targeted therapy. Hormonal therapy is not an option for triple negative breast cancer as it does not contain hormone receptors and there are currently no approved biological targeted therapies. Chemotherapy has proven unsuccessful because triple negative breast cancer is …

Investigation Of Enzymatically Synthesized Glycogen As A Novel Nanodendrimer For Therapeutic Delivery, Sarah Ann Engelberth

Legacy Theses & Dissertations (2009 - 2024)

The field of medicinal chemistry is ever expanding, designing and discovering new therapeutic strategies. Oftentimes, it is challenging for these therapeutics to undergo clinical translation due to ineffective administration or unwanted toxicity in vivo. As such, drug delivery vehicles are designed to overcome these hurdles, allowing for delivery to the site of action by improving biodistribution, protecting therapeutic cargo, and decreasing toxicity. The work presented here aims to investigate a naturally-derived carbohydrate nanodendrimer, enzymatically synthesized glycogen (ESG) for drug delivery. This nontoxic, highly-branched, glucose-based structure has interior void volumes to allow for cargo encapsulation as well as a large density …

Anticancer, Biophysical And Computational Investigations Of Half-Sandwich Ruthenium(Ii) Thiosemicarbazone Complexes: The Effect Of Arene Versus Thiacrown Face-Cap, Floyd A. Beckford, Alyssa Stott, P. Canisius Mbarushimana, Marc-Andre Leblanc, Kinsey Hall, Samantha Smith, Jimmie L. Bullock, Dennis J. Houghton, Alvin A. Holder, Nikolay Gerasimchuk, Antonio Gonzalez-Sarrías

Chemistry & Biochemistry Faculty Publications

A series of half-sandwich ruthenium complexes, two containing an arene face-cap and the other a thiacrown ether face-cap were synthesized to investigate the necessity of the arene for anticancer activity in this class of compounds. The complexes are formulated as [(h⁶-p-cymene)Ru(dmabTSC)Cl]PF₆, [(h⁶-benzene)Ru(dmabTSC)Cl]PF₆ (arene complexes), and [([9]aneS₃(dmabTSC)Cl]PF₆ (dmabTSC = dimethylaminobenzaldehye thiosemicarbazone). It was observed that none of the complexes showed good anticancer activity in vitro against HCT-116 and Caco-2 (colon adenocarcinoma) cells. All three complexes can bind strongly to calf-thymus DNA with binding constants on the order of 10 …

Development And Application Of Gadolinium Free Cardiac Magnetic Resonance Fibrosis Imaging For Multiscale Study Of Heart Failure In Patients With End Stage Renal Disease, Tori A. Stromp

Theses and Dissertations--Physiology

Cardiac magnetic resonance (CMR) is a powerful tool to noninvasively image ventricular fibrosis. Late gadolinium enhancement (LGE) CMR identifies focal and, with T1 mapping, diffuse fibrosis. Despite prevalent cardiac fibrosis and heart failure, patients with end stage renal disease (ESRD) are excluded from LGE. Absence of a suitable diagnostic has limited the understanding of heart failure and obstructed development of therapies in the setting of ESRD. A quantitative, gadolinium free fibrosis detection method could overcome this critical barrier, propelling the advancement of diagnostic, monitoring, and therapy options. This project describes the development of a gadolinium free CMR technique and application …

A Flexible Pet-Based Wearable Sensor For Arterial Pulse Waveform Measurement, Dan Wang, Dean Krusienski, Zhili Hao

Mechanical & Aerospace Engineering Faculty Publications

In light of the need of health monitoring, the paper presents a flexible polyethylene terephthalate (PET)-based wearable sensor for arterial pulse waveform measurement. The sensor encompasses a polydimethylsiloxane (PDMS) microstructure embedded with an electrolyte-enabled 5×1 transducer array, which spans 6mm and has a spatial resolution of 1.5mm. A pulse signal exerts a deflection on the microstructure and is recorded as a resistance change by a transducer at the site of the pulse. An untrained individual can easily align the sensor on a targeted artery with a negligible margin and then acquire the arterial pulse waveform continuously and non-invasively. This sensor …

Automated Solid-Substrate Cultivation Of The Anaerobic Bacterium Clostridium Thermocellum, Mathew J. Ruwaya

