Biomedical Engineering and Bioengineering Commons^™

Measuring Gait Of Total Knee Arthroplasty Patients Pre-Op And Post-Op Using A Smartphone, Celeste A. Thai

Master's Theses

Motion capture technology is a tool often used in orthopedic applications, including measuring gait dysfunctions. However, gait analysis research focused on total knee arthroplasty (TKA) patients is limited, especially using motion capture systems. This may be due to a multitude of factors, such as inaccessibility to gait labs to the general public, difficulty of travel post-surgery, and overall costs of care and maintenance of motion lab equipment. New emerging novel methods use wearable devices such as smartphones and inertial measurement devices (IMUs) to perform gait assessment and are becoming favorable due to their increasingly ubiquitous nature. One such method using …

Design And Testing Of A Prototype Prosthesis For Pediatric Upper-Limb Transradial Amputees To Provide Adjustable Size And Modular Characteristics, Paul Heli

Master's Theses

This study was conducted to develop a financially accessible body-powered upper-limb prosthetic socket that can be adjusted to maintain fit and function for a growing child with a transradial amputation. The main objectives of the study were to design, manufacture, and test a device that was comfortable, functional, affordable, and adjustable. The socket was designed to be comfortable using global variables controlling the computer-aided design (CAD) model size with user-specific measurements. Comfort was also incorporated using shape-forming of the socket for specific residual limb features. The device was designed to perform the two main functions of suspension, or attachment to …

Development Of A Pressure Sensing System Coupled With Deployable Machine Learning Models For Assessing Residual Limb Fit In Lower Limb Prosthetics, Maxwell D. Lewter

Master's Theses

Lower limb amputations pose significant challenges for patients, with over 150,000 cases annually in the U.S., leading to a high demand for effective prosthetics. However, only 43% of lower limb prosthetic users report satisfaction, primarily due to issues with socket fit, which is critical for comfort, stability, and preventing injury. This study presents a deployable sensing system for potentially real-time monitoring of prosthetic socket fit by using pressure sensors and convolutional neural networks (CNNs) to analyze the pressure distribution within the socket. A novel CNN architecture, utilizing both dilated and strided convolutions, is proposed to effectively capture spatial-temporal patterns in …

Hypoxic Incubator: Improving Robustness/Reliability And Demonstrating Physiological Efficacy, Damon Dennis Tan

Master's Theses

The Microphysiological Systems Laboratory aims to develop colorectal cancer tumor models under a hypoxic environment to assess model response to pharmaceutical compounds in vitro. To perform relevant studies, researchers have attempted to use different hypoxic inducing strategies such as a nitrogen pod and hypoxic incubator to recreate in vivo physiological responses to hypoxia. However, studies would be interrupted due to incubator functionality failure. To ensure successful and physiologically relevant studies, I improved and verified the robustness and reliability of a hypoxic incubator previously designed and manufactured in the lab. Through the testing and iterating design processes, I engineered and implemented …

3d Printed Microfluidic Fabrication Methodology, Characterization, Mechanical Design, And Applications In Electrostatic Artificial Muscles And Benthic Microbial Fuel Cells, Terak B. Hornik

Master's Theses

The fabrication of microfluidic devices often requires specialized methods. The development of these methods requires careful characterization and understanding of the processes involved. Using primarily PolyJet 3D printing technology, microfluidics offers a wide scope of applications such as microfluidic benthic microbial fuel cells (MBMFCs) and electrostatic artificial muscles. MBMFCs benefit from the confinement of the microbes resulting in close proximity between the electrode and the organisms. Using a modular design called the Sponge, assembly and upscaling is possible. Electrostatic artificial muscles benefit from a microfluidic approach due to the non-linearity of electrostatic attraction creating disproportionate benefits when miniaturized. When designed …

