Biomedical Engineering and Bioengineering Commons^™

The Effect Of Focused Ultrasound On Altering The Diameter Class Of Nerve Fibers Contributing To A Compound Evoked Potential, Analyzed Using A Perturbative Decomposition Technique., Megan Wurden

Master's Theses

Peripheral neuropathies are disorders that involve the damage of peripheral nerve fibers, affecting the ability of different parts of the body to communicate. A differentiating factor in diagnosis between various clinical conditions can be which size class of nerve fibers are affected. A nerve conduction velocity test can be used to assess the viability of the nerve but is a single-parameter test and gives no information about the population characteristics of the remaining active fibers. A method developed and previously reported by Szlavik (2016) utilizes a mathematical perturbed decomposition to determine the normalized frequency of each size class of fiber …

Studying The Efficacy Of An Injectable 3-Dimensional Fibrin Extracellular Matrix To Characterize The Effects Of Antitumor Agents On Sw620 Cells In A Microfluidic Device, Thèo Anastos

Master's Theses

Colorectal cancer is the third most common cancer in the United States and there is currently a lot of research going into new antitumor agents to kill the cancer. One method for replicating the tumor response to a drug in vivo is by creating an in vitro drug testing model to replicate the in vivo condition. This research project was conducted to determine the efficacy of testing tumor cultures in a microfluidic device as a way to provide accurate drug responses in vitro instead of using in vivo subjects in clinical trials. A total of four experiments were conducted with …

Computational Bone Mechanics Modeling With Frequency Dependent Rheological Properties And Crosslinking, Timothy G. Moreno

Master's Theses

Bone is a largely bipartite viscoelastic composite. Its mechanical behavior is determined by strain rate and the relative proportions of its principal constituent elements, hydroxyapatite and collagen, but is also largely dictated by their geometry and topology. Collagen fibrils include many segments of tropocollagen in staggered, parallel sequences. The physical staggering of this tropocollagen allows for gaps known as hole-zones, which serve as nucleation points for apatite mineral. The distance between adjacent repeat units of tropocollagen is known as D-Spacing and can be measured by Atomic Force Microscopy (AFM). This D-Spacing can vary in length slightly within a bundle, but …

Development Of A Robust Methodology To Obtain And Assess Myogenic Precursor Cells For Their Use In Regenerative Therapies, Ricardo Lasa

Master's Theses

Peripheral arterial occlusive disease (PAOD) is characterized by buildup of atherosclerotic plaque in peripheral arteries that leads to an occlusion that can interrupt the supply of blood to the peripheral tissue, causing downstream tissue ischemia/hypoxia. PAOD is estimated to affect over 200 million patients worldwide. Current surgical revascularization treatments can be effective in about half of the patient population, leading to a significant number of patients with no treatment options beyond pharmacological intervention and lifestyle modification. The decrease in blood flow downstream of the occlusion leads to increased blood pressure gradient in the microvasculature, specifically in vessels that connect arterial …

A Novel Method To Commercialize Medical Devices Initially Developed At California Polytechnic State University San Luis Obispo, Christina Grigorian

Master's Theses

California Polytechnic State University, San Luis Obispo is a university that encourages students to approach learning hands-on. As such, there is cutting-edge technology being developed by students in all departments on campus. Being that the university possesses an outstanding biomedical engineering department, there are groundbreaking medical devices that students are creating at Cal Poly SLO. These are devices that can better the lives of individuals suffering from ailments or fulfill needs in the medical industry. Subsequently, it is vital that these devices make it out of campus laboratories and into the hands of consumers. In order to move a product …

Analysis Of Electroanatomic Mapping System Accuracy Using X-Ray Reconstruction Of Electrode Locations In A Porcine Animal Model, Hana Boudlali

Master's Theses

Fluoroscopy is considered the gold standard for locating catheters during cardiac electrophysiology (EP) procedures. However, fluoroscopy emits ionizing radiation which can lead to adverse health effects when exposed to in high doses (World Health Organization, 2016). Electroanatomic mapping (EAM) systems display the three-dimensional location of EP catheters and measure the local electrical activity of the heart. They can minimize a physician’s reliance on fluoroscopy and can help reduce radiation exposure during a case (Casella, 2011).

