Molecular, Cellular, and Tissue Engineering Commons^™

Using Crosslinked Hyaluronic Acid (Ha) And Collagen Scaffolds With Sustained Brain-Derived Neurotrophic Factor (Bdnf) Release For Post-Sci Nerve Regeneration, Panth Doshi

Undergraduate Research Posters

Traumatic events resulting in spinal cord injuries (SCIs) often leave people paralyzed or with partial loss of motor function. The physical disabilities arising from traumatic events prevent people from functioning at the same level as pre-injury. My work aims to identify a plausible method to overcome the inhibitory post-SCI environment and to regenerate nervous tissue in order to restore neural function and, subsequently, motor function. I identified components of a new, hypothetical nerve scaffold based on the immune response after SCIs and the efficacy of currently used scaffolds for nerve regeneration. Hyaluronic acid (HA) polymer scaffolds and collagen-based scaffolds are …

Surface Functionalization Via Photoinitiated Radical Polymerization For Rare Cell Isolation And Mechanical Protection, Calvin Frank Cahall

Theses and Dissertations--Chemical and Materials Engineering

Surface functionalization of living cells for cell therapeutics has gained substantial momentum in the last two decades. From encapsulating islets of Langerhans, to cell laden gels for tissue scaffolds, to individual cell encapsulation in thin hydrogels, to surface adhesives and inert surface camouflage, modification of living cell surfaces has a wide array of important applications. Here we use hydrogel encapsulation of individual cells as a mode of protection from mechanical forces for high throughput cell printing, and chemical stimuli for the isolation of rare cells in blood.

In the first study, we review methods of surface functionalization and establish a …

A Purification And In Vitro Activity Assay For A (P)Ppgpp Synthetase From Clostridium Difficile, Astha Pokhrel, Asia Poudel, Erin B. Purcell

Chemistry & Biochemistry Faculty Publications

Kinase and pyrophosphokinase enzymes transfer the gamma phosphate or the beta-gamma pyrophosphate moiety from nucleotide triphosphate precursors to substrates to create phosphorylated products. The use of γ-³²-P labeled NTP precursors allows simultaneous monitoring of substrate utilization and product formation by radiography. Thin layer chromatography (TLC) on cellulose plates allows rapid separation and sensitive quantification of substrate and product. We present a method for utilizing the thin-layer chromatography to assay the pyrophosphokinase activity of a purified (p)ppGpp synthetase. This method has previously been used to characterize the activity of cyclic nucleotide and dinucleotide synthetases and is broadly suitable for …

Subject-Independent Emotion Recognition Based On Physiological Signals: A Three-Stage Decision Method, Jing Chen, Bin Hu, Yue Wang, Philip Moore, Yongqiang Dai, Lei Feng, Zhijie Ding

Biomedical Engineering Faculty Publications

Background: Collaboration between humans and computers has become pervasive and ubiquitous, however current computer systems are limited in that they fail to address the emotional component. An accurate understanding of human emotions is necessary for these computers to trigger proper feedback. Among multiple emotional channels, physiological signals are synchronous with emotional responses; therefore, analyzing physiological changes is a recognized way to estimate human emotions. In this paper, a three-stage decision method is proposed to recognize four emotions based on physiological signals in the multi-subject context. Emotion detection is achieved by using a stage-divided strategy in which each stage deals with …

Reducing Biomass Recalcitrance By Heterologous Expression Of A Bacterial Peroxidase In Tobacco (Nicotiana Benthamiana), Ayalew Ligaba-Osena, Bertrand Hankoua, Kay Dimarco, Robert Pace, Mark Crocker, Jesse Mcatee, Nivedita Nagachar, Ming Tien, Tom L. Richard

Center for Applied Energy Research Faculty and Staff Publications

Commercial scale production of biofuels from lignocellulosic feed stocks has been hampered by the resistance of plant cell walls to enzymatic conversion, primarily owing to lignin. This study investigated whether DypB, the lignin-degrading peroxidase from Rodococcus jostii, depolymerizes lignin and reduces recalcitrance in transgenic tobacco (Nicotiana benthamiana). The protein was targeted to the cytosol or the ER using ER-targeting and retention signal peptides. For each construct, five independent transgenic lines were characterized phenotypically and genotypically. Our findings reveal that expression of DypB in the cytosol and ER does not affect plant development. ER-targeting increased protein accumulation, and …

