Engineering Commons^™

Shape Memory Alloy Capsule Micropump For Drug Delivery Applications, Youssef Mohamed Kotb

Theses and Dissertations

Implantable drug delivery devices have many benefits over traditional drug administration techniques and have attracted a lot of attention in recent years. By delivering the medication directly to the tissue, they enable the use of larger localized concentrations, enhancing the efficacy of the treatment. Passive-release drug delivery systems, one of the various ways to provide medication, are great inventions. However, they cannot dispense the medication on demand since they are nonprogrammable. Therefore, active actuators are more advantageous in delivery applications. Smart material actuators, however, have greatly increased in popularity for manufacturing wearable and implantable micropumps due to their high energy …

Redesign Of Leg Assembly For Remote Walking Training Device To Improve Gait Kinematics, Jacob Anthony

Mechanical Engineering Theses

As modern medicine has improved, the average age of patients has increased. This has cause a growing number of patients to develop disabilities over time due to spinal cord injuries and stroke among other neurological ailments. This has led to an increased interest in developing robotic exoskeletons to help patients with neuromuscular rehabilitation. However, most exoskeletons do not accurately replicate the natural human gait kinematics due to a lack of degrees of freedom at the designed knee joint. In this thesis, the leg assembly for a robotic rehabilitation (RoboREHAB) device is redesigned to improve the gait kinematics and a reinforcement …

Integrating Implantable Bci Devices Within Bci2000 Using A Unified Framework And Toolchain For In-Vivo Research, Dhruva Mehta

McKelvey School of Engineering Theses & Dissertations

The field of neurotechnology research has a bright and promising future as more devices are created. However, there are still many gaps in the field as the potential for neuromodulation grows. Devices such as the Micro-Leads StimZ system and the Ripple Grapevine/Summit system help bridge that gap by allowing for a broader variety of closed-loop neuromodulation experiments to be implemented thanks to their portability and versatility. Despite these devices being on the market, however, there needs to be a method to collaborate and interact with them across multiple research institutions. BCI2000 helps to address that by creating a standardized working …

Evaluating Neuroimaging Modalities In The A/T/N Framework: Single And Combined Fdg-Pet And T1-Weighted Mri For Alzheimer’S Diagnosis, Peiwang Liu

McKelvey School of Engineering Theses & Dissertations

With the escalating prevalence of dementia, particularly Alzheimer's Disease (AD), the need for early and precise diagnostic techniques is rising. This study delves into the comparative efficacy of Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) and T1-weighted Magnetic Resonance Imaging (MRI) in diagnosing AD, where the integration of multimodal models is becoming a trend. Leveraging data from the Alzheimer's Disease Neuroimaging Initiative (ADNI), we employed linear Support Vector Machines (SVM) to assess the diagnostic potential of these modalities, both individually and in combination, within the AD continuum. Our analysis, under the A/T/N framework's 'N' category, reveals that FDG-PET consistently outperforms T1w-MRI across …

Investigating Murine Uterine Tissue Dynamics: Biomechanical And Histological Perspectives On Postpartum Involution And Scar-Induced Remodeling, Savannah Elizabeth Chatman

McKelvey School of Engineering Theses & Dissertations

During pregnancy, the uterus undergoes structural and mechanical transformations to withstand the demands of a successful delivery. In cases where vaginal birth is not feasible, a Cesarean section (c-section), which involves a transverse abdominal incision, is used to facilitate delivery of the fetus and placenta¹. Following the procedure, the uterus and abdominal tissue are carefully sutured to support postpartum recovery, leading to uterine scarring at the incision site^1,2. Understanding the relationship between uterine scar integrity, postpartum involution, and the biomechanics of uterine tissue is a crucial step toward predicting the risk of uterine rupture during future …

Analyzing Heat Generated From Electro-Osmotic Flow Utilizing Computational Fluid Dynamics, Jordan Elizabeth Grothe

Honors Thesis

Without extensive vascularization, the transfer of fluid and nutrients through human tissue is limited to diffusion and weak interstitial flow. Electroosmosis, or the flow of fluid driven by an electrical field, has become a promising solution. Scientists have begun applying electricity to human tissue to promote stronger interstitial flow; however, optimization of this process has proven to be a challenge due to ohmic heating. Cells function within a small range of temperatures and exposure to voltages exceeding the threshold will cause cells to degrade and die prematurely. This research seeks to better understand and quantify the range of voltage where …