Dual Base Sige Is-Hbt For Use In Biosensing Applications, Liam Stephen Hayes

Master's Theses

The proposed research is for a novel SiGe-based Ion-Sensitive Dual Hetero-junction Bipolar Transistor (IS-HBT) to be used in both trans-dermal biological sensing as well as Lab-on-Chip (LOC) applications. The end goals for the device designed are two: For one, the research done for this work will be used to substantiate the claims made by Zafar et al. [1] that an HBT-style structure is better suited for biosensing application rather than a conventional Field Effect Transistor (FET) based geometries. Secondly, it provides the final element to be integrated along with a selectivity membrane, as well as with a reverse-iontophoresis system to …

Development Of An Advanced Step Counting Algorithm With Integrated Activity Detection For Free Living Environments, Paige M. Dolan

Master's Theses

Physical activity plays a crucial role in maintaining overall health and reducing the risk of various chronic diseases. Step counting has emerged as a popular method for assessing physical activity levels, given its simplicity and ease of use. However, accurately measuring step counts in free-living environments presents significant challenges, with most activity trackers exhibiting a percent error above 20%. This study aims to address these challenges by creating a machine learning algorithm that leverages activity labels to improve step count accuracy in real-world conditions. Two approaches to balancing data were used: one employed a simpler oversampling technique, while the other …

Engineering An Injectable Hydrogel With Self-Assembling 3d Vasculature, Kendyl Cohn

Master's Theses

This research developed methods for culturing self-assembling capillaries in an injectable gel as a potential method for vascularizing tissue-on-a-chip models to mimic physiological drug delivery. Additionally, a mathematical model was developed as a tool for understanding nutrient delivery and comparison of potential delivery systems. Organs-on-a-chip provide novel platforms for studying biology and physiology in 3D, allow exploration of tissue engineering on a manageable scale, and serve as models for drug screening and drug-delivery testing.

Methods were first developed for co-culture of endothelial cells and fibroblasts (3T3s or HDFs) in 2D, evaluating culture time, seeding density and ratio of HUVECs and …

Thermal Preconditioning Effects On Perforation Propensity Of Transvenous Implantable Cardiac Leads Used For Pacing And Defibrillation, Diane Muff

Master's Theses

Thermal preconditioning to simulate shipping, handling and storage conditions did not affect distal tip stiffness values for permanently implantable cardiac leads used for pacing and defibrillation. Leads that were subjected to extreme temperatures and temperature cycling did not show changes in buckle force values compared with control specimens which were maintained at ambient room conditions. Absolute differences between all measurements were small, generally under 0.05 N and were attributable to measurement variability.

Buckle force values are used to assess the propensity of leads to perforate the heart, a rare but potentially serious complication of implantable pacing and defibrillation systems. Since …

Accessible Real-Time Eye-Gaze Tracking For Neurocognitive Health Assessments, A Multimodal Web-Based Approach, Daniel C. Tisdale

Master's Theses

We introduce a novel integration of real-time, predictive eye-gaze tracking models into a multimodal dialogue system tailored for remote health assessments. This system is designed to be highly accessible requiring only a conventional webcam for video input along with minimal cursor interaction and utilizes engaging gaze-based tasks that can be performed directly in a web browser. We have crafted dynamic subsystems that capture high-quality data efficiently and maintain quality through instances of user attrition and incomplete calls. Additionally, these subsystems are designed with the foresight to allow for future re-analysis using improved predictive models, as well as enable the creation …

Comparing Proliferation Rates And Collagen Production Of Cells Treated With Cuhars, Katie Elizabeth Mckenzie

Master's Theses

Cartilage is the padding in joints that protects the bones and aids in motion. Problems with the cartilage in the knee can be caused by mechanical damage or diseases like osteoarthritis. Chondrocytes make cartilage. The objective of this study is to determine the doubling time of chondrocytes per passage. I also want to determine the base amount of collagen-II created by chondrocytes as they age. I also want to determine how long it takes CuHARS to break down in different cell medias. Chondrocytes, human dermal fibroblasts, and CRL 2303 cells were grown and cultured for over a year. During that …