Theses and Dissertations--Biosystems and Agricultural Engineering

The organism Clostridium thermocellum grows on cellulosic substrates and produces ethanol, acetate, lactate, formic acid, and CO₂. The organic acids produced alter the growth environment in which the bacteria grows and ultimately inhibit bacterial growth. One method which has been used successfully to maintain the system at acceptable growth conditions is to intermittently flush out the spent media and metabolic products and replace with new fermentation media. Our goal was to design and build an automated system that will automatically flush the spent media from the growing culture and resupply new media without manual intervention. An automated control …

Radio-Frequency Plasma Polymerized Biodegradable Carrier For In Vivo Release Of Cis-Platinum, Sudhir Bhatt, Fatemeh Valamanesh, Jerome Pulpytel, Rea Lo Dico, Aliby Baiyukha, Iman Al-Dybiat, Marc Pocard, Farzaneh Arefi-Khonsari, Massoud Mirshahi

Bioelectrics Publications

A low pressure plasma process based on plasma deposition has been used to develop a drug delivery strategy. In this study, a drug delivery system based on different layers of plasma co-polymerized Poly ε-caprolactone-Polyethylene glycol (PCL-PEG) co-polymers was deposited on biocompatible substrates. Cis-platinum (118 μgm/cm²) was used as an anti-cancer drug and incorporated for local delivery of the chemotherapeutic agent. The co-polymer layers and their interaction with cancer cells were analyzed by scanning electron microscopy. Our study showed that the plasma-PCL-PEG coated cellophane membranes, in which the drug, was included did not modify the flexibility and appearance of …

The Role Of E-Cadherin Force In The Maintenance Of Homeostasis In Epithelial Acini, Fnu Vani Narayanan

Theses and Dissertations

Numerous three-dimensional model systems have emerged for emulating the biochemical and physiological states of native tissue. Yet little is known about the effects of mechanical forces on cell behavior in the context of an organized tissue structure in three-dimensional cell-culture. Epithelial cells cultured in a three-dimensional environment comprised of extracellular matrix proteins form spheroids of polarized cells. Cellular responses to mechanical cues, generated from dynamic interactions with the extracellular matrix and neighboring cells, are known to influence cellular behavior to a great extent. Previous studies have shown that tumorigenic progression has been frequently linked to the down regulation of E-cadherin, …

Fluorescent Nanocomposite Of Embedded Ceria Nanoparticles In Crosslinked Pva Electrospun Nanofibers, Nader Shehata, Soha Gaballah, Effat Samir, Aya Hamed, Marwa Saad

Biology Faculty Publications

This paper introduces a new fluorescent nanocomposite of electrospun biodegradable nanofibers embedded with optical nanoparticles. In detail, this work introduces the fluorescence properties of PVA nanofibers generated by the electrospinning technique with embedded cerium oxide (ceria) nanoparticles. Under near-ultra violet excitation, the synthesized nanocomposite generates a visible fluorescent emission at 520 nm, varying its intensity peak according to the concentration of in situ embedded ceria nanoparticles. This is due to the fact that the embedded ceria nanoparticles have optical tri-valiant cerium ions, associated with formed oxygen vacancies, with a direct allowed bandgap around 3.5 eV. In addition, the impact of …

Accessible Bioprinting: Adaptation Of A Low-Cost 3d-Printer For Precise Cell Placement And Stem Cell Differentiation, John A. Reid, Peter A. Mollica, Garett D. Johnson, Roy C. Ogle, Robert D. Bruno, Patrick C. Sachs

School of Medical Diagnostics & Translational Sciences Publications

The precision and repeatability offered by computer-aided design and computer-numerically controlled techniques in biofabrication processes is quickly becoming an industry standard. However, many hurdles still exist before these techniques can be used in research laboratories for cellular and molecular biology applications. Extrusion-based bioprinting systems have been characterized by high development costs, injector clogging, difficulty achieving small cell number deposits, decreased cell viability, and altered cell function post-printing. To circumvent the high-price barrier to entry of conventional bioprinters, we designed and 3D printed components for the adaptation of an inexpensive 'off-the-shelf' commercially available 3D printer. We also demonstrate via goal based …

Effects Of High Voltage Nanosecond Electric Pulses On Eukaryotic Cells (In Vitro): A Systematic Review, Tina Batista Napotink, Matej Reberšek, P. Thomas Vernier, Babara Mali, Damijan Miklavčič