Computational Predictions Of Heart Failure Drug Effects On Cardiac Fibrosis, Aaron Gardner

Chemical Engineering Undergraduate Honors Theses

The extracellular matrix is a complex system surrounding cells that is crucial to all of the cardiovascular system’s functions. Fibrosis is an excessive accumulation (scarring) of the extracellular matrix. Fibrosis is typically a negative event, and the scarring must be reduced in the heart in order to maintain its functionality. Due to this, simulations are run using the software “Netflux” in order to determine the effects of different heart failure drugs on cardiac fibrosis. The drugs that were simulated were an ACE Inhibitor, BAR Beta Blocker, ARB Blocker, and Entresto. These drugs were simulated over 50 hours at three different …

Evaluating Tissue Morphology In The Context Of Varied Initial Fabrication Conditions, Cassidy Caffin

Biomedical Engineering Undergraduate Honors Theses

Cardiovascular diseases have been the leading cause of death for years. This includes myocardial infarctions (MI) where blood flow to the myocardium is restricted. This causes damage to cardiac muscle due to insufficient oxygen. There are multiple ways to treat patients following an MI with the most common involving assorted medication. However, there are limited medications that can be used for treating patients following MIs, and the FDA’s decreasing approval rate for new cardiac drugs will not dramatically improve the range of options. The lead-up to drug candidate rejection by the FDA can involve drugs exhibiting promising preliminary research that …

Uv-A Light: A Novel Method For Food Dehydration, Mckade S. Roberts

All Graduate Theses and Dissertations, Fall 2023 to Present

Dehydration is one of the most prevalent forms of food preservation, with approximately 85% of food is hot air drying due to the simplicity of the process. The high temperatures employed in this method may also induce a loss in nutritional quality, which involves destruction of micronutrients (vitamins), and loss of color.

The aim of this work is to develop a low energy, non-thermal method of food dehydration that results in a high-quality product through the application of Ultraviolet light, within the UV-A range. UV light can be separated into its 3 categories based on the wavelength of light from …

Novel Kinetic Description Of Real-Time Polymerase Chain Reaction Characterizes Interrelated Effects Of Sample, Master Mix, And Cycle Time, David Tafur

All Graduate Theses and Dissertations, Fall 2023 to Present

Real-time quantitative polymerase chain reaction fluorescent curves are influenced by the quantification method, template length, primer sequence, polymerase activity, reaction conditions, and unwanted side reactions. Interpretation of these curves depends on understanding the subjacent mechanisms by which those factors can alter the curve profile, particularly on highly diluted analytes or impure samples. However, such factors are individually described today, or their interplay is not fully developed. The present work examines the effect of primer dimer formation and extension, resource competition, template reannealing, and polymerase thermodegradation, in addition to novel descriptions of polymerase competitive inhibition, extended primer amplification, and the probability …

Dorsal Root Ganglia Neurite Outgrowth Following Traumatic Spinal Cord Injury Repair: A Review, Adrienne Vaughan

Biomedical Engineering Undergraduate Honors Theses

Traumatic spinal cord injury (tSCI) can cause partial sensorimotor deficiency or total dysfunction, rendering patients unable to perform necessary tasks and dramatically decreasing their quality of life. tSCI is a very prevalent issue. In the United States alone, there are approximately 54 new cases of SCI per one million people each year, or 18,000 new cases annually. tSCI creates a lesion gap filled with axon-inhibiting fibrotic scar tissue. Comprehensive functional recovery following traumatic spinal cord injury (tSCI) requires axonal regeneration across wound site lesions. Dorsal root ganglia (DRG) neurite outgrowth is often evaluated in PNI therapeutic research since it can …

Analyzing Diverse Student Experiences: The Intersection Of Equity, Inclusivity, And Biomedical Engineering Education Through A Clinical Observations And Needs Finding Course, Jacquelynn Horsey

Biomedical Engineering Undergraduate Honors Theses

In the field of biomedical engineering, needs identification and solution development are an important element of the design process. In our undergraduate curriculum, a course was designed to allow clinical observation and provide an opportunity for students to learn about engineering design and engage with clinicians via completing rotations in medical facilities near our campus. While this type of course is not unique, evaluating its efficacy is not simple. Given the broad range of institutional resources available- such as proximity to a medical school, or residency programs- reporting the quality of such courses within the context of such available resources …