Manufacturing Silicone In-House For The Creation Of Customized Neurovascular Blood Vessel Mimics, Jacob Wilbert Perisho

Master's Theses

The Tissue Engineering Lab at California Polytechnic State University San Luis Obispo focuses on creating tissue-engineered Blood Vessel Mimics (BVMs) designed for the preclinical testing of neurovascular devices. These BVMs are composed of silicone models, representing anatomically accurate neurovasculatures, that are sodded with vascular cell types and then cultivated in bioreactors (which maintain physiologic conditions). These silicone models are currently sourced externally from industry partners, so the primary goal of this thesis was to develop the means and methods for the Tissue Engineering Lab to manufacture silicone models in-house.

The first aim of this thesis was to develop and explore …

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 …

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 …

Development Of A Cell Culture Incubator Capable Of Providing A Hypoxic Environment, Grant Austin Coe

Master's Theses

In order to perform more robust and physiologically relevant research, the Microphysiological Systems laboratory required a method of culturing cells where the level of oxygen could be adjusted. To fulfill this need, I designed and manufactured a hypoxic cell culture incubator. I employed a Quality Function Deployment to understand the customer requirements and convert them into engineering specifications. Based on these specifications, I created various conceptual designs. I evaluated the conceptual designs as compared to existing products and decided to move forward with the control system separated from a small, standard chamber. I developed the circuitry schematics for the temperature …

Finite Element Analysis Of The Bearing Component Of Total Ankle Replacement Implants During The Stance Phase Of Gait, Timothy S. Jain

Master's Theses

Total ankle replacement (TAR) implants are an effective option to restore the range of motion of the ankle joint for arthritic patients. An effective tool for analyzing these implants’ mechanical performance and longevity in-silico is finite element analysis (FEA). ABAQUS FEA was used to statically analyze the von Mises stress and contact pressure on the articulating surface of the bearing component in two newly installed fixed-bearing total ankle replacement implants (the Wright Medical INBONE II and the Exactech Vantage). This bearing component rotates on the talar component to induce primary ankle joint motion of plantarflexion and dorsiflexion. The stress response …

Evaluation Of Polyvinyl Alcohol (Pva) For Electrospinning Utility In The Blood Vessel Mimic (Bvm) Lab, Logan Vandenbroucke

Master's Theses

Electrospinning has provided the opportunity to create extracellular matrix (ECM) mimicking scaffolds for the development of tissue-engineered constructs. Within Professor Kristen Cardinal’s Blood Vessel Mimic (BVM) Lab, at Cal Poly, there exists a constant demand for innovation and the expansion of polymer types and electrospinning capabilities for its BVM model. Along these lines, the BVM Lab has recently acquired two new electrospinning systems: the Spinbox, a commercially graded electrospinning system, and the Learn-By-Doing system, which was part of a recently completed thesis conducted by Jason Provol. Additionally, recently published literature has demonstrated polyvinyl alcohol (PVA) as a viable option for …

Effects Of Beet Supplements On Cardiovascular Response Using A Noninvasive Blood Pressure Cuff, Nicholas M. Hughes

Master's Theses

A Calibrated Cuff Plethysmography device was built, tested for verification, and used to experiment on human subjects to measure the cardiovascular response of consuming a beet supplement, specifically looking at arterial compliance and pressure-area curves. Each subject was tested four times. A baseline was measured under normal conditions and after five-minute hyperemia conditions. 10 subjects were given 6 ounces of water mixed with either purple Kool-Aid (control), a SuperBeets supplement, or a SuperBeets Sport supplement and after 45 minutes, measurements were taken undergoing normal and hyperemia conditions once more. The verification testing demonstrated the calibration of the device was effectively …

Novel Method Of The Quantification Of Turbulent Fluid Flow In Silicone Artery Phantoms Using Acoustic Analysis, Julia Wong

