Biomedical Engineering and Bioengineering Commons^™

Comparing The Effects Of Fibroblast Growth Factors On Growth Rate Of Human Fibroblast Cell Lines, Tasha Repella

Biomedical Engineering Undergraduate Honors Theses

Numerous studies have demonstrated the usefulness of growth factors in medium formulations to promote proliferation and viability of human fibroblasts in laboratory settings. However, due to the differences in the source and age of fibroblasts, the ability of growth factors like hFGF1 to promote proliferation varies. Equally difficult is the ability of hFGF1 to promote proliferation of diseased fibroblasts due to complexities associated with specific mitochondrial diseases. In this context, we decided to evaluate the potential for novel hyper stable growth factors super hFGF and hFGF1 (shFGF and hFGF1 respectively), to contribute to proliferation of different normal and diseased fibroblasts. …

Development Of A Model For Accelerated Fatigue Testing In Venous Valves, Olga Brazhkina

Biomedical Engineering Undergraduate Honors Theses

Malfunctioning venous cause issues ranging from cosmetic to life threatening situations for millions of people in the U.S. (1). Venous valve bioprosthetics often fail due to a loss in leaflet tissue flexibility following chemical fixation of donor tissue (2). A viable solution for testing venous valves prior to and post chemical fixation is in high demand for the development of a more durable prosthetic replacement. As a result, this research aims to create a fatigue apparatus that provides a means to model the durability of venous valves. The design criteria for this project included modeling physiological conditions in an accelerated …

Modeling And Validation Of Tissue Optical Properties In The Photon Transport Regime, Katelyn Heath

Biomedical Engineering Undergraduate Honors Theses

Early detection of changes in epithelial cells, such as the development of neoplastic formations seen in epithelial dysplasia, can indicate regions of the epithelial tissue that are at a high risk for cancerous formation. Using concepts from diffuse reflectance spectroscopy, a Monte Carlo model was developed to predict the reflectance measured by a detector at a small source-detector separation on a microendoscope. The Monte Carlo results were then used to calculate a mathematical relationship between the reflectance and distance that can be used to determine optical properties in a tissue sample. This model was validated with liquid phantoms of specified …

Designing An In Vitro Mitral Valve Mounting And Testing System For Micro Ct Imaging, Marinna Tadros

Biomedical Engineering Undergraduate Honors Theses

Five million people in the US are diagnosed with valvular disease, of which mitral valve disease is one of the most common. Computational models are informed by high resolution images and have the potential to aid in diagnosing and establishing surgical plans to treat mitral valve diseases. Existing methods using 7T MRI imaging have limitations such as small bore diameter, long imaging times and difficulty in maintaining trans-mitral fluid pressure throughout the scan. Imaging with Micro CT allows for efficient scan times and eliminates bore size constraints which allows for imaging more sizes and types of MVs. There is a …

Vector Flow Imaging In Pediatric Cardiology - Extracting And Validating Data, Mason Belue

Biomedical Engineering Undergraduate Honors Theses

In the field of bedside cardiac diagnostic imaging, Doppler Ultrasound (DU) is the gold standard for diagnosing heart conditions. The largest benefit of DU is its ability to noninvasively image cardiac flow and allow the estimation of blood velocity and quantification of anatomical disease. However, to get correct velocity estimation, the position of the transducer in relation to the flow field needs to be known. This is the problem of angle/direction dependency and limits DUs accuracy when imaging in areas where perfect alignment or exact position of the transducer in relation to flow field is not possible or known, such …

3d Printed Force Transducers For In-Vitro Mitral Valve Chordae Tendineae Force Measurements, Hayley Chandler

Biomedical Engineering Undergraduate Honors Theses

Mitral valve surgery is incredibly prevalent in the United States with more than 40,000 mitral valve surgical procedures annually. Improving the imaging techniques used to diagnose these cases requires validation of 3D models through experimental data such as mechanical properties of the tissue. An essential part of this process for the mitral valve is measuring the force experienced by chordae tendineae. This has been achieved with brass force transducers but using a 3D printed design can have many benefits. In this study, 3D printed miniature c-shaped force transducers comparable to previous metal models were designed and created using Solidworks 2016. …

Quantification Of Tumor-Associated Macrophages Following Immunomodulation Therapy In A Murine Allograft Model Of Colorectal Carcinoma, Caroline Spainhour

Biomedical Engineering Undergraduate Honors Theses

Colorectal Carcinoma (CRC) is one of the deadliest cancers in the world, with 150,000 new cases annually in the United States. Traditional treatments include chemotherapy and invasive surgery; however, research has shown that only 25% of patients that undergo traditional treatment have a positive result. Immunotherapy is an emerging form of cancer treatment that utilizes the patients’immune system to fight cancer cells by targeting inflammation, which plays a large role in the proliferation and metastasis of cancer cells.