Effects Of Uniaxial Cyclic Strain On Endothelial Progenitor Cells, Maria Alejandra Zeballos Castro

Biomedical Engineering Undergraduate Honors Theses

Despite the high prevalence of calcific aortic valve disease (CAVD), the underlying mechanisms of pathogenesis have not been found yet. Therefore, it is extremely important to study CAVD and understand how it develops. For this matter, we decided to study the potential of endothelial progenitor cells (EPCs) for use in tissue-engineered models of heart valves. EPCs were chosen as the cell source of interest for this study due to their high neovascularization potential and use in regenerative medicine and cardiovascular tissue engineering.

In this project, we aimed to engineer the microenvironment of cells that are involved in the formation of …

Elucidating The Mechanical, Structural, Functional, And Molecular Mechanisms Involved In Irreversible Vascular Changes In Aortic Coarctation, Brandon Wegter

Master's Theses (2009 -)

Coarctation of the aorta (CoA) is a constriction of the thoracic aorta and is one of the most common congenital cardiovascular defects. Treatment by surgical correction has saved the lives of thousands of children, but many still have a reduced lifespan due to hypertension. Previous results using our novel rabbit model showed that the current treatment guideline of a 20 mmHg blood pressure gradient (BPG) induces irreversible vascular changes, which persisted despite correction. Preliminary data of the downregulation of natriuretic peptide receptor C (NPR-C) in proximal aortic tissue of human patients with CoA serves as the possible underlying mechanism for …

Cross-Species Complementation Reveals Conserved Functions For Early Flowering 3 Between Monocots And Dicots, He Huang, Malia A. Gehan, Sarah E. Huss, Sohpie Alvarez, Cesar Lizarraga, Ellen L. Gruebbling, John Gierer, Michael J. Naldrett, Rebacca K. Bindbeutel, Bradley S. Evans, Todd C. Mockler, Dmitri A. Nusinow

Nebraska Center for Biotechnology: Faculty and Staff Publications

Plant responses to the environment are shaped by external stimuli and internal signaling pathways. In both the model plant Arabidopsis thaliana (Arabidopsis) and crop species, circadian clock factors are critical for growth, flowering, and circadian rhythms. Outside of Arabidopsis, however, little is known about the molecular function of clock gene products. Therefore, we sought to compare the function of Brachypodium distachyon (Brachypodium) and Setaria viridis (Setaria) orthologs of EARLY FLOWERING 3, a key clock gene in Arabidopsis. To identify both cycling genes and putative ELF3 functional orthologs in Setaria, a …

Influence Of Fibroblasts On Functional Arteriogenesis In A Murine Chronic Hindlimb Ischemia Model, Ashli A. Santos

Biomedical Engineering

Peripheral arterial occlusive disease (PAOD) occurs when there is a narrowing or blockage – usually a buildup of plaque - within the arteries that reduces blood flow to tissues which can chronic ischemia. As with most diseases, early detection and proactive treatment are important to maximize prognosis. Exercise effectively treats PAOD, but due to ischemic pain in the limbs, or intermittent claudication (IC), exercise can become painful and difficult. Due to the buildup of plaque, occlusions create an ischemic environment that changes the pressure distribution in collateral networks and increases the shear stress in transverse collaterals. Those two responses signal …

Three-Dimensional Microfluidic Tumor Vascular Model For Investigating Breast Cancer Metastasis, Anastasiia Vasiukhina, Brian H. Jun, Luis Solorio, Pavlos P. Vlachos