Bioelectrics Publications

For this systematic review, 203 published reports on effects of electroporation using nanosecond high-voltage electric pulses (nsEP) on eukaryotic cells (human, animal, plant) in vitro were analyzed. A field synopsis summarizes current published data in the field with respect to publication year, cell types, exposure configuration, and pulse duration. Published data were analyzed for effects observed in eight main target areas (plasma membrane, intracellular, apoptosis, calcium level and distribution, survival, nucleus, mitochondria, stress) and an additional 107 detailed outcomes. We statistically analyzed effects of nsEP with respect to three pulse duration groups: A: 1–10 ns, B: 11–100 ns and C: …

Nanosecond Pulsed Platelet-Rich Plasma (Nsprp) Improves Mechanical And Electrial Cardiac Function Following Myocardial Reperfusion Injury, Barbara Y. Hargrave, Frency Varghese, Nektarios Barabutis, John Catravas, Christian Zemlin

School of Medical Diagnostics & Translational Sciences Publications

Ischemia and reperfusion (I/R) of the heart is associated with biochemical and ionic changes that result in cardiac contractile and electrical dysfunction. In rabbits, platelet-rich plasma activated using nanosecond pulsed electric fields (nsPRP) has been shown to improve left ventricular pumping. Here, we demonstrate that nsPRP causes a similar improvement in mouse left ventricular function. We also show that nsPRP injection recovers electrical activity even before reperfusion begins. To uncover the mechanism of nsPRP action, we studied whether the enhanced left ventricular function in nsPRP rabbit and mouse hearts was associated with increased expression of heat-shock proteins and altered mitochondrial …

Noninvasive Measurement Of Electrical Events Associated With A Single Chlorovirus Infection Of A Microalgal Cell, Seung-Woo Lee, Eun-Hee Lee, Gerhard Thiel, James L. Van Etten, Ravi Saraf

Department of Chemical and Biomolecular Engineering: Faculty Publications

Chlorovirus Paramecium bursaria chlorella virus 1 (PBCV-1) contains a viral-encoded K⁺ channel imbedded in its internal membrane, which triggers host plasma membrane depolarization during virus infection. This early stage of infection was monitored at high resolution by recording the cell membrane depolarization of a single Chlorella cell during infection by a single PBCV-1 particle. The measurement was achieved by depositing the cells onto a network of one-dimensional necklaces of Au nanoparticles, which spanned two electrodes 70 μm apart. The nanoparticle necklace array has been shown to behave as a single-electron device at room temperature. The resulting electrochemical field-effect transistor …

Bioactivity/Cytotoxicity Of Micro-/Nano-Materials And Novel Development Of Fiber-Optic Probes For Single Cell Monitoring, Qingbo Yang

Doctoral Dissertations

"Manufactured nano-/micro-materials (MNMs) have been widely used and their interactions with niche biological environment are highly concerned for both of their biohazardous and bioactive effects, whereas no available comprehensive evaluations or regulations have been provided yet. This dissertation thus focuses on three major aspects: 1) fundamental toxicity understandings of a typical MNMs (zinc oxide nanoparticles), 2) bioactivity evaluations of representative bioactive MNMs, and 3) development of novel micro-probes for high spatial resolution monitoring. Firstly, the NP's concentration, irradiation, hydrodynamic size, and the localized pH, ionic strength, NP zeta-potential as well as dissolved oxygen levels were found correlated with the production …

Inhibition Of Bacterial Growth And Prevention Of Bacterial Adhesion With Localized Nitric Oxide Delivery, Julia Osborne

Dissertations, Master's Theses and Master's Reports

Bacterial infections continue to be a problem at the site of an indwelling medical device, and over the years, various bacterial strains have become more resistant to current antibiotic treatments. Bacterial infection at an indwelling medical device can be dangerous and affect the performance of the medical device which can ultimately lead to the failure of the device due to bacterial resistance to treatment.

Nitric Oxide (NO) has been shown to possess antibacterial properties to prevent and inhibit bacterial growth. NO releasing coatings on indwelling medical devices could provide a reduction in bacterial infections that occur at the device site …

Investigation Of The Inherent Chemical, Structural, And Mechanical Attributes Of Bio-Engineered Composites Found In Nature: Alligator Gar’S Exoskeleton Fish Scales, Wayne Derald Hodo

Graduate Theses and Dissertations

The U.S. Army has determined a huge cost savings of up to 51% can be accomplished by reducing the gross vehicle weight, for their personnel carrier, by 33%. To cut cost, composite materials are needed. Man-made composites can have superior material properties (high-strength, high-fracture toughness, and lightweight), but they are prone to delamination at the glued-layered interface. In contrast, fish scale is a natural composite that has the same material properties and, additionally, tend not to delaminate.