Tumor-associated macrophages (TAMs) are immune cells that affect the inflammatory microenvironment of tumors. TAMs are M1 in the early stages of tumors, …

Role Of Local Renin-Angiotensin System In Altering Valve Interstitial Cell Phenotype, Sophia Scalise

Biomedical Engineering Undergraduate Honors Theses

Hypertension is a disorder prevalent in adults around the world and is a common attributable cause of heart disease and mortality [1]. Calcification is much more common in the aortic valve than the other three heart valves [2]. Aortic valve interstitial cells (VICs), the principal cell type found in the human aortic valve, have been linked to disease development when they change in phenotype to become osteoblast like cells [3]. The phenotypes of these cells play a role in the development of calcification in the aortic valves [4].

Angiotensin II is a hormone in the body that has been implicated …

Antibacterial Properties Of A Cationic Imidazolium-Containing Poly(Ionic Liquid), Kaitlyn P. Brickey

Biomedical Engineering Undergraduate Honors Theses

Poly(ionic liquids), or PILs, have been shown to have a number of biological applications as ligands, drug delivery vehicles, and nonviral DNA delivery mechanisms. Additionally, PILs have been proven to be efficient antibacterials. Imidazolium-containing PILs have promising results in antibacterial studies, but relating to their chain and charge density, only the effects of mono- & bis-imidazolium PILs have been sufficiently described in literature. The work detailed in this thesis aimed to further existing research on the effect of chain density by controlling the UV-initiator immobilization time. The effects of chain density were investigated by grafting poly(vinylimidazolium chloride) onto SiO_{2 …}

In-Vitro Simulation Of Acute Ischemic Stroke, Paolo Garcia

Biomedical Engineering Undergraduate Honors Theses

Acute ischemic stroke (AIS) is a condition that involves the occlusion of a blood vessel within the brain, effectively preventing the passage of oxygen and nutrients. AIS is highly prevalent in the United States, where nearly 795,000 strokes happen per year and 87% of those are ischemic. From a medical standpoint, the obstructing clot can be removed with the use of a stroke retrieval device. However, a need arises for testing the aforementioned devices on a patient’s specific vascular geometries in order to increase the likelihood of a successful procedure. Outlined is a process for developing a physical simulation of …

Development Of An In Vitro Platform For The Exploration Of Skeletal Muscle Cell Mechanobiology, Sydney Spradlin

Biomedical Engineering Undergraduate Honors Theses

Muscles have the natural ability to regenerate when damaged. This works to keep the body functioning, unless this ability is overwhelmed. Volumetric muscle loss (VML) occurs when a substantial amount of a muscles mass is lost. This leads to the development of scar tissue, and often a loss of function. In order to find a solution for this condition, in vitro models are needed to explore the mechanobiology of skeletal muscle cells. Two platforms were developed in this study, to explore 3 factors: orientation, strain, and supporting structure. One platform used fibronectin stamped lanes on PDMS to encourage cell growth …

Pressure Acquisition System For In Vitro Mitral Valve Analysis, Laura Peck

Biomedical Engineering Undergraduate Honors Theses

In vitro testing of the mitral valve chordae tendineae is utilized to aid in the understanding of the stresses that occur in vivo and improve upon surgical solutions that exist for mitral valve repair. This project aimed to design the water control system for a left heart simulation chamber, as well as the pressure acquisition inside the chamber. A solenoid valve was utilized to control the water supply to the tank and was powered utilizing National Instruments software. National Instruments hardware and software was also used with the pressure transducer in order to obtain pressure readings from the chamber. The …

Comparison Of Varying Tissue Freezing Methods On Murine Colonic Tissue, James Hughes