The Summer Undergraduate Research Fellowship (SURF) Symposium

Metastasis is one of the primary reasons for the high mortality rates in female patients diagnosed with breast cancer. It involves the migration of cancer cells into the circulatory system allowing for the dissemination of cancer cells in distal tissues. Understanding the major processes that occur in cells and tissues during metastasis can help improve currently existing therapeutic methods. In order to understand such mechanisms, developing physiologically relevant tissue models is crucial. Advancements in microfluidics have led to the fabrication of 3D culture models with shear stress gradients and flow control that can recapitulate aspects of the tumor microenvironment in …

Localized Immunosuppression Therapy For Islet Cell Encapsulation, Madeline Mclaughlin, Clarissa Stephens, Sherry Voytik-Harbin

The Summer Undergraduate Research Fellowship (SURF) Symposium

Type 1 diabetes, an autoimmune disease in which the body’s immune system destroys the insulin-producing beta cells necessary for managing a person’s blood glucose levels, affects 1.25 million Americans. A potential treatment for this disease is islet cell transplantation where Islets of Langerhans, containing the beta cells, are transplanted from a normal donor to a diabetic recipient to regulate blood glucose levels and provide insulin independence. Similar to whole organ transplantation, immune modulation through immunosuppression therapy is necessary for successful transplantation of islets without rejection. However, long-term systemic immunosuppression therapy can be toxic to the patient and the islets. Because …

Establishing A Lung Model For Evaluation Of Engineered Lung Microbiome Therapies, Kathryn F. Atherton, Stephen Miloro, Jenna Rickus

The Summer Undergraduate Research Fellowship (SURF) Symposium

Benzene, a toxin and carcinogen found in air polluted by cigarette smoke, car exhaust, and industrial processes, is associated with the development of leukemia and lymphoma. Other than avoiding exposure, there is no current method to deter the effects of benzene. One potential strategy to prevent these effects is to engineer the bacteria of the human lung microbiome to degrade benzene. To evaluate this novel approach, we must verify that the bacteria remain viable within the lung microenvironment. To do so, lungs were harvested from rats and swabbed to determine the contents of the original lung microbiome. Then green fluorescent …

A Novel High-Throughput, High-Content Three-Dimensional Assay For Determination Of Tumor Invasion And Dormancy, Mahera M. Husain, Theodore J. Puls, Sherry Voytik-Harbin

The Summer Undergraduate Research Fellowship (SURF) Symposium

Metastasis accounts for most cancer deaths, while dormancy of tumor cells leads to unexpected cancer recurrence. These two aspects of cancer remain relatively untreatable in part because current two-dimensional (2D) methods of high-throughput drug screening cannot quantify outcomes related to these phenotypes. Three-dimensional (3D) in-vitro tumor models are a promising alternative because they better recreate the tumor microenvironment and relevant phenotypes. However, outcome measures for high-throughput screening of these systems are often limited to single measures such as metabolic activity using assays that are not standardized or optimized for 3D models. To address this gap, the objective of this work …

Fret Biosensors: Engineering Fluorescent Proteins As Biological Tools For Studying Parkinson’S Disease, Nathan J. Leroy, Jacob R. Norley, Saranya Radhakrishnan, Mathew Tantama

The Summer Undergraduate Research Fellowship (SURF) Symposium

Parkinson’s Disease (PD) is a common neurodegenerative disease with over 200,000 new cases each year. In general, the cause of the disease is unknown, but oxidative stress inside of neurons has been associated with the disease’s pathology for some time. Currently, techniques to study the onset of PD inside of neurons are limited. This makes treatments and causes difficult to discover. One solution to this has been fluorescent protein biosensors. In short, these proteins can be engineered to glow when a certain state is achieved inside a cell. The present research discusses the engineering of a genetically-encoded fluorescent protein (FP) …

Multi-Color Ultra-High Resolution Imaging, David A. Miller, Michael Mlodzianoski, Sheng Liu, Fang Huang

The Summer Undergraduate Research Fellowship (SURF) Symposium

Fluorescence microscopy, which allows multiple-color imaging, plays an important role in observing structures inside cells with high specificity. The advent of super-resolution fluorescence microscopy, or nanoscopy techniques such as single-molecule switching nanoscopy (SMSN), has extended the application range of fluorescence microscopy beyond the diffraction limit, achieving up to 10-fold improvement in spatial resolution. At the same time, the recent development of expansion microscopy (ExM) allows samples to be physically expanded by 4-fold in the lateral dimensions providing another independent method to resolve structures beyond the diffraction limit. When combined, ExM-SMSN makes it possible to achieve another significant leap in resolution …