Microwave Imaging Technique For Breast Cancer Detection, Nure Alam Chowdhury

Theses and Dissertations

Breast cancer is a global problem, and it is inevitable to detect cancerous cells at early stages. In recent years, microwave imaging technology has been widely applied in biomedical applications for its non-ionizing radiation. In this study, we design a micro-strip patch antenna with an inverted T-type notch in the partial ground to detect tumor cells inside the human breast. The size of the current antenna is small enough (18 mm × 21 mm × 1.6 mm) to distribute around the breast phantom. The operating frequency has been observed from 6–14 GHz with a minimum return loss of −61.18 dB …

Environment And Response Of 3d-Encapsulated Mesenchymal Stem Cells To Mechanical Loading, Augustus Greenwood

McKelvey School of Engineering Theses & Dissertations

This thesis explores the micromechanical environment induced when cyclically compressing hydrogels via finite element modeling and experimentally on the impact of loading on mesenchymal stem cells (MSCs) when encapsulated withing 3D hydrogel matrices. Degenerative joint diseases, characterized by cartilage degradation, present significant challenges due to cartilage's limited self-repair capacity. Innovative approaches, including stem cell-based therapies and engineered biomaterials, have emerged as promising strategies for cartilage repair and regeneration. This work specifically investigates the calibration of a bioreactor, the uniformity of load response across the hydrogel constructs via finite element modeling (FEM), and the stress response of MSCs subjected to various …

Development Of A Wearable Short-Wave Infrared Photoplethysmography Device For Detection And Monitoring Of Hemodilution During Postpartum Hemorrhage, Hannah Gruensfelder

McKelvey School of Engineering Theses & Dissertations

ABSTRACT OF THE THESIS

A Thesis on the Development of a Wearable Short-Wave Infrared Photoplethysmography Device for Detection and Monitoring of Hemodilution During Postpartum Hemorrhage

by

Hannah Gruensfelder

Master of Science in Biomedical Engineering

Washington University in St. Louis, 2024

Professor Christine O’Brien, Chair

Postpartum hemorrhage (PPH), the leading cause of maternal death and morbidity, affects nearly 14 million people worldwide each year, disproportionally impacting racial minorities and people in low resource settings. A timely diagnosis of PPH is key in providing optimal patient care, as an estimated 90% of deaths due to PPH are preventable with early diagnosis and …

Modeling Of Nk Cells In Pediatric Patients With Unusually Severe Or Recurrent Hsv Using High-Dimensional Flow Cytometry, Yunran Feng

McKelvey School of Engineering Theses & Dissertations

HSV infection is broadly spread all over the world with some patients having severe and/or recurrent HSV infections. Our lab studies human Natural Killer (NK) cells, which are important in innate immune responses to viral infections and tumors. A publication in 2013 by Ornstein et al from our lab studied HSV+ pediatric patients and found some associations between severe infection and defects in NK cytolytic function. PLCG2 haploinsufficient variants found in 2 HSV patients causing PLCγ2 hypophosphorylation, and loss of cytolytic function in NK cells is a novel finding recently published by Alinger et al from our lab in 2023. …

The Role Of Voluntary Descending Control In Enhancing Motor Function Via Transcutaneous Spinal Cord Stimulation, Yoon Kim

McKelvey School of Engineering Theses & Dissertations

Spinal cord injury (SCI) is a life-changing event that causes lasting motor impairments. Transcutaneous spinal cord stimulation (tSCS), a non-invasive form of neuromodulation in which electrodes are placed on the skin and used to stimulate the spinal circuits via an electrical current, has demonstrated positive effects on motor function recovery in individuals who have had SCIs. However, the precise mechanism of how tSCS interacts with voluntary descending drive remains poorly understood. This study aims to investigate the role of voluntary descending control in influencing reflex responses triggered by tSCS.

Electromyography (EMG) recordings were performed in ten unimpaired individuals while they …

Mathematical Modeling For Dental Decay Prevention In Children And Adolescents, Mahdiyeh Soltaninejad

Dissertations

The high prevalence of dental caries among children and adolescents, especially those from lower socio-economic backgrounds, is a significant nationwide health concern. Early prevention, such as dental sealants and fluoride varnish (FV), is essential, but access to this care remains limited and disparate. In this research, a national dataset is utilized to assess sealants' reach and effectiveness in preventing tooth decay, particularly focusing on 2nd molars that emerge during early adolescence, a current gap in the knowledge base. FV is recommended to be delivered during medical well-child visits to children who are not seeing a dentist. Challenges and facilitators in …