EAM systems are diagnostic medical devices that inform the placement of ablation therapy and must accurately locate catheters to be deemed safe. Test methods to …

A Protocol For Achieving Adherent Cell Culture Within A Microfluidic Device, Tarra Danielle Sanders

Master's Theses

The goal of this study is to design a protocol for the adherent cell culture within a novel microfluidic device. Microscale cell culture protocols were developed for loading cells using poly-L-lysine to enhance adherent cell culture of murine derived NIH 3T3 fibroblasts. This work sought to develop a method for adherent microculture by examining various sterilization, surface treatment, and seeding techniques. Using a vacuum suction loading technique, air plasma treatment and a poly-L-lysine surface treatment adherent cell culture was observed within the device. The work presented here is part of a collaborative effort that aims to develop protocols for the …

Understanding The Effects Of Long-Duration Spaceflight On Fracture Risk In The Human Femur Using Finite Element Analysis, Keyanna Brielle Henderson

Master's Theses

Long-duration spaceflight has been shown to have significant, lasting effects on the bone strength of astronauts and to contribute to age-related complications later in life. The microgravity environment of space causes a decrease in daily mechanical loading, which signals a state of disuse to bone cells. This affects the bone remodeling process, which is responsible for maintaining bone mass, causing an increase in damage and a decrease in density. This leads to bone fragility and decreases overall strength, posing a risk for fracture. However, there is little information pertaining to the timeline of bone loss and subsequent fracture risk.

This …

Finite Element Analysis Of Total Knee Arthroplasty, Sean Yueh

Master's Theses

The total knee arthroplasty (TKA) has become one of the most successful procedures in all of medicine, with an average of over 966,000 operations performed a year. Since its introduction in 1968, the TKA’s surgical process and implant designs have continuously been improved to increase survivability. However, the need for a revision TKA – due to aseptic loosening – continues to be a problematic aspect of the procedure. Stress shielding induced by different design parameters of the implant has generated controversy in the determination of an ideal configuration. The purpose of this study is to investigate how implant design parameters …

Effects Of Marathon Training On Male And Female Femoral Stress Fracture Risk, Clara Lin

Master's Theses

Marathon runners are prone to femoral stress fractures due to the high magnitudes and frequencies of lower extremity loads during training. Female runners tend to have a greater incidence of stress fracture compared to male runners. Sex-specific differences in body structure, joint pressure, and muscle activation patterns that influence bone remodeling may cause this observed difference in stress fracture occurrence. The goal of this thesis was to develop a finite element model of the femur during marathon training, then determine if marathon training affected bone properties of male and female runners differently. To achieve this goal, a finite element femur …

Optimal Parameter Values For Accurate And Repeatable Nanoindentation Of Human Trabecular Bone, Stephen Matthew Kmak

Master's Theses

Nanoindentation techniques have not been standardized for use on bone tissues, making comparison of bone material properties obtained via nanoindentation across studies difficult and unreliable. This study determined a set of optimal parameter values for thermal drift correction time, dwell time, and loading rate that can be used to obtain accurate and repeatable material properties from human femoral trabecular bone through experimentation and statistical analysis. All testing was conducted using a single nanoindenter on a single trabeculae, with the assumption that material properties within the individual trabeculae were internally consistent. Parameters not of interest during this study, such as ambient …

Development And Optimization Of Imaging And Image Quantification Techniques For Tissue-Engineered Blood Vessel Mimics, Ashley Turcott

Master's Theses

Blood vessels mimics (BVMs) are tissue-engineered blood vessels used to test vascular devices in an environment that mimics some simple anatomical factors of native blood vessels. It is important to accurately and consistently assess tissue-engineered blood vessels, although there is currently a lack of standardization in Cal Poly’s Tissue Engineering Lab and in the entirety of the field. The goal of this thesis was to develop and optimize imaging and image quantification techniques for tissue-engineered blood vessels.