A Spatial Stochastic Model Of Ampar Trafficking And Subunit Dynamics, Tyler Vandyk, Matthew C. Pharris, Tamara L. Kinzer-Ursem

The Summer Undergraduate Research Fellowship (SURF) Symposium

In excitatory neurons, the ability of a synaptic connection to strengthen or weaken is known as synaptic plasticity and is thought to be the cellular basis for learning and memory. Understanding the mechanism of synaptic plasticity is an important step towards understanding and developing treatment methods for learning and memory disorders. A key molecular process in synaptic plasticity for mammalian glutamatergic neurons is the exocytosis (delivery to the synapse) of AMPA-type glutamate receptors (AMPARs). While the protein signaling pathways responsible for exocytosis have long been investigated with experimental methods, it remains unreasonable to study the system in its full complexity …

Intravenous Administration Of Iron Oxide Nanoparticles In The Chicken Model, Huong Thi Ngoc Le

Graduate Theses and Dissertations

To be used in health care, the safety and effectiveness of nanoparticles needs to be tested in a living organism. The objective of this project was to develop the chicken as a convenient animal model to examine tissue targeting of intravenously (i.v.)-injected iron oxide (IO) nanoparticles. In Experiment 1, different doses of IO-COOH were i.v. injected into chickens; blood was collected at 0, 5, 15, 30, and 60 minutes post-injection; liver, spleen, lung, and kidney were collected after the last blood collection. For Experiment 2, IO-COOH and IO-PEG were i.v. injected into chickens; blood and the organs were collected at …

Isolation And Culture Of Myofiber-Derived Cells From The Extensor Digitorum Longus Muscle, Ethan M. Tietze

Biomedical Engineering

Peripheral arterial occlusive disease (PAOD) involves distal artery occlusion by atherosclerotic plaques, which restricts blood flow and leads to ischemia in downstream tissues. Increased blood flow through preexisting collateral vessels leads to increased shear stress that triggers an outward remodeling of the vessel called arteriogenesis. In some cases this natural compensatory mechanism is able to sufficiently restore blood flow following arterial occlusion. However, for many individuals this process is insufficient to relieve peripheral ischemia, and patients experience intermittent claudication, or limb pain with locomotion or exercise. Without treatment, reduced blood flow can lead to tissue necrosis and potentially amputation. The …

Development And Characterization Of Tissue Engineered Blood Vessel Mimics Under "Diabetic" Conditions, Shelby Gabrielle Kunz

Master's Theses

The development of tissue engineered blood vessel mimics for the testing of intravascular devices in vitro has been established in the Cal Poly tissue engineering lab. Due to the prevalence of cardiovascular disease in diabetic patients and minimal accessible studies regarding the interactions between diabetes and intravascular devices used to treat vascular disease, there is a need for the development of diabetic models that more accurately represents diabetic processes occurring in the blood vessels, primarily endothelial dysfunction. This thesis aimed to create a diabetic blood vessel mimic by implementing a high glucose environment for culturing human endothelial cells from healthy …

The Impact Of The Mitochondrial Metabolism Of Induced Pluripotent Stem Cells Upon Differentiation, Stefanie T. Shahan

McKelvey School of Engineering Graduate Student Theses & Dissertations

Induced pluripotent stem cells (iPSCs) can be differentiated into any cell type found in the body. The derivation of a stem cell derived β cell (SC-β) capable of responding to glucose by secreting insulin was hugely significant for diabetes research and opened up the possibility of cell replacement therapy to combat this widespread disease (Pagliuca et al. 2014). The optimization of differentiation procedures such as this could improve yield, function, cost, and efficiency of a stem cell-derived product. Current approaches to improve differentiation are primarily focused on signal transduction pathways, while the metabolic state of the cells has received little …