Biomedical Engineering Undergraduate Honors Theses

Histology often requires a tissue specimen to be embedded so that it may be sectioned, stained, and mounted on a microscope slide for viewing. One common method of tissue embedding for rapid histology is freezing, since freezing allows tissue to be stored without the need for fixing. Frozen tissue is often embedded in a medium such as Optimal Cutting Temperature (OCT) compound so that it can be sectioned using a cryostat. However, factors such as ice-crystal formation during the freezing process can cause damage to the tissue. As such, the protocol used to freeze the tissue can affect the quality …

Effects Of Gsk101 Exposure On Astrocyte Mechanical Properties, Collagen Production, And Viability, Ethan Echols

Biomedical Engineering Undergraduate Honors Theses

Transient receptor potential vanilloid 4 (TRPV4) is a cation channel protein which is thought to facilitate extracellular matrix (ECM) modification and glial scar formation following traumatic brain injury (TBI). Activation of TRPV4 has been shown to correlate with an increase in intracellular Ca²⁺ concentration. TRPV4 is subject to both chemical and mechanical activation. This study involved chemical activation of TRPV4 in cultured mouse astrocytes using GSK101, the primary agonist of TRPV4, and subsequent evaluation of mechanical and chemical changes to the ECM. Prior to GSK101 exposure, the cells were seeded into Matrigel Matrix, a gelatinous protein mixture intended to …

The Effect Of Elastin Degradation On The Biomechanical Properties Of Porcine Aortic Tissue, Caleb Nissen

Biomedical Engineering Undergraduate Honors Theses

The rupture of abdominal aortic aneurysms (AAA) is currently the 13^th leading cause of death in the United States [1]. AAA is characterized, in part, by an increase in presence of proteolytic enzymes which degrade the structural proteins collagen and elastin [6]. The goal of this study was to examine the effect that elastin degradation has on the biomechanical properties of aortic tissue. For this experiment, porcine aortic tissue was cut in the circumferential and longitudinal directions. These specimens were exposed to an elastase solution for varying time-intervals and then underwent uniaxial tensile testing. Elastase-treated tissue tested in the …

Extraction And Analysis Of Vector Flow Imaging Data In A Pediatric Population, Bailey Stinnett

Biomedical Engineering Undergraduate Honors Theses

Vector flow imaging (VFI) is a new ultrasound technology that provides real time, angle-independent visualization of flow velocities in the heart and great vessels. Thus far, VFI has been used for superficial applications due to the limited penetration depth of available transducer probes; however, this depth in smaller pediatric patients enables adequate aortic views. In this project, VFI was used to study pediatric aortic stenosis (PAS)—a congenital heart defect that results in the narrowing of the aorta and/or aortic valve. The decision to refer PAS patients for surgical or catheter-based intervention is initially based on Doppler ultrasound. VFI is potentially …

Analysis Of Biological Response To Ecm Hydrogel Injection, Grady Dunlap

Biomedical Engineering Undergraduate Honors Theses

Abstract

Under normal circumstances, skeletal muscle possesses the capacity to regenerate and heal via inflammatory and myogenic pathways. In cases of severe tissue loss or certain diseases, this capacity is lost, often resulting in loss of tissue function. Extracellular matrix (ECM), the protein scaffold which houses cells in physiological tissue, has been shown to have structural and chemical properties which influence cell migration and phenotype. This results in ECM’s capacity to encourage a regenerative response when implanted into severely damaged skeletal muscle. Additional advantages are apparent when an ECM scaffold is digested into a hydrogel, namely less invasive implantation via …

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 …

Optical Imaging Of Metabolic Adaptability As A Biomarker For Metastatic Potential In Breast Cancer Cells, Mason G. Harper

Biomedical Engineering Undergraduate Honors Theses

Breast cancer metastasis is the main cause for mortality in breast cancer patients. However, knowledge of metastatic recurrence is limited, and there is a need to understand metastatic recurrence in order to treat breast cancer patients more effectively. Highly invasive metastatic breast cancer has shown to exhibit metabolic adaptability, transitioning from glycolysis to oxidative phosphorylation in the presence of microenvironmental stress. NADH and FAD are naturally occurring cofactor products during glycolysis and oxidative phosphorylation, respectively, and they are of particular importance during these metabolic processes due to their endogenous fluorescence. Measuring the ratio of fluorescence intensities of these cofactors through …

