Biomedical Engineering and Bioengineering Commons^™

Restoring An Iso:5840-Compliant Pulse Duplicator Device For Hydrodynamic Performance Characterization Of Artificial Cardiac Valves, Denver Eagar

Biomedical Engineering Undergraduate Honors Theses

During the summer of 2021, I was employed as an intern at Dynatek Labs, an implantable prosthetics testing company located in southern Missouri. My primary project was to modernize an abandoned pulse duplicator device and protocol to allow the company to re-enter a market area which they left nearly 15 years prior: heart valve testing. The company halted this initiative due to changes in international testing standards in previous years. The International Standards Organization Cardiac Valves Working Group released the latest version of standards concerning artificial heart valve testing (ISO 5840) in January of 2021. Accordingly, my project required that …

Static Force Analysis Of A Porcine Mitral Valve To Determine Self-Supporting Capabilities Of The Leaflets, Jacob Paris

Biomedical Engineering Undergraduate Honors Theses

The mitral valve (MV) is responsible for controlling the flow between the left atrium (LA) and left ventricle (LV). This includes maintaining valve closure under high systolic pressures. Mitral regurgitation (MR) occurs when the valve fails to completely close and blood flows in the reverse direction, from the LV to the LA, during ejection. This type of valvular heart disease is prevalent among elderly individuals and is becoming increasingly common as the population ages. In order to better understand how to properly treat this large group of affected individuals, the mechanics of the MV during high systolic pressures must be …

Developing Aligned Nerve Scaffolds In A 3d Type-I Collagen Gel, Gabriel David

Biomedical Engineering Undergraduate Honors Theses

Despite significant progress in the field of peripheral nerve repair, clinical success is still limited, leaving millions to suffer from peripheral neuropathy with billions spent every year for treatment. Nerve repair methods that are capable of maximizing the regenerative properties of peripheral nerves are greatly desired in the field of medical science. This research aims to fill the gap between modern methods and the future of nerve repair by creating type-I collagen scaffolds with aligned degradation pores that will assist and nurture nerves growing through them. This is achieved by incorporating adipose stem cells into type-I collagen hydrogels and aligning …

New Force Transducer For Mitral Valve Chordae Tendinea, Joseph Berryman

Biomedical Engineering Undergraduate Honors Theses

In order to inform the future of mitral valve repair and replacement, more investigation into the mechanics of the sub-valvular structure is needed. Understanding the roles of each chord during valve closure requires a sensor capable of detecting these small forces with enough sensitivity to determine the characteristics of each of the chordal types. The focus of the cantilever force transducer is to maximize this sensitivity while also minimizing the invasiveness of the sensor on the overall function of the chord. The design utilizes flexible yet strong 3D printed resin and cantilever arms to improve the strain exerted on a …

Redesign And Quantitative Assessment Of An Accelerated Venous Valve Fatigue Apparatus, Megan Kueh

Biomedical Engineering Undergraduate Honors Theses

Chronic venous insufficiency (CVI) is a form of cardiovascular disease that is caused when valves in the leg become incompetent. Current treatment methods serve to manage symptoms, but there are currently no ways to treat the underlying cause of CVI. A venous valve prosthetic made from a xenograft of a bovine jugular vein is one possible treatment method currently in the research phase. Prosthetic valves must be tested with an accelerated wear tester prior to approval for clinical testing. Although such testers exist for heart valves, physiological differences between heart and venous valves restrict the use those testers on venous …

Development Of A Matlab Gui To Assist The Active Comprehension Of Biomedical Transport Phenomena Using A Visual Aid, Pranav Suri

Biomedical Engineering Undergraduate Honors Theses

Studies show that inductive teaching methods for Biomedical Transport Phenomena greatly benefit from an accompanying visual aid. The following project aimed to develop a MATLAB GUI application that illustrates steady-state heat transfer with a graph and heat map using user-defined boundary conditions and numerical parameters. The application was evaluated using a survey that first familiarized the user with the GUI by running through heat transfer exercises, then allowed the user to experiment with the application, and finally asked users about their experiences using a questionnaire. The responses indicate that the GUI was received positively overall, and that a MATLAB component …

The Response Of Astrocytes To Mechanical Stimuli, Courtney Bahan

Biomedical Engineering Undergraduate Honors Theses

Traumatic brain injuries are a common cause of injury and result from a blow to the head whether it be blunt, penetrating, or inertial. TBIs are typically obtained in a fall, while playing a sport, or in a car crash. TBIs can be diagnosed as mild (commonly referred to as a concussion), moderate, or severe based upon their score from the Glasgow coma scale. TBIs can also lead to other risks such as epilepsy or Alzheimer’s Disease as well as increasing the risk of suffering another TBI. Astrocytes are heterogeneous glial cells in the brain that alter their response based …

Design Of Microporous Membranes For The Development Of Brain-On-Chip Devices, Andre Figueroa Milla

Biomedical Engineering Undergraduate Honors Theses

Traumatic brain injuries (TBIs) are a major global health concern that have an economic impact of $60 billion in the United States in related costs annually. Developing drugs for TBI treatment is an approach that currently faces limitations involving the permeability of the blood-brain barrier (BBB). The BBB naturally limits molecules from reaching the brain as a protective mechanism against disease, acting as a barrier during drug delivery. Understanding the BBB mechanically and chemically following a TBI could potentially assist future studies to alleviate the symptoms and long-term effects of TBI by pharmaceuticals. The Mechanobiology and Soft Materials Laboratory (MSML) …

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 …

Role Of Angiotensin I And Ii On The Tissue Mechanics Of The Aortic Heart Valve Via Receptor Binding And Converting Enzymes, Josh Fahy

Biomedical Engineering Undergraduate Honors Theses

The renin-angiotensin system (RAS) plays a crucial role in the regulation of renal, cardiac, and vascular physiology. This system regulates in vivo blood pressure and fluid balance. As renal blood flow decreases, the kidneys convert prorenin into renin and secrete it into the circulatory system. Renin then converts angiotensinogen into angiotensin I (ang-I). The ang-I is then converted into angiotensin II (ang-II) by the angiotensin-converting enzyme (ACE). Ang-II, a vasoconstrictor, increases blood pressure by causing the blood vessels to narrow. Recent evidence suggests that RAS may be involved in the progression of valve disease, most notably, aortic stenosis.

The first …

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 …

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 …

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. …

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 …

Development And Analysis Of A Statics And Kinematics Demonstration As A Learning Tool In The Biomechanics Classroom, Bethany D. Knight

Biomedical Engineering Undergraduate Honors Theses

This study was done with the objective of determining if students in the biomedical engineering department at the University of Arkansas would gain better understanding of basic biomechanics principles through the implementation of in-class demonstrations. Biomechanics was chosen because it is the first class taken in sequence after the “Introduction to Biomedical Engineering” class. A pre-demonstration survey was administered to gauge how comfortable the students were with the topics on the syllabus. Two demonstrations were done in class and related homework was assigned. The post-semester survey was administered and collected to determine how effective the students felt the presentations to …

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 …