The first aim of this thesis optimized and compared imaging and assessment techniques for electrospun scaffolds. Images from different SEMs were compared to …

Smartphone-Tape Method For Calculating Body Segment Inertial Parameters For Analysis Of Pitching Arm Kinetics, Jay Sterner

Master's Theses

The objectives of this study were to (1) develop a non-invasive method (referred to as Smart Photo-Tape) to calculate participant-specific upper arm, forearm, and hand segment inertial properties (SIPs) (e.g. mass, center of mass, and radii of gyration) and (2) use those Smart Photo-Tape properties in inverse dynamics (ID) analyses to calculate injury-related pitching arm kinetics. Five 20- to 23- year-old baseball pitchers were photographed holding a baseball and analyzed using the Smart Photo-Tape method to obtain 3-D inertial properties for their upper arm, forearm, and hand. The upper arm and forearm segments were modelled as stacked elliptic cylinders and …

Investigation Of Experimental Variation Of Bovine Sphingomyelin As A Novel Ingredient For Ultraviolet Protection, Esther Chen

Master's Theses

Skin cancer is a prevalent disease that globally affects 2-3 million people per year [1]. This number is expected to grow tenfold as depletion of the ozone layer contributes to harsher rays reaching Earth’s surface [2]. A common way to protect against those ultraviolet waves is to apply sunscreen, however, recent reports call into question the safety of some active ingredients as they can enter through the skin into the bloodstream [3]. This thesis aims to investigate an alternative solution that uses bovine sphingomyelin (BSM) as photoprotective solution against UV irradiation.

In order to evaluate the effectiveness of BSM against …

Design Of Prototype Prosthesis For A Canine With A Right Front Limb Deformity As An Alternate Approach To Stabilize Gait And Withstand Gait Forces, Tayler R. Kastlunger

Master's Theses

Congenital and developmental limb deformities in canines are rare and can occur as a genetic disorder or be caused by extrinsic factors. Without surgery to correct the deformity, conservative management can be implemented to manage exercise and restrict high-intensity activity of the canine. However, any alteration to the normal gait and locomotive biomechanics of a canine can have significant long-term effects on the musculoskeletal health and quality of life of the canine. To improve quality of life and provide an alternative and more cost-effective approach to surgery, a custom prosthetic was designed and developed for a canine born with a …

Subject-Specific Finite Element Models Of The Human Knee For Transtibial Amputees To Analyze Tibial Cartilage Pressure For Gait, Cycling, And Elliptical Training, Jonathon Stearns

Master's Theses

It is estimated that approximately 10-12% of the adult population suffers from osteoarthritis (OA), with long reaching burdens personally and socioeconomically. OA also causes mild discomfort to severe pain in those suffering from the disease. The incidence rate of OA for individuals with transtibial amputations is much than average in the tibiofemoral joint (TF). It is well understood that abnormal articular cartilage stress, whether that be magnitude or location, increases the risk of developing OA. Finite element (FE) simulations can predict stress in the TF joint, many studies throughout the years have validated the technology used for this purpose. This …

Skier's Edge: Biomechanical Analysis, Benjamin T. Johannes

Master's Theses

ABSTRACT

Skier’s Edge: Biomechanical Analysis

Benjamin T. Johannes

The Skier’s Edge trainer can be used by novice or expert skiers. Testing was performed to analyze if the use of the Skier’s Edge could reduce in shear forces of the valgus moment on the knee joint and anterior cruciate ligament (ACL) due to lesser fatigue of muscle and a higher hamstring to quadricep (H/Q) ratio activity. This leads to a reduction of improper form and an increase in balance. Experiments performed observed the change in muscle activity with the use of the Skier’s Edge over time when compared to other forms …

Insulative (Direct Current) Dielectrophoretic Foul-Less Filtration In Microfuidic Systems, Matthew A A Whitman

Master's Theses

Filtration is a technology that is used almost ubiquitously in society from uses raging from filtration of macroparticles from water to pharmaceutical grade filtration products to remove anything larger than a protein. However, with such a wide range of uses, most filtration products have the same issue; membrane clogging (fouling) that prevents continuous use and requires frequent maintenance. This thesis hypothesizes that by applying a direct current (DC) to an insulating array of posts, they will create a foul-less insulative dielectrophoretic filter (iDEP) that does not clog since particles will levitate above the insulating array.

This thesis tested an inherited …

Methods To Increase Algae Biomass Productivity In Raceway Pond Monocultures, Ryan S. Anderson

Master's Theses

The economics of algae biofuels and bioproducts would be improved by increased biomass productivity. Two studies on this potential are described in this thesis – one on a locally isolated filamentous yellow-green alga and the other on a planktonic strain genetically improved via selective enrichment.