Age's Effect On Regenerative Capabilities Of Myocytes Through Satellite Cell Analysis, Karam S. Sra

Biomedical Engineering Undergraduate Honors Theses

The objective of this study was to investigate potential effects aging had on muscle fiber area and satellite cell count in myocytes. This research could help elucidate the detrimental effect age has on regenerative capabilities whether in terms of satellite cell function or satellite cell number. Satellite cells are primarily responsible for generating new muscle tissue after being activated through mechanotransduction of injury. This study utilized immunofluorescence to examine the presence of the PAX7 gene expression, a unique marker of satellite cells, within a 12 month and 18 month old population of mice. The PAX7 marker was co-stained with DAPI …

Detection Of Leukocytes Stained With Acridine Orange Using Unique Spectral Features Acquired From An Image-Based Spectrometer, Courtney J. Hunter

Biomedical Engineering Undergraduate Honors Theses

A leukocyte differential count can be used to diagnosis a myriad blood disorders, such as infections, allergies, and efficacy of disease treatments. In recent years, attention has been focused on developing point-of-care (POC) systems to provide this test in global health settings. Acridine orange (AO) is an amphipathic, vital dye that intercalates leukocyte nucleic acids and acidic vesicles. It has been utilized by POC systems to identify the three main leukocyte subtypes: granulocytes, monocytes, and lymphocytes. Subtypes of leukocytes can be characterized using a fluorescence microscope, where the AO has a 450 nm excitation wavelength and has two peak emission …

Characterization Of The Response Of Trpv4 To Chemical Stimulation, Jacob V. Schluns

Biomedical Engineering Undergraduate Honors Theses

Traumatic Brain Injury (TBI) is a source of acute and chronic health issues for many patients. One of the components of the brain’s response to injury is astrogliosis, in which astrocytes that normally function to repair the brain instead form scar tissue that halts repair processes. Transient Receptor Potential Vanilloid Type 4 (TRPV4) is a trans-membrane calcium channel involved in astrogliosis. Through Fura-2AM based calcium imaging, the base activity of this channel in mouse astrocyte cells was recorded. The cells were then subjected to TRPV4 agonist and antagonist stimulation and their subsequent activity levels were recorded. The data showed that …

Optimizing A Standard Fasting Time For 2-Nbdg Uptake Studies In Murine Breast Cancers, Andrew C. Briley

Biomedical Engineering Undergraduate Honors Theses

Recently, there has been a larger use of 2-NBDG, a fluorescent glucose analog, to study glucose uptake in different cell types. These cell types have ranged anywhere from bacteria to human cancer cells. However, there has yet to be a standard procedure and practice for using 2-NBDG. In this study, our goal is to create a standard fasting time for the cells before introducing 2-NBDG to them. This study uses 4T07 cells, a murine breast cancer cell line, to help optimize this fasting time. These cells were fasted at different time points in order to find the ideal fasting time. …

In Vivo Multi-Parametric Imaging Of Metastatic And Non-Metastatic Breast Cancer, Raisa B. Rasul

Biomedical Engineering Undergraduate Honors Theses

A current issue in cancer therapy is the characterization of metastatic tumors, which can increase ease of treatment and patient trials. We present an in vivo study of metastatic (4T1) and non-metastatic (4T1-TWIST KO) breast tumor sister cell lines to understand their metabolic behavior, determine differences in two modes of imaging (reflection & transmission), and observe effect of breathing higher oxygen percentage on vascular hemoglobin oxygen saturation. After injection of 10,000 cells into mice dorsal window chambers, the glucose intake and hemoglobin oxygen saturation was measured using a fluorescent glucose analog (2-NBDG) and hyperspectral trans-illumination imaging from 520-620 nm at …

Metabolic Response To Stress Differentiates Heterogeneous Cancer Cells With Varying Metastatic Potential, Kinan Alhallak