Low Impedance, Durable, Self-Adhesive Hydrogel Epidermal Electrodes For Electrophysiology Recording, Naiyan Wu

McKelvey School of Engineering Theses & Dissertations

Traditional electrodes used for electrophysiology recording, characterized by their hard, dry, and inanimate nature, are fundamentally mismatched with the soft, moist, and bioactive characteristics of biological tissues, leading to suboptimal skin-electrode interfaces. Hydrogel materials, mirroring the high water content and biocompatibility of biological tissues, emerge as promising candidates for epidermal electronic materials due to their adjustable physicochemical properties. However, challenges such as inadequate electrical conductivity, elevated skin impedance, unreliable adhesion in moist conditions, and performance decline from dehydration have significantly restricted the efficacy and applicability of hydrogel-based electrodes. In this thesis, we report a high-performance hydrogel epidermal electrode patch for …

Tunable Dual-Phase Dual-Drug Delivery System Using A Plga Microparticle/Pva Hydrogel Composite, Timothy John Eck

Theses and Dissertations

Current drug-eluting coatings have demonstrated controlled long-term, sustained release but have only tried to mitigate short-term burst release as a negative side effect. For applications like wound healing, there is a need for a drug-eluting coating which is adjustable in both short- and long-term release, independent of each other. We present a tunable dual-phase dual-drug delivery coating composed of drug-loaded polymer microparticles and drug-loaded hydrogel which can control short term and long term release individually in this study. This coating was created using lidocaine and dexamethasone encapsulated in poly(D,L-lactide-co-glycolide) particles combined with lidocaine- and dexamethasone-loaded poly(vinyl alcohol) hydrogel. Hydrogel drug …

Physical And Geometrical Modulation Of Human Fibroblast Behaviour, Sarah M. Brooks

Electronic Thesis and Dissertation Repository

This thesis investigates the impact of mechanical stimuli, specifically substratum topography and elastic modulus, on dermal and gingival fibroblast behaviour associated with scarring and regeneration. Scar formation presents a significant issue for implanted biomaterials often leading to device failure. Even though scar formation is a normal end point to adult human dermal wound healing, gingival wounds are capable of tissue regeneration or scarless wound healing. Understanding how these cells respond to environmental cues, including substratum topography and elastic modulus, is central to the development of novel biomaterials for stimulation of tissue regeneration. It was hypothesized that topographic features, with submicron …

Bioactive And Electrically Conductive Nanocomposite Bone Biomaterials, Rebeca A. Arambula-Maldonado

Electronic Thesis and Dissertation Repository

Electrically conductive carbon-based materials are emerging as potential biomaterials for bone tissue engineering. Their incorporation into organic-inorganic nanocomposites mimics the structural composition and electrically conductive nature of bone.

The aim of this research was to design bone biomaterials from gelatin-based polymers, tertiary bioactive glasses (BG) via a sol-gel method, and multiwall carbon nanotubes (MWCNT). The incorporation of calcium into organic-inorganic nanocomposites plays an essential role in the development of bioactive bone biomaterials. Calcium chloride and calcium ethoxide were investigated as calcium sources in gelatin-BG-MWCNT nanocomposites. The resulting surface elemental distribution was homogeneous, but the swelling, degradation and porosity properties of …

Redesign Of Robotic Walking Training Device To Involve Zero Gravity Capabilities And Daily Activities, Chad Ballard

Mechanical Engineering Theses

Many patients struggle with disabilities that hinder their ability to walk. This project aimed to create a leg assembly capable of variable gravity so that it could be combined with a Robotic Walking Training Device, and lead to better rehabilitation options for patients. This was accomplished by deriving equations of joint torque, creating circuit diagrams for Arduino systems, modeling leg assemblies in CAD, and finally combining it to create a working small-scale prototype. The result of the prototype testing showed accurate movement on each joint, especially the ankle and knee segments, to create virtual zero gravity. In addition to this, …

Blow-Spun Hybrid Pcl-Peo/Hnts Scaffolds With Enhanced Biological And Mechanical Properties, Meichen Liu

Doctoral Dissertations

With the development of technology and engineering, nanotechnology has been a multidisciplinary scientific field applied in nearly all science areas, including medicine, genetics, food industry, robotics. In this respect, nanomedicine has gained increasing attention and been a useful, effective therapy for cancer diagnosis, gene transfer, and drug delivery. To design an ideal nano drug delivery system with controlled drug releasing and improved encapsulated drug’s pharmacokinetic and pharmacodynamic profiles, hydrogels and polymer composites have witnessed increased research interest during the last decades. Recently, numerous polymers have been studied to fabricate the ideal wound dressing with biocompatibility, biodegradability, porous structural, and suitable …