Polycultures have been viewed as productive, stable, and, in some cases, harvestable by natural bioflocculation. Local native strains might have higher productivity than culture collection strains because they are already adapted to local outdoor conditions. In this study, the filamentous yellow-green alga Tribonema minus was isolated from a local volunteer polyculture. Its productivity as a …

Electrochemical Detection Of Reactive Oxygen Species Via A Platinum Microelectrode Array, Victor M. Carriere Jr.

Master's Theses

Oxidative stress, an excess of endogenous or exogenous reactive oxygen species (ROS) in the body, is closely aligned with inflammatory responses. ROS such as hydrogen peroxide, superoxide, and radical hydroxyl ion serve essential functions in fighting infection, but chronic elevation of these species irreversibly damages cellular components. Given the central role of inflammation in a variety of diseases, including Alzheimer’s Disease, atherosclerosis, and rheumatoid arthritis, a low-cost, extracellular, non-invasive assay of ROS is needed.

This work reports the use of a platinum microelectrode array (Pt MEA)-based ceramic probe to detect time- and concentration-dependent variations in hydrogen peroxide (H2O2) production by …

Single-Cell Impedance Spectroscopy, David Paul Lange

Master's Theses

Impedance spectroscopy (IS) is an important tool for cell detection and characterization in medical and food safety applications. In this thesis, the Cal Poly Biofluidics Lab’s impedance spectroscopy system was re-evaluated and optimized for single-cell impedance spectroscopy. To evaluate the IS system, an impedance spectroscopy bioMEMS chip was fabricated in the Cal Poly Microfabcrication lab, software was developed to run IS experiments, and studies were run to validate the system. To explore IS optimization, Maxwell’s mixture theorem and the Schwartz-Christoffel transform were used to calculate an analytic impedance solution to the co-planar electrode system,a novel volume fraction to account for …

Improving Paper-Based Microfluidic Mixing With The Incorporation Of Flow Disrupting Structures, Hannah C. Green

Master's Theses

Paper-based microfluidic devices provide a light-weight, cost effective platform for diagnostic and analytical testing. The goal of this project is to enhance paper-based microfluidic mixing by incorporating fluid flow disrupting structures (referred to here as rib bones) into the microdevice design to expand the analytical capabilities of paperbased microfluidic devices. The devices are fabricated on Whatman CHR-1 chromatography paper. The devices are designed in SolidWorks and printed using a solid ink printer (ColorQube 8580). The wax is penetrated into the paper to create hydrophobic barrier regions by heating in a convection oven until the wax is fully penetrated. The parameters …

From Experimental Studies To Coarse-Grained Modeling: Characterization Of Surface Area To Volume Ratio Effects On The Swelling Of Poly (Ethylene Glycol) Dimethacrylate Hydrogels, Gabriel Zahm

Master's Theses

Understanding the performance of widely applied nanoscale hydrogel biomaterials is an unmet need within the biomedical field. The objective of this master’s thesis project was to evaluate the effects size and surface area has on the in vivo behavior of nanoscale hydrogels. The hypothesis tested was that at the nanoscale, the increased surface area to volume effects of nanoscale hydrogels play and important role in the overall swelling of hydrogels, such that nanoscale hydrogels swell to a greater degree than their bulk counterparts. To investigate this, the bulk swelling behavior of a series of neutral poly (ethylene glycol) di-methacrylate (PEGDMA) …

Metal Related Nanoparticles' Physical Behaviors In Different Physiologica Environments, Muhetaer Tuerhong

Master's Theses

In the past decades, the development of nanotechnology has had tremendous successes in material science. In this technology, the pertinent materials are used at the intermediate scale between individual molecules and their size in the nanometer region(1-100nm) compared to bulk materials. This nanoscale size provides a larger surface area; therefore, nanoparticles would be perfect essential components of nanotechnology. The reduced size of nanoparticles has a larger surface ratio to volume, which can modify their chemical, mechanical, structural, and electrical properties.