Biomedical Engineering Undergraduate Honors Theses

Intratumoral heterogeneity is ubiquitously present within primary tumors and contributes to intractable behaviors such as metastasis and mutability spatiotemporally. Mounting evidence has shown that heterogeneous cell populations can adversely affect cell metabolism and metastatic potential. The cell’s only fluorescent molecules within the electron transport chain, flavin adenine dinucleotide (FAD) and nicotinamide adenine dinucleotide (NADH), can allow the quantitation of cell metabolism. We demonstrate the use of the optical redox ratio (FAD/(NADH+FAD)) to determine the metabolic behaviors of a heterogeneous panel of cells with varying metastatic programs at normal conditions and following acute hypoxia. At normal conditions, we reveal an attenuation …

Role Of Trpv4 In Astrocyte Extracellular Matrix Production, Abby Terlouw

Biomedical Engineering Undergraduate Honors Theses

Traumatic Brain Injury (TBI) is an alteration of brain pathology following damage of the central nervous system (CNS) by an external force. In the CNS, glial scar formation often occurs following TBI, and astrocytes are widely believed to contribute to this scar formation. While the role of astrocytes in extracellular matrix (ECM) production is known, the exact mechanism(s) for this event remain unclear. One possible method is the activation of transient receptor potential vanilloid 4 (TRPV4). TRPV4 is a channel protein found in the astrocyte membrane which has been shown to generate intracellular calcium ions following mechanical stimulation. Previous research …

Localized Immunotherapy Delivery Using Injectable In Situ Forming Chitosan Hydrogel, Seth Washispack

Biomedical Engineering Undergraduate Honors Theses

Cytokine-based cancer immunotherapies stimulate a host’s immune system to fight cancer. In particular, interleukin-12 (IL-12), a potent pro-inflammatory cytokine, has demonstrated the ability to eliminate tumors in a number of preclinical models. Toxicities associated with the systemic delivery of IL-12 have precluded its use in the clinic. We are developing a novel chitosan-based hydrogel to maintain high local concentrations of cytokines, such as IL-12, in the tumor while minimizing its systemic dissemination. This hydrogel was found to form spontaneously within ten seconds of mixing two proprietary components. To increase the usefulness of the hydrogel, an efficient mixing and delivery system …

Chitosan As An Antiviral, Tayler Pauls

Biomedical Engineering Undergraduate Honors Theses

There is no broad-based antiviral medication available today; there are specific antivirals, for example, the antiretroviral for HIV. However, these specific antivirals are not available in each country and can be problematic for specific patients. Chitosan is proposed as a possible broad-based antiviral, which has already demonstrated antibacterial properties, antiviral properties in plants, is used for wound healing and as a hydrogel among other medical applications. The methods used are transfection of NIH-3T3 cells with GFP-adenovirus with 0.1%, 0.5%, and 1% chitosan added to virus prior to transfection. Fluorescence microscopy and flow cytometry data has validated that the use of …

Determining The Effect Of Delivery Rate On Glucose Uptake By Cancer Cells, Luke Felton

Biomedical Engineering Undergraduate Honors Theses

Radiation therapy is one of the most commonly performed cancer treatment therapies today. Radiation therapy can cause can changes to tumor vasculature and affect blood flow rates. It is important to determine how changes in blood flow rates affect tumor glycolytic uptake to better understand tumor response to radiation therapy (1). The goal of this study was to use a fluorescent analog of glucose, 2-NBDG, to study the effect of varying flow rates on glucose uptake. A microfluidic device was constructed to flow 2-NBDG through. A murine metastatic breast cancer cell line was then cultured inside this microfluidic channel, and …

Isolation Of Metallic Single-Walled Carbon Nanotubes For Electrically Conductive Tissue Engineering Scaffolds, Jakob Hockman

Biomedical Engineering Undergraduate Honors Theses

Metallic single-walled carbon nanotubes (m-SWNTs) were separated from pristine SWNTs using affinity chromatography for use in electrically conductive tissue engineering scaffolds. Approximately one third of SWNTs have metallic properties. Separations were achieved using a protocol modified from Liu & coworkers (2011) in order to improve the method for cell culture environments. Samples enriched in m-SWNTs were isolated and characterized. However, challenges still remain for the complete separation of m-SWNTs from their semiconducting counterpart (s-SWNTs) using this protocol. Approaches to improve separation and reduce the difficulties associated with processing the nanotubes were suggested. One of the ultimate destinations of these nanotubes …