Master's Theses

Cardiovascular disease is the leading cause of death globally and is responsible for taking 17.9 million lives per year. Despite the use of clinical treatments and detection methods, there remains a large population of individuals that suffer from CVD whose symptoms are left undetected and untreated prior to a life-threatening cardiac event. This highlights a need for an early detection method that can prevent the manifestation and worsening of the disease as well as address limitations of current early detection methods. An area of interest for early detection of CVD is subclinical atherosclerosis, which is the long, early, asymptomatic stage …

Development Of An Angiogenic Tissue-On-A-Chip Microenvironment, Eric Stuehr

Master's Theses

Preclinical testing is necessary to investigate the safety and efficacy of novel therapeutics before moving to clinical trials, yet approximately 90% of these therapies fail once tested in humans. This has led to increased interest in developing robust preclinical models that accurately mimic the complex human in vivo physiology. Microfluidic devices that can introduce dynamic conditions to 3D cell/organoid cultures, also known as tissue-on-a-chip, have emerged as physiologically relevant in vitro preclinical models that can achieve high throughput screening of therapeutics. The research presented here aimed to develop an angiogenic environment within a novel microfluidic device to stimulate formation of …

Using Noninvasive Calibrated Cuff Plethysmography To Observe The Effects Of Cold-Water Immersion On Arterial Compliance, Rita M. Grigorian

Master's Theses

As the prevalence of cardiovascular diseases continues to exponentially grow in populations across the globe, the necessity of determining underlying factors, effective methods of diagnoses, and universally available preventive measures also grows. Early detection of endothelial dysfunction, a proven precursor of cardiovascular diseases, can be extremely impactful in encouraging preventative measures and early intervention before medical conditions become chronic. In recent years, ice plunging, a form of cryotherapy involving full body immersion in cold water, has gained popularity within circles of fitness and health practitioners, gaining the interest of people of all backgrounds. Certain parallels observed between the human physiological …

Subject-Specific Human Knee Fea Models For Transtibial Amputees Vs Control Tibial Cartilage Pressure In Gait, Cycling And Elliptical Training, Ali Yazdkhasti

Master's Theses

Millions of individuals around the globe are impacted by osteoarthritis, which is the prevailing type of arthritis. This condition arises as a result of gradual deterioration of the protective cartilage that safeguards the ends of the bones. This is especially true of transtibial amputees, who have a significantly higher incidence of osteoarthritis of the knee in their intact limb than non-amputees. Engaging in regular physical activity, managing weight effectively, and undergoing specific treatments can potentially slow down the advancement of the disease and enhance pain relief and joint function. Nevertheless, the relationship between the type of exercise and its impact …

Characterization And Estimation Of Musculoskeletal Pain Using Machine Learning, Boluwatife Faremi

Master's Theses

Traditional scales utilized for recording pain are known to be highly subjective and biased due to inaccuracies in recollecting actual pain intensities. As a result, machine learning (ML) models that are trained using these scores as ground truth are reported to have low performance for objective pain classification because of the huge disparity between what was felt in moments of pain and the scores recorded afterward.

In the present study, two devices were designed for gathering real-time, continuous in-session subjective pain scores and the recording of the autonomic nervous system (ANS) altered endodermal (EDA) activity. 24 participants were recruited to …

Static Vascular Modeling Of Diabetes Progression, Andrea Skattenborg

Master's Theses

Cardiovascular disease is the leading cause of mortality in diabetic patients, and diabetes is one of the main causes of cardiovascular disease. Risk factors for cardiovascular disease result in structural and functional changes in the vascular wall. Arterial stiffness is a prominent structural change observed in the arterial wall that can be measured in clinical settings. The purpose of this thesis was to create a static model of the changes in arterial stiffness seen in diabetes. Elastic tubes with varying wall thicknesses were used to create artificial arteries for this purpose. Compliance (inverse of stiffness) of the arteries was determined …

Design And Validation Of A Wearable Smartsole For Continuous Detection Of Abnormal Gait, Karoline M. Wucherer