The focus of this study was to learn how nature integrates hard and soft materials at each length scale to form a layered …

Background Differences In Baseline And Stimulated Mmp Levels Influence Abdominal Aortic Aneurysm Susceptibility, Matthew A. Dale, Melissa K. Suh, Shijia Zhao, Trevor Meisinger, Linxia Gu, Vicki J. Swier, Devendra K. Agrawal, Timothy Greiner, Jeffrey S. Carson, B. Timothy Baxter, Wanfen Xiong

Department of Mechanical and Materials Engineering: Faculty Publications

Objective: Evidence has demonstrated profound influence of genetic background on cardiovascular phenotypes. Murine models in Marfan syndrome (MFS) have shown that genetic background-related variations affect thoracic aortic aneurysm formation, rupture, and lifespan of mice. MFS mice with C57Bl/6 genetic background are less susceptible to aneurysm formation compared to the 129/SvEv genetic background. In this study, we hypothesize that susceptibility to abdominal aortic aneurysm (AAA) will be increased in 129/SvEv mice versus C57Bl/6 mice. We tested this hypothesis by assessing differences in aneurysm size, tissue properties, immune response, and MMP expression.

Methods: Mice of C57Bl/6 or 129/SvEv background underwent AAA induction …

Compounds Released From Biomass Deconstruction: Understanding Their Effect On Cellulose Enzyme Hydrolysis And Their Biological Activity, Angele Djioleu

Graduate Theses and Dissertations

The effect of compounds produced during biomass pretreatment on cellulolytic enzyme was investigated. Liquid prehydrolyzates were prepared by pretreating switchgrass using 24 combinations of temperature, time, and sulfuric acid concentration based on a full factorial design. Temperature was varied from 140°C to 180°C; time ranged from 10 to 40 min; and the sulfuric acid concentrations were 0.5% or 1% (v/v). Identified products in the prehydrolyzates included xylose, glucose, hydroxymethylfurfural (HMF), furfural, acetic acid, formic acid, and phenolic compounds at concentration ranging from 0 to 21.4 g/L. Pretreatment conditions significantly affected the concentrations of compounds detected in prehydrolyzates. When assayed in …

Storage Of Round And Square Switchgrass Bales: Effect Of Storage Time And Fungal Inoculation On Saccharification Efficiency, Noaa Frederick

Graduate Theses and Dissertations

To produce fermentable sugars from lignocellulosic biomass feedstock, severe pretreatment conditions are needed (either high acid concentration, temperature, or retention times). High severities can produce toxic byproducts which inhibit enzymatic hydrolysis or fermentation. In order to reduce pretreatment severities (and thus increase enzyme and fermentation efficiency), the white-rot fungus Pleurotus ostreastus was seeded into square and round bales of Kanlow switchgrass (Panicum virgastum L.) and left in the field over a period of 9 month. The laccase producing fungus is believed to selectively degrade lignin, a common plant structural polymer, which can function as an enzymatic inhibitor. Samples were taken …

Next-Generation Mrna Sequencing Reveals Pyroptosis-Induced Cd4+ T Cell Death In Early Simian Immunodeficiency Virus-Infected Lymphoid Tissues, Wuxun Lu, Andrew J. Demers, Fangrui Ma, Guobin Kang, Zhe Yuan, Yanmin Wan, Yue Li, Jiangqing Xu, Mark Lewis, Qingsheng Li

Nebraska Center for Biotechnology: Faculty and Staff Publications

Lymphoid tissues (LTs) are the principal sites where human immunodeficiency virus type 1 (HIV-1) replicates and virus-host interactions take place, resulting in immunopathology in the form of inflammation, immune activation, and CD4+ T cell death. The HIV-1 pathogenesis in LTs has been extensively studied; however, our understanding of the virus-host interactions in the very early stages of infection remains incomplete. We investigated virus-host interactions in the rectal draining lymph nodes (dLNs) of rhesus macaques at different times after intrarectal inoculation (days postinoculation [dpi]) with simian immunodeficiency virus (SIV). At 3 dpi, 103 differentially expressed genes (DEGs) were detected using next-generation …