Development And Characterization Of Injectable, Cell-Encapsulated Chitosan-Genipin Hydrogels, Tyler R. Priddy-Arrington

Doctoral Dissertations

Over 150,000 patients undergo lower extremity amputation every year in the United States, most commonly caused by complications due to diabetes mellitus, peripheral vascular disease, and trauma. Diseased or damaged tissues that are unable to naturally repair themselves must either be fully removed or replaced, otherwise the injuries can lead to further complications such as infection or death. Tissue resection and amputation, as forms of removing damaged tissue, are not favorable to patients as they can cause pain, reduce mobility, and negatively impact quality of life. However, replacing lost or damaged tissues with donor tissues carries the risks of tissue …

Selective Targeting Of Microglia By Quantum Dots And Green Synthesis Of Metal Organic Biohybrids; Applications In Dynamic Cell And Assay Systems, Navya Uppu

Doctoral Dissertations

Neurological disorders are the leading cause of physical and cognitive disability across the globe, currently affecting approximately 15% of the worldwide population. Part of the glioma microenvironment are microglia, resident immune cells of the CNS that were thought to be involved in the pathogenesis of diverse neurodegenerative diseases. Though it remains uncertain what triggers microglial activation in these disorders, targeting and tracking microglial functions using nanotools like Quantum Dots (QDs) could help us elucidate them in such neurological diseases. This research focuses on the comparative study of different QDs formulations and their selective uptake by brain microglia in primary cultures …

Development Of An In Vitro 3-Dimensional Co-Culture Human Colorectal Cancer Model In Microfluidic Devices, Abby Jens

Master's Theses

Colorectal cancer is the second most common cause of cancer-related deaths in the United States, with the relative 5-year survival rate for distant stage cancer being only 14%. The most common treatment for colorectal cancer is with chemotherapeutic drugs; however, the discovery of these drugs is costly, time-consuming, and often requires the use of animal models that do not yield results that translate to clinical trials. Due to these shortcomings, researchers seek to develop physiologically relevant in vitro tumor models that more accurately mimic the tumor microenvironment for cheaper and faster high-throughput drug screening. The aim of this research was …

Comparison Of Scanning Electron Microscopy And Confocal Laser Microscopy For Tissue Surface Roughness Characterization, Tarnvir Dhaliwal

Master's Theses

It was found that the measurements captured by confocal microscopy and scanning electron microscopy had a statistically significant difference for bovine tissue. There was not a statistically significant for porcine and poultry tissue.

The intent of the study is to perform a comparative study to examine efficacy of two distinct technologies for a singular purpose: tissue surface roughness characterization. The two technologies compared are a confocal reflectance microscope and a scanning electron microscope. The comparison was made by comparing two surface roughness parameters [Ra and Rq] within ImageJ.

The study examined three different animal species [porcine, bovine, and poultry] to …

Tourniquet Pressure Gradient Measurement Apparatus, Luis Enrique Perez, Elsa Elizabeth Bates

Biomedical Engineering

The goal of this project was to design a device that would measure pressure gradient data across the width of an elastic and inelastic tourniquet cuff using a human limb model. The main customer requirements that were focused on were to accurately measure the pressure from a tourniquet, keep the cost down, and be easy to use. The targeted design specifications were to read pressure values ranging from 0-400 mmHg, keep the test length under 5 minutes, and to keep the cost of materials under $400. The design of the device ended up consisting of 5 IV pouches that were …

Auto Adjustable Flow Regulator, Ethan Hemmerlin, Jack Dooley

Biomedical Engineering

The Auto-Adjustable Oxygen Flowmeter device is to be used in conjunction with an oxygen source or reservoir, as well as a low-flow nasal cannula apparatus. The device is applicable for patients requiring an oxygen flow rate of 0-6 L/min. Further, the device works to maintain a healthy blood-oxygen concentration of 90-94% for typical patients, as well as an 88-92% range for COPD patients who are chronic CO2 retainers. A reflective pulse oximeter will record the SpO2 concentration of the patient. The outputted SpO2 concentration will be transmitted to an internal processing PCB from which it will interact with the oxygen …