In this study, the main goal is to test different metal related nanoparticles, such as CuNPs (Copper nanoparticles), FeNPs (Iron …

Customization Of Aneurysm Scaffold Geometries For In Vitro Tissue-Engineered Blood Vessel Mimics To Use As Models For Neurovascular Device Testing, Camille D. Villadolid

Master's Theses

Cerebral aneurysms occur due to the ballooning of blood vessels in the brain. Rupture of aneurysms can cause a subarachnoid hemorrhage, which, if not fatal, can cause permanent neurologic deficits. Minimally invasive neurovascular devices, such as embolization coils and flow diverters, are methods of treatment utilized to prevent aneurysm rupture. The rapidly growing market for neurovascular devices necessitates the development of accurate aneurysm models for preclinical testing. In vivo models, such as the rabbit elastase model, are commonly chosen for preclinical device testing; however, these studies are expensive, and aneurysm geometries are difficult to control and often do not replicate …

Transmission Probability Of Embolic Debris Through The Aortic Arch And Daughter Vessels During A Transcatheter Aortic Valve Replacement Procedure, Jessica Lena Wirth

Master's Theses

Cerebral ischemia leading to an ischemic stroke is a possible complication of a transcatheter aortic valve replacement (TAVR) procedure. This is because embolic debris can become dislodged and travel through the aortic arch, where they either continue to the descending aorta and join the systemic circulation or travel into the cerebral vasculature through the three daughter vessels that branch off the top of the aortic arch. These three vessels are the brachiocephalic artery, the left subclavian artery, and the left common carotid artery. These three vessels lead either directly or indirectly to the cerebral vasculature, where the diameter of vessels …

Study Of Paper Microbial Fuel Cells For Use In On-Site Wastewater Testing, William A. Tolmasoff

Master's Theses

This study demonstrated a technique for fabricating simple, low-cost Paper Microbial fuel cells (PMFC’s) in the model of a previous study to, for the first time, produce voltage from wastewater effluent. The PMFC’s were created by stacking and gluing the main components of an MFC together: reservoir layer; anode; cation exchange membrane (CEM); air cathode. A wax printer was used to create the hydrophobic borders of the PMFC’s on filter paper, and graphite paint was applied to the paper to create the anode. The CEM’s considered were filter paper, wax, and Nafion, with Nafion being the most efficient. Finally, the …

A 3-Dimensional In Silico Test Bed For Radiofrequency Ablation Catheter Design Evaluation And Optimization, Carolyn Teng

Master's Theses

Atrial fibrillation (AF) is the disordered activation of the atrial myocardium, which is a major cause of stroke. Currently, the most effective, minimally traumatic treatment for AF is percutaneous catheter ablation to isolate arrhythmogenic areas from the rest of the atrium. The standard in vitro evaluation of ablation catheters through lesion studies is a resource intensive effort due to tissue variability and visual measurement methods, necessitating large sample sizes and multiple prototype builds. A computational test bed for ablation catheter evaluation was built in SolidWorks® using the morphology and dimensions of the left atrium adjacent structures. From this geometry, the …

Evaluation Of Human Umbilical Vein Endothelial Cells In Blood Vessel Mimics Through Changes In Gene Expression And Caspase Activity, Conor Charles Hedigan

Master's Theses

Blood vessel mimics (BVMs) are simple tissue engineered blood vessel constructs intended for preclinical testing of vascular devices. This thesis developed and implemented methods to characterize two of these components. The first aim of this thesis investigated the effect of cell culture duration and flow conditions on endothelial cell gene expression, especially regarding endothelial-to-mesenchymal transition (EndMT). A trend of decreased endothelial marker gene expression and increased mesenchymal marker gene expression would indicate EndMT. qPCR analysis revealed that increased cell culture duration did not result in EndMT, and in fact increased endothelial marker expression as cell culture duration increased. Disturbed flow …

Interpolated Perturbation-Based Decomposition As A Method For Eeg Source Localization, Gabriel Zelik Lipof

Master's Theses

In this thesis, the perturbation-based decomposition technique developed by Szlavik [1] was used in an attempt to solve the inverse problem in EEG source localization. A set of dipole locations were forward modeled using a 4-layer sphere model of the head at uniformly distributed lead locations to form the vector basis necessary for the method. Both a two-dimensional and a pseudo-three-dimensional versions of the model were assessed with the two-dimensional model yielding decompositions with minimal error and the pseudo-three-dimensional version having unacceptable levels of error. The utility of interpolation as a method to reduce the number of data points to …