Master's Theses

Residual gait abnormalities are common following lower limb injury and/or stroke and can have several negative impacts on an individual’s life. Without continuous treatment and follow up, individuals can be prone to chronic pain as abnormal gait may lead to non-physiological loading of the musculoskeletal system. The current industry gold standard for diagnosing abnormal gait requires specialty equipment that is generally only available at designated gait facilities. Due to the inaccessibility and high cost associated with these facilities, a wearable SmartSole device to continuously detect abnormal gait was proposed. A previous iteration of the SmartSole was unable to properly detect …

Analytical Pipeline To Facilitate Electroencephalography Pain State Identification In Patients With Chronic Low Back Pain, Emma Katharina Jacobs

Master's Theses

Chronic low back pain (cLBP) affects the quality of life of over 23% of American adults and places an immense burden on the economy.^1–3 To more effectively diagnose and treat cLBP, quantitative biomarkers are needed to objectively measure pain and better identify the underlying mechanisms of cLBP. The overarching goal of this work is to create an analytical pipeline to investigate brain activity patterns measured with electroencephalogram (EEG) data of cLBP patients treated with transcutaneous spinal cord stimulation (tSCS). The specific aims of this project are to 1) investigate whether there is a difference between baseline EEG measurements and …

Analysis Of Arterial Compliance Using A Surrogate Arm Bench Top Model For The Validation Of Oscillometric Blood Pressure Methods, Christopher J. Cunningham

Master's Theses

A study was performed on a recently developed prototype of the Yong-Geddes surrogate arm design to collect compliance data of the various system components and determine the accuracy of measurements made through the bench top model. The study was performed to perceive the effectiveness of the model as a tool for validating non-invasive blood pressure detection monitors. Three stages of testing were performed to gather pressure and volume data from an artificial artery component, a sphygmomanometer, and the surrogate arm system to produce compliance estimations. Mathematical equations from supported arterial hemodynamics studies and clinical trials were applied to the pressure …

Implementation Of Methods For Cell Therapy Research And Assessment Of The Impact Of Cryopreservation, Samantha Lynes

Master's Theses

Cell therapy is the administration of living cells into a patient to prevent or treat a variety of diseases and illnesses. The cell therapy industry is rapidly expanding, and continued research is necessary for manufacturing safe and effective therapies. Although cell therapy manufacturing generally involves cryopreservation processes for storage, there are limited standards for cryopreservation processes and assays required to evaluate cell therapies post-thaw, and limited understanding exists about how a recovery period post-thaw could impact cell health. The overall goal of this thesis was to evaluate the effect of cryopreservation and potential subsequent recovery time on cell viability.

Because …

Rattus Norvegicus As A Biological Detector Of Clandestine Remains And The Use Of Ultrasonic Vocalizations As A Locating Mechanism, Gabrielle M. Johnston

Master's Theses

In investigations, locating missing persons and clandestine remains are imperative. One way that first responder and police agencies can search for the remains is by using cadaver dogs as biological detectors. Cadaver dogs are typically used due to their olfactory sensitivity and ability to detect low concentrations of volatile organic compounds produced by biological remains. Cadaver dogs are typically chosen for their stamina, agility, and olfactory sensitivity. However, what is not taken into account often is the size of the animal and the expense of maintaining and training the animal. Cadaver dogs are typically large breeds that cannot fit in …

Trace Dna Detection Using Diamond Dye: A Recovery Technique To Yield More Dna, Leah Davis

Master's Theses

This study aspires to find a new screening approach to trace DNA recovery techniques to yield a higher quantity of trace DNA from larger items of evidence. It takes the path of visualizing trace DNA on items of evidence with potential DNA so analysts can swab a more localized area rather than attempting to recover trace DNA through the general swabbing technique currently used for trace DNA recovery. The first and second parts consisted of observing trace DNA interaction with Diamond Dye on porous and non-porous surfaces.

The third part involved applying the Diamond Dye solution by spraying it onto …